Replace better-sqlite3 with built-in SQLite drivers

chore: release 0.2.0
docs: document space isolation usage
2026-05-12 16:52:22 +09:00 · 2026-05-11 19:13:52 +09:00 · 2026-05-11 14:45:35 +09:00 · 2026-05-11 14:45:28 +09:00 · 2026-05-11 14:28:08 +09:00
23 changed files with 1076 additions and 228 deletions
--- a/.gitea/workflows/npm-release.yml
+++ b/.gitea/workflows/npm-release.yml
@@ -18,7 +18,7 @@ jobs:
    name: verify
    runs-on: ubuntu-latest
    container:
-      image: node:20-bookworm
+      image: node:22-bookworm
    timeout-minutes: 20

    steps:
@@ -70,7 +70,7 @@ jobs:
    name: publish to npm
    runs-on: ubuntu-latest
    container:
-      image: node:20-bookworm
+      image: node:22-bookworm
    timeout-minutes: 20
    needs:
      - verify
--- a/README.md
+++ b/README.md
@@ -15,9 +15,9 @@ A single fact like `I have worked with TypeScript since 2025.` can connect the t
 ## Current capabilities

 - SQLite, PostgreSQL, MySQL, and MariaDB connection adapters
- Automatic schema initialization for `topics`, `facts`, `fact_topics`, `topic_relations`, `topic_aliases`, and `fact_embeddings`
+- Automatic schema initialization for `spaces`, `topics`, `facts`, `fact_topics`, `topic_relations`, `topic_aliases`, and `fact_embeddings`
 - High-level APIs for adding topics and facts
- Topic hierarchy APIs for parent/child traversal and lineage lookup
+- Hard space isolation so independent memory graphs can coexist without cross-linking
 - Topic alias and canonical resolution APIs so facts and queries can resolve alternate names
 - Semantic fact indexing and search APIs built around provider-agnostic embeddings
 - Dedup-aware ingestion hooks that can reuse an existing fact when a semantic near-duplicate is detected
@@ -25,6 +25,8 @@ A single fact like `I have worked with TypeScript since 2025.` can connect the t

 ## Install

+SQLite connections use built-in runtime drivers: `bun:sqlite` under Bun and `node:sqlite` under Node 22+. Run SQLite-backed IdentityDB workloads with Bun or Node 22+. PostgreSQL/MySQL/MariaDB adapters remain usable from Node without SQLite.
+
 ```bash
 bun install
 ```
@@ -101,6 +103,34 @@ console.log(matches.map((entry) => [entry.statement, entry.score]));
 await db.close();
 ```

+## Memory spaces
+
+IdentityDB now supports hard isolation via spaces. If you write facts into `spaceName: 'A'` and `spaceName: 'B'`, they behave like separate dimensions:
+
+- the same topic name can exist in both spaces
+- aliases resolve only inside the requested space
+- hierarchy, connected-topic traversal, semantic search, and duplicate detection stay inside the same space
+
+```ts
+await db.upsertSpace({ name: 'A' });
+await db.upsertSpace({ name: 'B' });
+
+await db.addFact({
+  spaceName: 'A',
+  statement: 'TypeScript belongs to A.',
+  topics: [{ name: 'TypeScript', category: 'entity', granularity: 'concrete' }],
+});
+
+await db.addFact({
+  spaceName: 'B',
+  statement: 'TypeScript belongs to B.',
+  topics: [{ name: 'TypeScript', category: 'entity', granularity: 'concrete' }],
+});
+
+const alphaFacts = await db.getTopicFacts('TypeScript', { spaceName: 'A' });
+const betaFacts = await db.getTopicFacts('TypeScript', { spaceName: 'B' });
+```
+
 ## Semantic ingestion and duplicate detection

 If you provide an embedding provider during ingestion, IdentityDB can index the new fact automatically and reuse an existing fact when a semantic near-duplicate is already present.
--- a/bun.lock
+++ b/bun.lock
@@ -5,13 +5,11 @@
    "": {
      "name": "identitydb",
      "dependencies": {
-        "better-sqlite3": "^12.1.1",
        "kysely": "^0.28.8",
        "mysql2": "^3.15.3",
        "pg": "^8.16.0",
      },
      "devDependencies": {
-        "@types/better-sqlite3": "^7.6.13",
        "@types/node": "^24.0.0",
        "@types/pg": "^8.20.0",
        "tsup": "^8.5.0",
@@ -131,8 +129,6 @@

    "@rollup/rollup-win32-x64-msvc": ["@rollup/rollup-win32-x64-msvc@4.60.3", "", { "os": "win32", "cpu": "x64" }, "sha512-hPt/bgL5cE+Qp+/TPHBqptcAgPzgj46mPcg/16zNUmbQk0j+mOEQV/+Lqu8QRtDV3Ek95Q6FeFITpuhl6OTsAA=="],

-    "@types/better-sqlite3": ["@types/better-sqlite3@7.6.13", "", { "dependencies": { "@types/node": "*" } }, "sha512-NMv9ASNARoKksWtsq/SHakpYAYnhBrQgGD8zkLYk/jaK8jUGn08CfEdTRgYhMypUQAfzSP8W6gNLe0q19/t4VA=="],
-
    "@types/chai": ["@types/chai@5.2.3", "", { "dependencies": { "@types/deep-eql": "*", "assertion-error": "^2.0.1" } }, "sha512-Mw558oeA9fFbv65/y4mHtXDs9bPnFMZAL/jxdPFUpOHHIXX91mcgEHbS5Lahr+pwZFR8A7GQleRWeI6cGFC2UA=="],

    "@types/deep-eql": ["@types/deep-eql@4.0.2", "", {}, "sha512-c9h9dVVMigMPc4bwTvC5dxqtqJZwQPePsWjPlpSOnojbor6pGqdk541lfA7AqFQr5pB1BRdq0juY9db81BwyFw=="],
@@ -165,16 +161,6 @@

    "aws-ssl-profiles": ["aws-ssl-profiles@1.1.2", "", {}, "sha512-NZKeq9AfyQvEeNlN0zSYAaWrmBffJh3IELMZfRpJVWgrpEbtEpnjvzqBPf+mxoI287JohRDoa+/nsfqqiZmF6g=="],

-    "base64-js": ["base64-js@1.5.1", "", {}, "sha512-AKpaYlHn8t4SVbOHCy+b5+KKgvR4vrsD8vbvrbiQJps7fKDTkjkDry6ji0rUJjC0kzbNePLwzxq8iypo41qeWA=="],
-
-    "better-sqlite3": ["better-sqlite3@12.9.0", "", { "dependencies": { "bindings": "^1.5.0", "prebuild-install": "^7.1.1" } }, "sha512-wqUv4Gm3toFpHDQmaKD4QhZm3g1DjUBI0yzS4UBl6lElUmXFYdTQmmEDpAFa5o8FiFiymURypEnfVHzILKaxqQ=="],
-
-    "bindings": ["bindings@1.5.0", "", { "dependencies": { "file-uri-to-path": "1.0.0" } }, "sha512-p2q/t/mhvuOj/UeLlV6566GD/guowlr0hHxClI0W9m7MWYkL1F0hLo+0Aexs9HSPCtR1SXQ0TD3MMKrXZajbiQ=="],
-
-    "bl": ["bl@4.1.0", "", { "dependencies": { "buffer": "^5.5.0", "inherits": "^2.0.4", "readable-stream": "^3.4.0" } }, "sha512-1W07cM9gS6DcLperZfFSj+bWLtaPGSOHWhPiGzXmvVJbRLdG82sH/Kn8EtW1VqWVA54AKf2h5k5BbnIbwF3h6w=="],
-
-    "buffer": ["buffer@5.7.1", "", { "dependencies": { "base64-js": "^1.3.1", "ieee754": "^1.1.13" } }, "sha512-EHcyIPBQ4BSGlvjB16k5KgAJ27CIsHY/2JBmCRReo48y9rQ3MaUzWX3KVlBa4U7MyX02HdVj0K7C3WaB3ju7FQ=="],
-
    "bundle-require": ["bundle-require@5.1.0", "", { "dependencies": { "load-tsconfig": "^0.2.3" }, "peerDependencies": { "esbuild": ">=0.18" } }, "sha512-3WrrOuZiyaaZPWiEt4G3+IffISVC9HYlWueJEBWED4ZH4aIAC2PnkdnuRrR94M+w6yGWn4AglWtJtBI8YqvgoA=="],

    "cac": ["cac@6.7.14", "", {}, "sha512-b6Ilus+c3RrdDk+JhLKUAQfzzgLEPy6wcXqS7f/xe1EETvsDP6GORG7SFuOs6cID5YkqchW/LXZbX5bc8j7ZcQ=="],
@@ -185,8 +171,6 @@

    "chokidar": ["chokidar@4.0.3", "", { "dependencies": { "readdirp": "^4.0.1" } }, "sha512-Qgzu8kfBvo+cA4962jnP1KkS6Dop5NS6g7R5LFYJr4b8Ub94PPQXUksCw9PvXoeXPRRddRNC5C1JQUR2SMGtnA=="],

-    "chownr": ["chownr@1.1.4", "", {}, "sha512-jJ0bqzaylmJtVnNgzTeSOs8DPavpbYgEr/b0YL8/2GO3xJEhInFmhKMUnEJQjZumK7KXGFhUy89PrsJWlakBVg=="],
-
    "commander": ["commander@4.1.1", "", {}, "sha512-NOKm8xhkzAjzFx8B2v5OAHT+u5pRQc2UCa2Vq9jYL/31o2wi9mxBA7LIFs3sV5VSC49z6pEhfbMULvShKj26WA=="],

    "confbox": ["confbox@0.1.8", "", {}, "sha512-RMtmw0iFkeR4YV+fUOSucriAQNb9g8zFR52MWCtl+cCZOFRNL6zeB395vPzFhEjjn4fMxXudmELnl/KF/WrK6w=="],
@@ -195,50 +179,28 @@

    "debug": ["debug@4.4.3", "", { "dependencies": { "ms": "^2.1.3" } }, "sha512-RGwwWnwQvkVfavKVt22FGLw+xYSdzARwm0ru6DhTVA3umU5hZc28V3kO4stgYryrTlLpuvgI9GiijltAjNbcqA=="],

-    "decompress-response": ["decompress-response@6.0.0", "", { "dependencies": { "mimic-response": "^3.1.0" } }, "sha512-aW35yZM6Bb/4oJlZncMH2LCoZtJXTRxES17vE3hoRiowU2kWHaJKFkSBDnDR+cm9J+9QhXmREyIfv0pji9ejCQ=="],
-
    "deep-eql": ["deep-eql@5.0.2", "", {}, "sha512-h5k/5U50IJJFpzfL6nO9jaaumfjO/f2NjK/oYB2Djzm4p9L+3T9qWpZqZ2hAbLPuuYq9wrU08WQyBTL5GbPk5Q=="],

-    "deep-extend": ["deep-extend@0.6.0", "", {}, "sha512-LOHxIOaPYdHlJRtCQfDIVZtfw/ufM8+rVj649RIHzcm/vGwQRXFt6OPqIFWsm2XEMrNIEtWR64sY1LEKD2vAOA=="],
-
    "denque": ["denque@2.1.0", "", {}, "sha512-HVQE3AAb/pxF8fQAoiqpvg9i3evqug3hoiwakOyZAwJm+6vZehbkYXZ0l4JxS+I3QxM97v5aaRNhj8v5oBhekw=="],

-    "detect-libc": ["detect-libc@2.1.2", "", {}, "sha512-Btj2BOOO83o3WyH59e8MgXsxEQVcarkUOpEYrubB0urwnN10yQ364rsiByU11nZlqWYZm05i/of7io4mzihBtQ=="],
-
-    "end-of-stream": ["end-of-stream@1.4.5", "", { "dependencies": { "once": "^1.4.0" } }, "sha512-ooEGc6HP26xXq/N+GCGOT0JKCLDGrq2bQUZrQ7gyrJiZANJ/8YDTxTpQBXGMn+WbIQXNVpyWymm7KYVICQnyOg=="],
-
    "es-module-lexer": ["es-module-lexer@1.7.0", "", {}, "sha512-jEQoCwk8hyb2AZziIOLhDqpm5+2ww5uIE6lkO/6jcOCusfk6LhMHpXXfBLXTZ7Ydyt0j4VoUQv6uGNYbdW+kBA=="],

    "esbuild": ["esbuild@0.27.7", "", { "optionalDependencies": { "@esbuild/aix-ppc64": "0.27.7", "@esbuild/android-arm": "0.27.7", "@esbuild/android-arm64": "0.27.7", "@esbuild/android-x64": "0.27.7", "@esbuild/darwin-arm64": "0.27.7", "@esbuild/darwin-x64": "0.27.7", "@esbuild/freebsd-arm64": "0.27.7", "@esbuild/freebsd-x64": "0.27.7", "@esbuild/linux-arm": "0.27.7", "@esbuild/linux-arm64": "0.27.7", "@esbuild/linux-ia32": "0.27.7", "@esbuild/linux-loong64": "0.27.7", "@esbuild/linux-mips64el": "0.27.7", "@esbuild/linux-ppc64": "0.27.7", "@esbuild/linux-riscv64": "0.27.7", "@esbuild/linux-s390x": "0.27.7", "@esbuild/linux-x64": "0.27.7", "@esbuild/netbsd-arm64": "0.27.7", "@esbuild/netbsd-x64": "0.27.7", "@esbuild/openbsd-arm64": "0.27.7", "@esbuild/openbsd-x64": "0.27.7", "@esbuild/openharmony-arm64": "0.27.7", "@esbuild/sunos-x64": "0.27.7", "@esbuild/win32-arm64": "0.27.7", "@esbuild/win32-ia32": "0.27.7", "@esbuild/win32-x64": "0.27.7" }, "bin": { "esbuild": "bin/esbuild" } }, "sha512-IxpibTjyVnmrIQo5aqNpCgoACA/dTKLTlhMHihVHhdkxKyPO1uBBthumT0rdHmcsk9uMonIWS0m4FljWzILh3w=="],

    "estree-walker": ["estree-walker@3.0.3", "", { "dependencies": { "@types/estree": "^1.0.0" } }, "sha512-7RUKfXgSMMkzt6ZuXmqapOurLGPPfgj6l9uRZ7lRGolvk0y2yocc35LdcxKC5PQZdn2DMqioAQ2NoWcrTKmm6g=="],

-    "expand-template": ["expand-template@2.0.3", "", {}, "sha512-XYfuKMvj4O35f/pOXLObndIRvyQ+/+6AhODh+OKWj9S9498pHHn/IMszH+gt0fBCRWMNfk1ZSp5x3AifmnI2vg=="],
-
    "expect-type": ["expect-type@1.3.0", "", {}, "sha512-knvyeauYhqjOYvQ66MznSMs83wmHrCycNEN6Ao+2AeYEfxUIkuiVxdEa1qlGEPK+We3n0THiDciYSsCcgW/DoA=="],

    "fdir": ["fdir@6.5.0", "", { "peerDependencies": { "picomatch": "^3 || ^4" }, "optionalPeers": ["picomatch"] }, "sha512-tIbYtZbucOs0BRGqPJkshJUYdL+SDH7dVM8gjy+ERp3WAUjLEFJE+02kanyHtwjWOnwrKYBiwAmM0p4kLJAnXg=="],

-    "file-uri-to-path": ["file-uri-to-path@1.0.0", "", {}, "sha512-0Zt+s3L7Vf1biwWZ29aARiVYLx7iMGnEUl9x33fbB/j3jR81u/O2LbqK+Bm1CDSNDKVtJ/YjwY7TUd5SkeLQLw=="],
-
    "fix-dts-default-cjs-exports": ["fix-dts-default-cjs-exports@1.0.1", "", { "dependencies": { "magic-string": "^0.30.17", "mlly": "^1.7.4", "rollup": "^4.34.8" } }, "sha512-pVIECanWFC61Hzl2+oOCtoJ3F17kglZC/6N94eRWycFgBH35hHx0Li604ZIzhseh97mf2p0cv7vVrOZGoqhlEg=="],

-    "fs-constants": ["fs-constants@1.0.0", "", {}, "sha512-y6OAwoSIf7FyjMIv94u+b5rdheZEjzR63GTyZJm5qh4Bi+2YgwLCcI/fPFZkL5PSixOt6ZNKm+w+Hfp/Bciwow=="],
-
    "fsevents": ["fsevents@2.3.3", "", { "os": "darwin" }, "sha512-5xoDfX+fL7faATnagmWPpbFtwh/R77WmMMqqHGS65C3vvB0YHrgF+B1YmZ3441tMj5n63k0212XNoJwzlhffQw=="],

    "generate-function": ["generate-function@2.3.1", "", { "dependencies": { "is-property": "^1.0.2" } }, "sha512-eeB5GfMNeevm/GRYq20ShmsaGcmI81kIX2K9XQx5miC8KdHaC6Jm0qQ8ZNeGOi7wYB8OsdxKs+Y2oVuTFuVwKQ=="],

-    "github-from-package": ["github-from-package@0.0.0", "", {}, "sha512-SyHy3T1v2NUXn29OsWdxmK6RwHD+vkj3v8en8AOBZ1wBQ/hCAQ5bAQTD02kW4W9tUp/3Qh6J8r9EvntiyCmOOw=="],
-
    "iconv-lite": ["iconv-lite@0.7.2", "", { "dependencies": { "safer-buffer": ">= 2.1.2 < 3.0.0" } }, "sha512-im9DjEDQ55s9fL4EYzOAv0yMqmMBSZp6G0VvFyTMPKWxiSBHUj9NW/qqLmXUwXrrM7AvqSlTCfvqRb0cM8yYqw=="],

-    "ieee754": ["ieee754@1.2.1", "", {}, "sha512-dcyqhDvX1C46lXZcVqCpK+FtMRQVdIMN6/Df5js2zouUsqG7I6sFxitIC+7KYK29KdXOLHdu9zL4sFnoVQnqaA=="],
-
-    "inherits": ["inherits@2.0.4", "", {}, "sha512-k/vGaX4/Yla3WzyMCvTQOXYeIHvqOKtnqBduzTHpzpQZzAskKMhZ2K+EnBiSM9zGSoIFeMpXKxa4dYeZIQqewQ=="],
-
-    "ini": ["ini@1.3.8", "", {}, "sha512-JV/yugV2uzW5iMRSiZAyDtQd+nxtUnjeLt0acNdw98kKLrvuRVyB80tsREOE7yvGVgalhZ6RNXCmEHkUKBKxew=="],
-
    "is-property": ["is-property@1.0.2", "", {}, "sha512-Ks/IoX00TtClbGQr4TWXemAnktAQvYB7HzcCxDGqEZU6oCmb2INHuOoKxbtR+HFkmYWBKv/dOZtGRiAjDhj92g=="],

    "joycon": ["joycon@3.1.1", "", {}, "sha512-34wB/Y7MW7bzjKRjUKTa46I2Z7eV62Rkhva+KkopW7Qvv/OSWBqvkSY7vusOPrNuZcUG3tApvdVgNB8POj3SPw=="],
@@ -261,12 +223,6 @@

    "magic-string": ["magic-string@0.30.21", "", { "dependencies": { "@jridgewell/sourcemap-codec": "^1.5.5" } }, "sha512-vd2F4YUyEXKGcLHoq+TEyCjxueSeHnFxyyjNp80yg0XV4vUhnDer/lvvlqM/arB5bXQN5K2/3oinyCRyx8T2CQ=="],

-    "mimic-response": ["mimic-response@3.1.0", "", {}, "sha512-z0yWI+4FDrrweS8Zmt4Ej5HdJmky15+L2e6Wgn3+iK5fWzb6T3fhNFq2+MeTRb064c6Wr4N/wv0DzQTjNzHNGQ=="],
-
-    "minimist": ["minimist@1.2.8", "", {}, "sha512-2yyAR8qBkN3YuheJanUpWC5U3bb5osDywNB8RzDVlDwDHbocAJveqqj1u8+SVD7jkWT4yvsHCpWqqWqAxb0zCA=="],
-
-    "mkdirp-classic": ["mkdirp-classic@0.5.3", "", {}, "sha512-gKLcREMhtuZRwRAfqP3RFW+TK4JqApVBtOIftVgjuABpAtpxhPGaDcfvbhNvD0B8iD1oUr/txX35NjcaY6Ns/A=="],
-
    "mlly": ["mlly@1.8.2", "", { "dependencies": { "acorn": "^8.16.0", "pathe": "^2.0.3", "pkg-types": "^1.3.1", "ufo": "^1.6.3" } }, "sha512-d+ObxMQFmbt10sretNDytwt85VrbkhhUA/JBGm1MPaWJ65Cl4wOgLaB1NYvJSZ0Ef03MMEU/0xpPMXUIQ29UfA=="],

    "ms": ["ms@2.1.3", "", {}, "sha512-6FlzubTLZG3J2a/NVCAleEhjzq5oxgHyaCU9yYXvcLsvoVaHJq/s5xXI6/XXP6tz7R9xAOtHnSO/tXtF3WRTlA=="],
@@ -279,14 +235,8 @@

    "nanoid": ["nanoid@3.3.12", "", { "bin": { "nanoid": "bin/nanoid.cjs" } }, "sha512-ZB9RH/39qpq5Vu6Y+NmUaFhQR6pp+M2Xt76XBnEwDaGcVAqhlvxrl3B2bKS5D3NH3QR76v3aSrKaF/Kiy7lEtQ=="],

-    "napi-build-utils": ["napi-build-utils@2.0.0", "", {}, "sha512-GEbrYkbfF7MoNaoh2iGG84Mnf/WZfB0GdGEsM8wz7Expx/LlWf5U8t9nvJKXSp3qr5IsEbK04cBGhol/KwOsWA=="],
-
-    "node-abi": ["node-abi@3.92.0", "", { "dependencies": { "semver": "^7.3.5" } }, "sha512-KdHvFWZjEKDf0cakgFjebl371GPsISX2oZHcuyKqM7DtogIsHrqKeLTo8wBHxaXRAQlY2PsPlZmfo+9ZCxEREQ=="],
-
    "object-assign": ["object-assign@4.1.1", "", {}, "sha512-rJgTQnkUnH1sFw8yT6VSU3zD3sWmu6sZhIseY8VX+GRu3P6F7Fu+JNDoXfklElbLJSnc3FUQHVe4cU5hj+BcUg=="],

-    "once": ["once@1.4.0", "", { "dependencies": { "wrappy": "1" } }, "sha512-lNaJgI+2Q5URQBkccEKHTQOPaXdUxnZZElQTZY0MFUAuaEqe1E+Nyvgdz/aIyNi6Z9MzO5dv1H8n58/GELp3+w=="],
-
    "pathe": ["pathe@2.0.3", "", {}, "sha512-WUjGcAqP1gQacoQe+OBJsFA7Ld4DyXuUIjZ5cc75cLHvJ7dtNsTugphxIADwspS+AraAUePCKrSVtPLFj/F88w=="],

    "pathval": ["pathval@2.0.1", "", {}, "sha512-//nshmD55c46FuFw26xV/xFAaB5HF9Xdap7HJBBnrKdAd6/GxDBaNA1870O79+9ueg61cZLSVc+OaFlfmObYVQ=="],
@@ -327,32 +277,16 @@

    "postgres-interval": ["postgres-interval@1.2.0", "", { "dependencies": { "xtend": "^4.0.0" } }, "sha512-9ZhXKM/rw350N1ovuWHbGxnGh/SNJ4cnxHiM0rxE4VN41wsg8P8zWn9hv/buK00RP4WvlOyr/RBDiptyxVbkZQ=="],

-    "prebuild-install": ["prebuild-install@7.1.3", "", { "dependencies": { "detect-libc": "^2.0.0", "expand-template": "^2.0.3", "github-from-package": "0.0.0", "minimist": "^1.2.3", "mkdirp-classic": "^0.5.3", "napi-build-utils": "^2.0.0", "node-abi": "^3.3.0", "pump": "^3.0.0", "rc": "^1.2.7", "simple-get": "^4.0.0", "tar-fs": "^2.0.0", "tunnel-agent": "^0.6.0" }, "bin": { "prebuild-install": "bin.js" } }, "sha512-8Mf2cbV7x1cXPUILADGI3wuhfqWvtiLA1iclTDbFRZkgRQS0NqsPZphna9V+HyTEadheuPmjaJMsbzKQFOzLug=="],
-
-    "pump": ["pump@3.0.4", "", { "dependencies": { "end-of-stream": "^1.1.0", "once": "^1.3.1" } }, "sha512-VS7sjc6KR7e1ukRFhQSY5LM2uBWAUPiOPa/A3mkKmiMwSmRFUITt0xuj+/lesgnCv+dPIEYlkzrcyXgquIHMcA=="],
-
-    "rc": ["rc@1.2.8", "", { "dependencies": { "deep-extend": "^0.6.0", "ini": "~1.3.0", "minimist": "^1.2.0", "strip-json-comments": "~2.0.1" }, "bin": { "rc": "./cli.js" } }, "sha512-y3bGgqKj3QBdxLbLkomlohkvsA8gdAiUQlSBJnBhfn+BPxg4bc62d8TcBW15wavDfgexCgccckhcZvywyQYPOw=="],
-
-    "readable-stream": ["readable-stream@3.6.2", "", { "dependencies": { "inherits": "^2.0.3", "string_decoder": "^1.1.1", "util-deprecate": "^1.0.1" } }, "sha512-9u/sniCrY3D5WdsERHzHE4G2YCXqoG5FTHUiCC4SIbr6XcLZBY05ya9EKjYek9O5xOAwjGq+1JdGBAS7Q9ScoA=="],
-
    "readdirp": ["readdirp@4.1.2", "", {}, "sha512-GDhwkLfywWL2s6vEjyhri+eXmfH6j1L7JE27WhqLeYzoh/A3DBaYGEj2H/HFZCn/kMfim73FXxEJTw06WtxQwg=="],

    "resolve-from": ["resolve-from@5.0.0", "", {}, "sha512-qYg9KP24dD5qka9J47d0aVky0N+b4fTU89LN9iDnjB5waksiC49rvMB0PrUJQGoTmH50XPiqOvAjDfaijGxYZw=="],

    "rollup": ["rollup@4.60.3", "", { "dependencies": { "@types/estree": "1.0.8" }, "optionalDependencies": { "@rollup/rollup-android-arm-eabi": "4.60.3", "@rollup/rollup-android-arm64": "4.60.3", "@rollup/rollup-darwin-arm64": "4.60.3", "@rollup/rollup-darwin-x64": "4.60.3", "@rollup/rollup-freebsd-arm64": "4.60.3", "@rollup/rollup-freebsd-x64": "4.60.3", "@rollup/rollup-linux-arm-gnueabihf": "4.60.3", "@rollup/rollup-linux-arm-musleabihf": "4.60.3", "@rollup/rollup-linux-arm64-gnu": "4.60.3", "@rollup/rollup-linux-arm64-musl": "4.60.3", "@rollup/rollup-linux-loong64-gnu": "4.60.3", "@rollup/rollup-linux-loong64-musl": "4.60.3", "@rollup/rollup-linux-ppc64-gnu": "4.60.3", "@rollup/rollup-linux-ppc64-musl": "4.60.3", "@rollup/rollup-linux-riscv64-gnu": "4.60.3", "@rollup/rollup-linux-riscv64-musl": "4.60.3", "@rollup/rollup-linux-s390x-gnu": "4.60.3", "@rollup/rollup-linux-x64-gnu": "4.60.3", "@rollup/rollup-linux-x64-musl": "4.60.3", "@rollup/rollup-openbsd-x64": "4.60.3", "@rollup/rollup-openharmony-arm64": "4.60.3", "@rollup/rollup-win32-arm64-msvc": "4.60.3", "@rollup/rollup-win32-ia32-msvc": "4.60.3", "@rollup/rollup-win32-x64-gnu": "4.60.3", "@rollup/rollup-win32-x64-msvc": "4.60.3", "fsevents": "~2.3.2" }, "bin": { "rollup": "dist/bin/rollup" } }, "sha512-pAQK9HalE84QSm4Po3EmWIZPd3FnjkShVkiMlz1iligWYkWQ7wHYd1PF/T7QZ5TVSD6uSTon5gBVMSM4JfBV+A=="],

-    "safe-buffer": ["safe-buffer@5.2.1", "", {}, "sha512-rp3So07KcdmmKbGvgaNxQSJr7bGVSVk5S9Eq1F+ppbRo70+YeaDxkw5Dd8NPN+GD6bjnYm2VuPuCXmpuYvmCXQ=="],
-
    "safer-buffer": ["safer-buffer@2.1.2", "", {}, "sha512-YZo3K82SD7Riyi0E1EQPojLz7kpepnSQI9IyPbHHg1XXXevb5dJI7tpyN2ADxGcQbHG7vcyRHk0cbwqcQriUtg=="],

-    "semver": ["semver@7.8.0", "", { "bin": { "semver": "bin/semver.js" } }, "sha512-AcM7dV/5ul4EekoQ29Agm5vri8JNqRyj39o0qpX6vDF2GZrtutZl5RwgD1XnZjiTAfncsJhMI48QQH3sN87YNA=="],
-
    "siginfo": ["siginfo@2.0.0", "", {}, "sha512-ybx0WO1/8bSBLEWXZvEd7gMW3Sn3JFlW3TvX1nREbDLRNQNaeNN8WK0meBwPdAaOI7TtRRRJn/Es1zhrrCHu7g=="],

-    "simple-concat": ["simple-concat@1.0.1", "", {}, "sha512-cSFtAPtRhljv69IK0hTVZQ+OfE9nePi/rtJmw5UjHeVyVroEqJXP1sFztKUy1qU+xvz3u/sfYJLa947b7nAN2Q=="],
-
-    "simple-get": ["simple-get@4.0.1", "", { "dependencies": { "decompress-response": "^6.0.0", "once": "^1.3.1", "simple-concat": "^1.0.0" } }, "sha512-brv7p5WgH0jmQJr1ZDDfKDOSeWWg+OVypG99A/5vYGPqJ6pxiaHLy8nxtFjBA7oMa01ebA9gfh1uMCFqOuXxvA=="],
-
    "source-map": ["source-map@0.7.6", "", {}, "sha512-i5uvt8C3ikiWeNZSVZNWcfZPItFQOsYTUAOkcUPGd8DqDy1uOUikjt5dG+uRlwyvR108Fb9DOd4GvXfT0N2/uQ=="],

    "source-map-js": ["source-map-js@1.2.1", "", {}, "sha512-UXWMKhLOwVKb728IUtQPXxfYU+usdybtUrK/8uGE8CQMvrhOpwvzDBwj0QhSL7MQc7vIsISBG8VQ8+IDQxpfQA=="],
@@ -365,18 +299,10 @@

    "std-env": ["std-env@3.10.0", "", {}, "sha512-5GS12FdOZNliM5mAOxFRg7Ir0pWz8MdpYm6AY6VPkGpbA7ZzmbzNcBJQ0GPvvyWgcY7QAhCgf9Uy89I03faLkg=="],

-    "string_decoder": ["string_decoder@1.3.0", "", { "dependencies": { "safe-buffer": "~5.2.0" } }, "sha512-hkRX8U1WjJFd8LsDJ2yQ/wWWxaopEsABU1XfkM8A+j0+85JAGppt16cr1Whg6KIbb4okU6Mql6BOj+uup/wKeA=="],
-
-    "strip-json-comments": ["strip-json-comments@2.0.1", "", {}, "sha512-4gB8na07fecVVkOI6Rs4e7T6NOTki5EmL7TUduTs6bu3EdnSycntVJ4re8kgZA+wx9IueI2Y11bfbgwtzuE0KQ=="],
-
    "strip-literal": ["strip-literal@3.1.0", "", { "dependencies": { "js-tokens": "^9.0.1" } }, "sha512-8r3mkIM/2+PpjHoOtiAW8Rg3jJLHaV7xPwG+YRGrv6FP0wwk/toTpATxWYOW0BKdWwl82VT2tFYi5DlROa0Mxg=="],

    "sucrase": ["sucrase@3.35.1", "", { "dependencies": { "@jridgewell/gen-mapping": "^0.3.2", "commander": "^4.0.0", "lines-and-columns": "^1.1.6", "mz": "^2.7.0", "pirates": "^4.0.1", "tinyglobby": "^0.2.11", "ts-interface-checker": "^0.1.9" }, "bin": { "sucrase": "bin/sucrase", "sucrase-node": "bin/sucrase-node" } }, "sha512-DhuTmvZWux4H1UOnWMB3sk0sbaCVOoQZjv8u1rDoTV0HTdGem9hkAZtl4JZy8P2z4Bg0nT+YMeOFyVr4zcG5Tw=="],

-    "tar-fs": ["tar-fs@2.1.4", "", { "dependencies": { "chownr": "^1.1.1", "mkdirp-classic": "^0.5.2", "pump": "^3.0.0", "tar-stream": "^2.1.4" } }, "sha512-mDAjwmZdh7LTT6pNleZ05Yt65HC3E+NiQzl672vQG38jIrehtJk/J3mNwIg+vShQPcLF/LV7CMnDW6vjj6sfYQ=="],
-
-    "tar-stream": ["tar-stream@2.2.0", "", { "dependencies": { "bl": "^4.0.3", "end-of-stream": "^1.4.1", "fs-constants": "^1.0.0", "inherits": "^2.0.3", "readable-stream": "^3.1.1" } }, "sha512-ujeqbceABgwMZxEJnk2HDY2DlnUZ+9oEcb1KzTVfYHio0UE6dG71n60d8D2I4qNvleWrrXpmjpt7vZeF1LnMZQ=="],
-
    "thenify": ["thenify@3.3.1", "", { "dependencies": { "any-promise": "^1.0.0" } }, "sha512-RVZSIV5IG10Hk3enotrhvz0T9em6cyHBLkH/YAZuKqd8hRkKhSfCGIcP2KUY0EPxndzANBmNllzWPwak+bheSw=="],

    "thenify-all": ["thenify-all@1.6.0", "", { "dependencies": { "thenify": ">= 3.1.0 < 4" } }, "sha512-RNxQH/qI8/t3thXJDwcstUO4zeqo64+Uy/+sNVRBx4Xn2OX+OZ9oP+iJnNFqplFra2ZUVeKCSa2oVWi3T4uVmA=="],
@@ -399,16 +325,12 @@

    "tsup": ["tsup@8.5.1", "", { "dependencies": { "bundle-require": "^5.1.0", "cac": "^6.7.14", "chokidar": "^4.0.3", "consola": "^3.4.0", "debug": "^4.4.0", "esbuild": "^0.27.0", "fix-dts-default-cjs-exports": "^1.0.0", "joycon": "^3.1.1", "picocolors": "^1.1.1", "postcss-load-config": "^6.0.1", "resolve-from": "^5.0.0", "rollup": "^4.34.8", "source-map": "^0.7.6", "sucrase": "^3.35.0", "tinyexec": "^0.3.2", "tinyglobby": "^0.2.11", "tree-kill": "^1.2.2" }, "peerDependencies": { "@microsoft/api-extractor": "^7.36.0", "@swc/core": "^1", "postcss": "^8.4.12", "typescript": ">=4.5.0" }, "optionalPeers": ["@microsoft/api-extractor", "@swc/core", "postcss", "typescript"], "bin": { "tsup": "dist/cli-default.js", "tsup-node": "dist/cli-node.js" } }, "sha512-xtgkqwdhpKWr3tKPmCkvYmS9xnQK3m3XgxZHwSUjvfTjp7YfXe5tT3GgWi0F2N+ZSMsOeWeZFh7ZZFg5iPhing=="],

-    "tunnel-agent": ["tunnel-agent@0.6.0", "", { "dependencies": { "safe-buffer": "^5.0.1" } }, "sha512-McnNiV1l8RYeY8tBgEpuodCC1mLUdbSN+CYBL7kJsJNInOP8UjDDEwdk6Mw60vdLLrr5NHKZhMAOSrR2NZuQ+w=="],
-
    "typescript": ["typescript@5.9.3", "", { "bin": { "tsc": "bin/tsc", "tsserver": "bin/tsserver" } }, "sha512-jl1vZzPDinLr9eUt3J/t7V6FgNEw9QjvBPdysz9KfQDD41fQrC2Y4vKQdiaUpFT4bXlb1RHhLpp8wtm6M5TgSw=="],

    "ufo": ["ufo@1.6.4", "", {}, "sha512-JFNbkD1Svwe0KvGi8GOeLcP4kAWQ609twvCdcHxq1oSL8svv39ZuSvajcD8B+5D0eL4+s1Is2D/O6KN3qcTeRA=="],

    "undici-types": ["undici-types@7.16.0", "", {}, "sha512-Zz+aZWSj8LE6zoxD+xrjh4VfkIG8Ya6LvYkZqtUQGJPZjYl53ypCaUwWqo7eI0x66KBGeRo+mlBEkMSeSZ38Nw=="],

-    "util-deprecate": ["util-deprecate@1.0.2", "", {}, "sha512-EPD5q1uXyFxJpCrLnCc1nHnq3gOa6DZBocAIiI2TaSCA7VCJ1UJDMagCzIkXNsUYfD1daK//LTEQ8xiIbrHtcw=="],
-
    "vite": ["vite@7.3.3", "", { "dependencies": { "esbuild": "^0.27.0", "fdir": "^6.5.0", "picomatch": "^4.0.3", "postcss": "^8.5.6", "rollup": "^4.43.0", "tinyglobby": "^0.2.15" }, "optionalDependencies": { "fsevents": "~2.3.3" }, "peerDependencies": { "@types/node": "^20.19.0 || >=22.12.0", "jiti": ">=1.21.0", "less": "^4.0.0", "lightningcss": "^1.21.0", "sass": "^1.70.0", "sass-embedded": "^1.70.0", "stylus": ">=0.54.8", "sugarss": "^5.0.0", "terser": "^5.16.0", "tsx": "^4.8.1", "yaml": "^2.4.2" }, "optionalPeers": ["@types/node", "jiti", "less", "lightningcss", "sass", "sass-embedded", "stylus", "sugarss", "terser", "tsx", "yaml"], "bin": { "vite": "bin/vite.js" } }, "sha512-/4XH147Ui7OGTjg3HbdWe5arnZQSbfuRzdr9Ec7TQi5I7R+ir0Rlc9GIvD4v0XZurELqA035KVXJXpR61xhiTA=="],

    "vite-node": ["vite-node@3.2.4", "", { "dependencies": { "cac": "^6.7.14", "debug": "^4.4.1", "es-module-lexer": "^1.7.0", "pathe": "^2.0.3", "vite": "^5.0.0 || ^6.0.0 || ^7.0.0-0" }, "bin": { "vite-node": "vite-node.mjs" } }, "sha512-EbKSKh+bh1E1IFxeO0pg1n4dvoOTt0UDiXMd/qn++r98+jPO1xtJilvXldeuQ8giIB5IkpjCgMleHMNEsGH6pg=="],
@@ -417,8 +339,6 @@

    "why-is-node-running": ["why-is-node-running@2.3.0", "", { "dependencies": { "siginfo": "^2.0.0", "stackback": "0.0.2" }, "bin": { "why-is-node-running": "cli.js" } }, "sha512-hUrmaWBdVDcxvYqnyh09zunKzROWjbZTiNy8dBEjkS7ehEDQibXJ7XvlmtbwuTclUiIyN+CyXQD4Vmko8fNm8w=="],

-    "wrappy": ["wrappy@1.0.2", "", {}, "sha512-l4Sp/DRseor9wL6EvV2+TuQn63dMkPjZ/sp9XkghTEbV9KlPS1xUsZ3u7/IQO4wxtcFB4bgpQPRcR3QCvezPcQ=="],
-
    "xtend": ["xtend@4.0.2", "", {}, "sha512-LKYU1iAXJXUgAXn9URjiu+MWhyUXHsvfp7mcuYm9dSUKK0/CjtrUwFAxD82/mCWbtLsGjFIad0wIsod4zrTAEQ=="],

    "estree-walker/@types/estree": ["@types/estree@1.0.9", "", {}, "sha512-GhdPgy1el4/ImP05X05Uw4cw2/M93BCUmnEvWZNStlCzEKME4Fkk+YpoA5OiHNQmoS7Cafb8Xa3Pya8m1Qrzeg=="],
--- a/docs/plans/2026-05-11-identitydb-foundation.md
+++ b/docs/plans/2026-05-11-identitydb-foundation.md
@@ -6,7 +6,7 @@

 **Architecture:** IdentityDB will use a layered architecture: a storage layer based on Kysely + dialect adapters, a domain layer for topics/facts/links, and a service layer that exposes ergonomic high-level APIs for querying and ingesting memory. Schema initialization will be automatic and idempotent. AI-assisted ingestion will be abstracted behind a pluggable extractor interface so callers can use a small LLM or a deterministic extractor without coupling the core package to a specific model provider.

-**Tech Stack:** TypeScript, Bun, Node.js, Kysely, better-sqlite3, pg, mysql2, Vitest, tsup.
+**Tech Stack:** TypeScript, Bun, Node.js, Kysely, bun:sqlite, pg, mysql2, Vitest, tsup.

 ---

--- a/docs/plans/2026-05-11-identitydb-memory-expansion.md
+++ b/docs/plans/2026-05-11-identitydb-memory-expansion.md
@@ -6,7 +6,7 @@

 **Architecture:** Keep the relational core portable across SQLite, PostgreSQL, MySQL, and MariaDB by introducing dedicated extension tables: `topic_relations` for abstract/concrete hierarchy, `topic_aliases` for canonical topic resolution, and `fact_embeddings` for semantic indexing. Expose high-level APIs from `IdentityDB` while preserving DB-agnostic behavior by doing semantic scoring in the application layer first.

-**Tech Stack:** TypeScript, Bun, Node.js, Kysely, better-sqlite3, pg, mysql2, Vitest, tsup.
+**Tech Stack:** TypeScript, Bun, Node.js, Kysely, bun:sqlite, pg, mysql2, Vitest, tsup.

 ---

--- a/docs/plans/2026-05-11-identitydb-space-isolation.md
+++ b/docs/plans/2026-05-11-identitydb-space-isolation.md
@@ -0,0 +1,157 @@
+# IdentityDB Space Isolation Implementation Plan
+
+> **For Hermes:** Use the `writing-plans` and `test-driven-development` skills. Implement this feature in small TDD steps with meaningful commits.
+
+**Goal:** Add first-class memory spaces so callers can keep unrelated topic/fact graphs isolated from each other while still using one physical database.
+
+**Architecture:** Introduce a `spaces` table plus `space_id` scoping on the canonical topic/fact records that define graph ownership. Treat the unnamed/default behavior as a built-in `default` space so existing API usage keeps working, while allowing any write/query path to target a named space explicitly.
+
+**Tech Stack:** TypeScript, Bun, Vitest, Kysely, SQLite/PostgreSQL/MySQL/MariaDB-compatible schema primitives.
+
+---
+
+## Requirements
+
+1. A caller must be able to write memory into independent spaces such as `A` and `B`.
+2. Topic lookups, alias resolution, hierarchy traversal, connected-topic queries, fact queries, ingestion, and semantic search must only see data from the requested space.
+3. Existing callers that do not specify a space must continue to work inside a built-in `default` space.
+4. Space names must be normalized/canonicalized similarly to topics.
+5. Documentation must explain both the isolation model and the default-space compatibility behavior.
+
+---
+
+## Task 1: Add failing tests for schema-level space support
+
+**Objective:** Define the storage contract for spaces and per-space uniqueness before implementation.
+
+**Files:**
+- Modify: `tests/migrations.test.ts`
+
+**Step 1: Write failing tests**
+- Assert that initialization creates a `spaces` table.
+- Assert that `topics`, `facts`, and `topic_aliases` now include `space_id`.
+- Assert that `spaces` includes `id`, `name`, `normalized_name`, `description`, `metadata`, `created_at`, `updated_at`.
+
+**Step 2: Run red test**
+- Run: `bun run test tests/migrations.test.ts`
+- Expect: failure because the schema does not yet contain space support.
+
+**Step 3: Commit later with implementation**
+- Do not commit yet; continue only after implementation turns the test green.
+
+---
+
+## Task 2: Add failing behavioral tests for isolated spaces
+
+**Objective:** Lock in the public API behavior for separate memory spaces.
+
+**Files:**
+- Modify: `tests/identity-db.test.ts`
+- Modify: `tests/queries.test.ts`
+- Modify: `tests/semantic-search.test.ts`
+- Optionally create: `tests/spaces.test.ts` if separation makes the scenarios clearer.
+
+**Step 1: Write failing tests**
+- Verify the same topic name can exist in two spaces without deduplicating together.
+- Verify facts added in `spaceName: 'A'` are invisible from `spaceName: 'B'`.
+- Verify alias resolution only resolves inside the same space.
+- Verify hierarchy parent/child traversal only stays within the same space.
+- Verify semantic search and duplicate-aware ingestion only search within the same space.
+- Verify callers that omit `spaceName` still operate in the `default` space.
+
+**Step 2: Run red tests**
+- Run the most targeted files first, then the whole suite slice.
+- Example: `bun run test tests/identity-db.test.ts tests/queries.test.ts tests/semantic-search.test.ts`
+- Expect: failure due to missing API fields and missing isolation logic.
+
+---
+
+## Task 3: Implement schema and type support
+
+**Objective:** Add the underlying data model required for spaces.
+
+**Files:**
+- Modify: `src/core/schema.ts`
+- Modify: `src/types/domain.ts`
+- Modify: `src/types/database.ts`
+- Modify: `src/core/migrations.ts`
+
+**Implementation notes:**
+- Add `SPACES_TABLE` and `SPACE_COLUMNS` constants.
+- Add `SpaceRecord` domain type.
+- Add `spaces` to `IdentityDatabaseSchema`.
+- Create the `spaces` table.
+- Add `space_id` columns to `topics`, `facts`, and `topic_aliases`.
+- Make topic uniqueness per-space, not global.
+- Make alias uniqueness per-space, not global.
+- Seed or upsert a built-in `default` space during initialization via normal application flow, not hard-coded SQL assumptions.
+
+**Verification:**
+- Re-run: `bun run test tests/migrations.test.ts`
+- Expect: green.
+
+---
+
+## Task 4: Implement space-aware API contracts and query helpers
+
+**Objective:** Thread `spaceName` through the high-level API and low-level query layer.
+
+**Files:**
+- Modify: `src/types/api.ts`
+- Modify: `src/ingestion/types.ts`
+- Modify: `src/queries/topics.ts`
+- Modify: `src/queries/facts.ts`
+- Modify: `src/core/identity-db.ts`
+- Modify: `src/index.ts` if new exported types are added
+
+**Implementation notes:**
+- Add public `Space` and `UpsertSpaceInput` types if needed.
+- Add optional `spaceName` on write/query inputs where the caller targets a graph.
+- Add helpers to resolve or create the requested space inside transactions.
+- Ensure all existing topic lookup helpers filter by `space_id`.
+- Ensure semantic search candidates are restricted to facts in the requested space.
+- Preserve existing no-space API calls by mapping them to `default`.
+
+**Verification:**
+- Re-run the failing behavior tests.
+- Expect: green for the new targeted tests.
+
+---
+
+## Task 5: Refine ergonomics and update documentation
+
+**Objective:** Make the feature understandable and safe to use.
+
+**Files:**
+- Modify: `README.md`
+- Optionally modify: wiki docs later if requested
+
+**Implementation notes:**
+- Document the default space behavior.
+- Add examples for `spaceName: 'A'` and `spaceName: 'B'`.
+- Explain that spaces are hard isolation boundaries for topic/fact traversal and semantic retrieval.
+
+**Verification:**
+- Run: `bun run test && bun run check && bun run build`
+- Confirm docs/examples align with the final public API.
+
+---
+
+## Suggested commit boundaries
+
+1. `docs: add IdentityDB space isolation plan`
+2. `test: specify isolated memory spaces`
+3. `feat: add space-aware memory graph isolation`
+4. `docs: document space-scoped memory usage`
+
+---
+
+## Acceptance checklist
+
+- [ ] `spaces` table exists.
+- [ ] Topics with the same normalized name can exist in different spaces.
+- [ ] Facts from one space do not appear in another space’s queries.
+- [ ] Alias and hierarchy traversal are space-aware.
+- [ ] Semantic search and duplicate detection are space-aware.
+- [ ] Existing callers still work via the `default` space.
+- [ ] Full test/build/typecheck suite passes.
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
  "name": "identitydb",
-  "version": "0.1.0",
+  "version": "0.2.1",
  "description": "TypeScript memory graph database wrapper for topics, facts, and AI-assisted ingestion.",
  "license": "MIT",
  "type": "module",
@@ -36,13 +36,11 @@
    "ai"
  ],
  "dependencies": {
-    "better-sqlite3": "^12.1.1",
    "kysely": "^0.28.8",
    "mysql2": "^3.15.3",
    "pg": "^8.16.0"
  },
  "devDependencies": {
-    "@types/better-sqlite3": "^7.6.13",
    "@types/node": "^24.0.0",
    "@types/pg": "^8.20.0",
    "tsup": "^8.5.0",
--- a/src/adapters/dialect.ts
+++ b/src/adapters/dialect.ts
@@ -1,4 +1,3 @@
-import Database from 'better-sqlite3';
 import { Kysely, MysqlDialect, PostgresDialect, SqliteDialect } from 'kysely';
 import { createPool as createMysqlPool } from 'mysql2';
 import { Pool as PostgresPool } from 'pg';
@@ -44,16 +43,183 @@ export interface DatabaseConnection {
  destroy: () => Promise<void>;
 }

+interface BunSqliteStatement {
+  columnNames: ReadonlyArray<string>;
+  all(parameters?: ReadonlyArray<unknown>): unknown[];
+  run(parameters?: ReadonlyArray<unknown>): {
+    changes: number | bigint;
+    lastInsertRowid: number | bigint;
+  };
+  iterate(parameters?: ReadonlyArray<unknown>): IterableIterator<unknown>;
+}
+
+interface BunSqliteDatabase {
+  close(): void;
+  exec(sql: string): void;
+  prepare(sql: string): BunSqliteStatement;
+}
+
+interface BunSqliteModule {
+  Database: {
+    open(filename: string, flags?: number): BunSqliteDatabase;
+  };
+  constants: {
+    SQLITE_OPEN_CREATE: number;
+    SQLITE_OPEN_MEMORY: number;
+    SQLITE_OPEN_READONLY: number;
+    SQLITE_OPEN_READWRITE: number;
+  };
+}
+
+interface NodeSqliteStatement {
+  all(...parameters: ReadonlyArray<unknown>): unknown[];
+  columns(): ReadonlyArray<unknown>;
+  iterate(...parameters: ReadonlyArray<unknown>): IterableIterator<unknown>;
+  run(...parameters: ReadonlyArray<unknown>): {
+    changes: number | bigint;
+    lastInsertRowid: number | bigint;
+  };
+}
+
+interface NodeSqliteDatabase {
+  close(): void;
+  exec(sql: string): void;
+  prepare(sql: string): NodeSqliteStatement;
+}
+
+interface NodeSqliteModule {
+  DatabaseSync: new (
+    filename: string,
+    options?: {
+      readOnly?: boolean;
+    },
+  ) => NodeSqliteDatabase;
+}
+
+interface KyselyCompatibleSqliteStatement {
+  readonly reader: boolean;
+  all(parameters: ReadonlyArray<unknown>): unknown[];
+  run(parameters: ReadonlyArray<unknown>): {
+    changes: number | bigint;
+    lastInsertRowid: number | bigint;
+  };
+  iterate(parameters: ReadonlyArray<unknown>): IterableIterator<unknown>;
+}
+
+interface KyselyCompatibleSqliteDatabase {
+  close(): void;
+  prepare(sql: string): KyselyCompatibleSqliteStatement;
+}
+
+const BUN_SQLITE_MODULE = 'bun:sqlite';
+const NODE_SQLITE_MODULE = 'node:sqlite';
+
+function createUnsupportedSqliteRuntimeError(): IdentityDBConfigurationError {
+  return new IdentityDBConfigurationError(
+    'SQLite connections now require a runtime with a built-in SQLite driver. Use Bun for bun:sqlite support, or Node 22+ for node:sqlite support.',
+  );
+}
+
+function isBunRuntime(): boolean {
+  return typeof globalThis === 'object' && 'Bun' in globalThis;
+}
+
+async function createBunSqliteDatabase(
+  config: SqliteConnectionConfig,
+  bunSqliteModule?: BunSqliteModule,
+): Promise<KyselyCompatibleSqliteDatabase> {
+  const bunSqlite = bunSqliteModule
+    ?? ((await import(BUN_SQLITE_MODULE).catch(() => {
+      throw createUnsupportedSqliteRuntimeError();
+    })) as BunSqliteModule);
+
+  const flags = config.readonly
+    ? bunSqlite.constants.SQLITE_OPEN_READONLY
+    : bunSqlite.constants.SQLITE_OPEN_READWRITE
+        | bunSqlite.constants.SQLITE_OPEN_CREATE
+        | (config.filename === ':memory:' ? bunSqlite.constants.SQLITE_OPEN_MEMORY : 0);
+
+  const database = bunSqlite.Database.open(config.filename, flags);
+  database.exec('PRAGMA foreign_keys = ON');
+
+  return {
+    close() {
+      database.close();
+    },
+    prepare(sql: string): KyselyCompatibleSqliteStatement {
+      const statement = database.prepare(sql);
+
+      return {
+        reader: statement.columnNames.length > 0,
+        all(parameters) {
+          return statement.all(Array.from(parameters));
+        },
+        run(parameters) {
+          return statement.run(Array.from(parameters));
+        },
+        iterate(parameters) {
+          return statement.iterate(Array.from(parameters));
+        },
+      };
+    },
+  };
+}
+
+function createNodeSqliteDatabase(
+  config: SqliteConnectionConfig,
+  nodeSqlite: NodeSqliteModule,
+): KyselyCompatibleSqliteDatabase {
+  const database = new nodeSqlite.DatabaseSync(config.filename, {
+    readOnly: config.readonly ?? false,
+  });
+
+  database.exec('PRAGMA foreign_keys = ON');
+
+  return {
+    close() {
+      database.close();
+    },
+    prepare(sql: string): KyselyCompatibleSqliteStatement {
+      const statement = database.prepare(sql);
+
+      return {
+        reader: statement.columns().length > 0,
+        all(parameters) {
+          return statement.all(...parameters);
+        },
+        run(parameters) {
+          return statement.run(...parameters);
+        },
+        iterate(parameters) {
+          return statement.iterate(...parameters);
+        },
+      };
+    },
+  };
+}
+
+async function createSqliteDatabase(
+  config: SqliteConnectionConfig,
+): Promise<KyselyCompatibleSqliteDatabase> {
+  if (isBunRuntime()) {
+    return createBunSqliteDatabase(config);
+  }
+
+  const nodeSqlite = await import(NODE_SQLITE_MODULE).catch(() => null);
+
+  if (nodeSqlite) {
+    return createNodeSqliteDatabase(config, nodeSqlite as NodeSqliteModule);
+  }
+
+  throw createUnsupportedSqliteRuntimeError();
+}
+
 export async function createDatabase(
  config: IdentityDBConnectionConfig,
 ): Promise<DatabaseConnection> {
  switch (config.client) {
    case 'sqlite': {
-      const sqlite = new Database(config.filename, {
-        readonly: config.readonly ?? false,
-      });
-
-      sqlite.pragma('foreign_keys = ON');
+      const sqlite = await createSqliteDatabase(config);

      const db = new Kysely<IdentityDatabaseSchema>({
        dialect: new SqliteDialect({
@@ -66,7 +232,6 @@ export async function createDatabase(
        db,
        destroy: async () => {
          await db.destroy();
-          sqlite.close();
        },
      };
    }
--- a/src/core/identity-db.ts
+++ b/src/core/identity-db.ts
@@ -1,39 +1,27 @@
 import {
+  type AddFactInput,
  type ConnectedTopic,
  type Fact,
  type FactTopic,
  type FindSimilarFactsInput,
  type IndexFactEmbeddingsInput,
+  type LinkTopicsInput,
  type ListTopicsOptions,
  type ScoredFact,
  type SearchFactsInput,
+  type Space,
+  type SpaceScopedInput,
  type Topic,
  type TopicLookupOptions,
  type TopicWithFacts,
+  type UpsertSpaceInput,
  type UpsertTopicInput,
-  type AddFactInput,
-  type LinkTopicsInput,
 } from '../types/api';
 import type { IngestStatementOptions } from '../ingestion/types';
 import type { DatabaseConnection, IdentityDBConnectionConfig } from '../adapters/dialect';
 import type { IdentityDatabaseSchema } from '../types/database';
-import type { FactRecord, TopicRecord } from '../types/domain';
+import type { FactRecord, SpaceRecord, TopicRecord } from '../types/domain';
 import { createDatabase } from '../adapters/dialect';
-import { IdentityDBError } from './errors';
-import { initializeSchema } from './migrations';
-import {
-  canonicalizeTopicName,
-  cosineSimilarity,
-  createContentHash,
-  createId,
-  deserializeEmbedding,
-  mapFactRow,
-  mapTopicRow,
-  normalizeTopicName,
-  nowIsoString,
-  serializeEmbedding,
-  serializeMetadata,
-} from './utils';
 import { extractFact } from '../ingestion/extractor';
 import {
  findFactRowsConnectingTopicIds,
@@ -41,16 +29,37 @@ import {
  findTopicLinksForFactIds,
 } from '../queries/facts';
 import {
+  type DatabaseExecutor,
+  findChildTopicRows,
  findConnectedTopicRows,
+  findParentTopicRows,
+  findSpaceRowByNormalizedName,
  findTopicRowByNameOrAlias,
  findTopicRowByNormalizedAlias,
  findTopicRowByNormalizedName,
  listTopicAliasRowsForTopicId,
  listTopicRows,
-  findChildTopicRows,
-  findParentTopicRows,
-  type DatabaseExecutor,
 } from '../queries/topics';
+import { IdentityDBError } from './errors';
+import { initializeSchema } from './migrations';
+import {
+  canonicalizeSpaceName,
+  canonicalizeTopicName,
+  cosineSimilarity,
+  createContentHash,
+  createId,
+  deserializeEmbedding,
+  mapFactRow,
+  mapSpaceRow,
+  mapTopicRow,
+  normalizeSpaceName,
+  normalizeTopicName,
+  nowIsoString,
+  serializeEmbedding,
+  serializeMetadata,
+} from './utils';
+
+const DEFAULT_SPACE_NAME = 'default';

 export class IdentityDB {
  private constructor(private readonly connection: DatabaseConnection) {}
@@ -68,6 +77,72 @@ export class IdentityDB {
    await this.connection.destroy();
  }

+  async upsertSpace(input: UpsertSpaceInput): Promise<Space> {
+    return this.connection.db.transaction().execute(async (trx) => {
+      const normalizedName = normalizeSpaceName(input.name);
+      if (normalizedName.length === 0) {
+        throw new IdentityDBError('Space name cannot be empty.');
+      }
+
+      const now = nowIsoString();
+      const existing = await findSpaceRowByNormalizedName(trx, normalizedName);
+
+      if (existing) {
+        await trx
+          .updateTable('spaces')
+          .set({
+            name: canonicalizeSpaceName(input.name),
+            description: input.description !== undefined ? input.description : existing.description,
+            metadata: input.metadata !== undefined ? serializeMetadata(input.metadata) : existing.metadata,
+            updated_at: now,
+          })
+          .where('id', '=', existing.id)
+          .execute();
+
+        const updated = await trx
+          .selectFrom('spaces')
+          .selectAll()
+          .where('id', '=', existing.id)
+          .executeTakeFirstOrThrow();
+
+        return mapSpaceRow(updated);
+      }
+
+      const createdRow: SpaceRecord = {
+        id: createId(),
+        name: canonicalizeSpaceName(input.name),
+        normalized_name: normalizedName,
+        description: input.description ?? null,
+        metadata: serializeMetadata(input.metadata),
+        created_at: now,
+        updated_at: now,
+      };
+
+      await trx.insertInto('spaces').values(createdRow).execute();
+      return mapSpaceRow(createdRow);
+    });
+  }
+
+  async getSpaceByName(name: string): Promise<Space | null> {
+    const normalizedName = normalizeSpaceName(name);
+    if (normalizedName.length === 0) {
+      return null;
+    }
+
+    const row = await findSpaceRowByNormalizedName(this.connection.db, normalizedName);
+    return row ? mapSpaceRow(row) : null;
+  }
+
+  async listSpaces(): Promise<Space[]> {
+    const rows = await this.connection.db
+      .selectFrom('spaces')
+      .selectAll()
+      .orderBy('normalized_name', 'asc')
+      .execute();
+
+    return rows.map(mapSpaceRow);
+  }
+
  async upsertTopic(input: UpsertTopicInput): Promise<Topic> {
    return this.upsertTopicInExecutor(this.connection.db, input);
  }
@@ -82,6 +157,7 @@ export class IdentityDB {
    }

    return this.connection.db.transaction().execute(async (trx) => {
+      const space = await this.getOrCreateSpaceInExecutor(trx, input.spaceName);
      const createdAt = nowIsoString();
      const factId = createId();

@@ -89,6 +165,7 @@ export class IdentityDB {
        .insertInto('facts')
        .values({
          id: factId,
+          space_id: space.id,
          statement: input.statement.trim(),
          summary: input.summary ?? null,
          source: input.source ?? null,
@@ -103,7 +180,11 @@ export class IdentityDB {

      for (let index = 0; index < input.topics.length; index += 1) {
        const topicInput = input.topics[index]!;
-        const topic = await this.upsertTopicInExecutor(trx, topicInput);
+        this.assertScopedTopicInput(space, topicInput.spaceName);
+        const topic = await this.upsertTopicInExecutor(trx, {
+          ...topicInput,
+          spaceName: space.name,
+        });

        await trx
          .insertInto('fact_topics')
@@ -125,6 +206,7 @@ export class IdentityDB {

      return {
        id: factId,
+        spaceId: space.id,
        statement: input.statement.trim(),
        summary: input.summary ?? null,
        source: input.source ?? null,
@@ -137,14 +219,12 @@ export class IdentityDB {
    });
  }

-  async ingestStatement(
-    statement: string,
-    options: IngestStatementOptions,
-  ): Promise<Fact> {
+  async ingestStatement(statement: string, options: IngestStatementOptions): Promise<Fact> {
    const extracted = await extractFact(statement, options.extractor);
    const factInput: AddFactInput = {
      statement: extracted.statement ?? statement,
      topics: extracted.topics,
+      spaceName: options.spaceName,
    };

    if (extracted.summary !== undefined) {
@@ -170,6 +250,7 @@ export class IdentityDB {
        topicNames: factInput.topics.map((topic) => topic.name),
        limit: 1,
        minimumScore: options.duplicateThreshold ?? 0.97,
+        spaceName: options.spaceName,
      });

      if (similarFacts[0]) {
@@ -180,15 +261,27 @@ export class IdentityDB {
    const fact = await this.addFact(factInput);

    if (options.embeddingProvider) {
-      await this.indexFactEmbedding(fact.id, { provider: options.embeddingProvider });
+      await this.indexFactEmbedding(fact.id, {
+        provider: options.embeddingProvider,
+        spaceName: options.spaceName,
+      });
    }

    return fact;
  }

  async indexFactEmbeddings(input: IndexFactEmbeddingsInput): Promise<void> {
-    const factRows = await this.connection.db.selectFrom('facts').selectAll().orderBy('created_at', 'asc').execute();
+    const space = await this.getSpaceForRead(input.spaceName);
+    if (input.spaceName && !space) {
+      return;
+    }

+    let factQuery = this.connection.db.selectFrom('facts').selectAll().orderBy('created_at', 'asc');
+    if (space) {
+      factQuery = factQuery.where('space_id', '=', space.id);
+    }
+
+    const factRows = await factQuery.execute();
    if (factRows.length === 0) {
      return;
    }
@@ -222,6 +315,13 @@ export class IdentityDB {
      throw new IdentityDBError(`Fact not found: ${factId}`);
    }

+    if (input.spaceName) {
+      const space = await this.getSpaceForRead(input.spaceName);
+      if (!space || space.id !== factRow.space_id) {
+        throw new IdentityDBError(`Fact ${factId} does not belong to space ${canonicalizeSpaceName(input.spaceName)}.`);
+      }
+    }
+
    const embedding = await input.provider.embed(factRow.statement);
    this.assertEmbeddingShape(embedding, input.provider.dimensions);

@@ -236,6 +336,11 @@ export class IdentityDB {
      return [];
    }

+    const space = await this.getSpaceForRead(input.spaceName);
+    if (input.spaceName && !space) {
+      return [];
+    }
+
    const queryEmbedding = await input.provider.embed(queryText);
    this.assertEmbeddingShape(queryEmbedding, input.provider.dimensions);

@@ -245,6 +350,7 @@ export class IdentityDB {
      topicNames: input.topicNames,
      limit: input.limit,
      minimumScore: input.minimumScore,
+      spaceId: space?.id,
    });
  }

@@ -254,6 +360,11 @@ export class IdentityDB {
      return [];
    }

+    const space = await this.getSpaceForRead(input.spaceName);
+    if (input.spaceName && !space) {
+      return [];
+    }
+
    const queryEmbedding = await input.provider.embed(statement);
    this.assertEmbeddingShape(queryEmbedding, input.provider.dimensions);

@@ -263,6 +374,7 @@ export class IdentityDB {
      topicNames: input.topicNames,
      limit: input.limit,
      minimumScore: input.minimumScore,
+      spaceId: space?.id,
    });
  }

@@ -279,12 +391,15 @@ export class IdentityDB {
    }

    await this.connection.db.transaction().execute(async (trx) => {
+      const space = await this.getOrCreateSpaceInExecutor(trx, input.spaceName);
      const parentTopic = await this.upsertTopicInExecutor(trx, {
        name: input.parentName,
        granularity: 'abstract',
+        spaceName: space.name,
      });
      const childTopic = await this.upsertTopicInExecutor(trx, {
        name: input.childName,
+        spaceName: space.name,
      });

      const existing = await trx
@@ -309,7 +424,7 @@ export class IdentityDB {
    });
  }

-  async addTopicAlias(canonicalName: string, alias: string): Promise<void> {
+  async addTopicAlias(canonicalName: string, alias: string, options?: SpaceScopedInput): Promise<void> {
    const normalizedAlias = normalizeTopicName(alias);

    if (normalizedAlias.length === 0) {
@@ -317,18 +432,22 @@ export class IdentityDB {
    }

    await this.connection.db.transaction().execute(async (trx) => {
-      const canonicalTopic = await this.upsertTopicInExecutor(trx, { name: canonicalName });
+      const space = await this.getOrCreateSpaceInExecutor(trx, options?.spaceName);
+      const canonicalTopic = await this.upsertTopicInExecutor(trx, {
+        name: canonicalName,
+        spaceName: space.name,
+      });

      if (normalizedAlias === canonicalTopic.normalizedName) {
        return;
      }

-      const exactTopicMatch = await findTopicRowByNormalizedName(trx, normalizedAlias);
+      const exactTopicMatch = await findTopicRowByNormalizedName(trx, space.id, normalizedAlias);
      if (exactTopicMatch && exactTopicMatch.id !== canonicalTopic.id) {
        throw new IdentityDBError('Cannot assign an alias that already belongs to another canonical topic.');
      }

-      const aliasMatch = await findTopicRowByNormalizedAlias(trx, normalizedAlias);
+      const aliasMatch = await findTopicRowByNormalizedAlias(trx, space.id, normalizedAlias);
      if (aliasMatch) {
        if (aliasMatch.id !== canonicalTopic.id) {
          throw new IdentityDBError('Cannot assign an alias that already resolves to another topic.');
@@ -341,6 +460,7 @@ export class IdentityDB {
        .insertInto('topic_aliases')
        .values({
          id: createId(),
+          space_id: space.id,
          topic_id: canonicalTopic.id,
          alias: canonicalizeTopicName(alias),
          normalized_alias: normalizedAlias,
@@ -352,47 +472,43 @@ export class IdentityDB {
    });
  }

-  async resolveTopic(name: string): Promise<Topic | null> {
-    const topicRow = await this.getRequiredTopicRow(name);
+  async resolveTopic(name: string, options?: SpaceScopedInput): Promise<Topic | null> {
+    const topicRow = await this.getRequiredTopicRow(name, options?.spaceName);
    return topicRow ? mapTopicRow(topicRow) : null;
  }

-  async getTopicAliases(name: string): Promise<string[]> {
-    const topicRow = await this.getRequiredTopicRow(name);
-
+  async getTopicAliases(name: string, options?: SpaceScopedInput): Promise<string[]> {
+    const topicRow = await this.getRequiredTopicRow(name, options?.spaceName);
    if (!topicRow) {
      return [];
    }

-    const aliasRows = await listTopicAliasRowsForTopicId(this.connection.db, topicRow.id);
+    const aliasRows = await listTopicAliasRowsForTopicId(this.connection.db, topicRow.space_id, topicRow.id);
    return aliasRows.map((aliasRow) => aliasRow.alias);
  }

-  async getTopicChildren(name: string): Promise<Topic[]> {
-    const topicRow = await this.getRequiredTopicRow(name);
-
+  async getTopicChildren(name: string, options?: SpaceScopedInput): Promise<Topic[]> {
+    const topicRow = await this.getRequiredTopicRow(name, options?.spaceName);
    if (!topicRow) {
      return [];
    }

-    const childRows = await findChildTopicRows(this.connection.db, topicRow.id);
+    const childRows = await findChildTopicRows(this.connection.db, topicRow.space_id, topicRow.id);
    return childRows.map(mapTopicRow);
  }

-  async getTopicParents(name: string): Promise<Topic[]> {
-    const topicRow = await this.getRequiredTopicRow(name);
-
+  async getTopicParents(name: string, options?: SpaceScopedInput): Promise<Topic[]> {
+    const topicRow = await this.getRequiredTopicRow(name, options?.spaceName);
    if (!topicRow) {
      return [];
    }

-    const parentRows = await findParentTopicRows(this.connection.db, topicRow.id);
+    const parentRows = await findParentTopicRows(this.connection.db, topicRow.space_id, topicRow.id);
    return parentRows.map(mapTopicRow);
  }

-  async getTopicLineage(name: string): Promise<Topic[]> {
-    const topicRow = await this.getRequiredTopicRow(name);
-
+  async getTopicLineage(name: string, options?: SpaceScopedInput): Promise<Topic[]> {
+    const topicRow = await this.getRequiredTopicRow(name, options?.spaceName);
    if (!topicRow) {
      return [];
    }
@@ -405,8 +521,7 @@ export class IdentityDB {
      const nextLevelIds: string[] = [];

      for (const currentId of currentLevelIds) {
-        const parentRows = await findParentTopicRows(this.connection.db, currentId);
-
+        const parentRows = await findParentTopicRows(this.connection.db, topicRow.space_id, currentId);
        for (const parentRow of parentRows) {
          if (visitedTopicIds.has(parentRow.id)) {
            continue;
@@ -424,97 +539,97 @@ export class IdentityDB {
    return lineage;
  }

-  async getTopicFacts(name: string): Promise<Fact[]> {
-    const topicRow = await this.getRequiredTopicRow(name);
-
+  async getTopicFacts(name: string, options?: SpaceScopedInput): Promise<Fact[]> {
+    const topicRow = await this.getRequiredTopicRow(name, options?.spaceName);
    if (!topicRow) {
      return [];
    }

-    const factRows = await findFactRowsForTopicId(this.connection.db, topicRow.id);
-    return this.hydrateFacts(factRows);
+    const factRows = await findFactRowsForTopicId(this.connection.db, topicRow.space_id, topicRow.id);
+    return this.hydrateFacts(factRows, topicRow.space_id);
  }

-  async getTopicFactsLinkedTo(name: string, linkedTopicName: string): Promise<Fact[]> {
-    return this.findFactsConnectingTopics([name, linkedTopicName]);
+  async getTopicFactsLinkedTo(name: string, linkedTopicName: string, options?: SpaceScopedInput): Promise<Fact[]> {
+    return this.findFactsConnectingTopics([name, linkedTopicName], options);
  }

-  async findFactsConnectingTopics(names: string[]): Promise<Fact[]> {
+  async findFactsConnectingTopics(names: string[], options?: SpaceScopedInput): Promise<Fact[]> {
    if (names.length === 0) {
      return [];
    }

-    const topicRows = await Promise.all(names.map((name) => this.getRequiredTopicRow(name)));
+    const space = await this.getSpaceForRead(options?.spaceName);
+    if (options?.spaceName && !space) {
+      return [];
+    }

+    const topicRows = await Promise.all(names.map((name) => this.getRequiredTopicRow(name, options?.spaceName)));
    if (topicRows.some((topicRow) => topicRow === undefined)) {
      return [];
    }

    const topicIds = topicRows.map((topicRow) => topicRow!.id);
-    const factRows = await findFactRowsConnectingTopicIds(this.connection.db, topicIds);
+    const spaceId = topicRows[0]!.space_id ?? space?.id;
+    const factRows = await findFactRowsConnectingTopicIds(this.connection.db, spaceId, topicIds);

-    return this.hydrateFacts(factRows);
+    return this.hydrateFacts(factRows, spaceId);
  }

-  async getTopicByName(
-    name: string,
-    options: { includeFacts: true },
-  ): Promise<TopicWithFacts | null>;
+  async getTopicByName(name: string, options: { includeFacts: true; spaceName?: string }): Promise<TopicWithFacts | null>;
  async getTopicByName(name: string, options?: TopicLookupOptions): Promise<Topic | null>;
-  async getTopicByName(
-    name: string,
-    options?: TopicLookupOptions,
-  ): Promise<Topic | TopicWithFacts | null> {
-    const topicRow = await this.getRequiredTopicRow(name);
-
+  async getTopicByName(name: string, options?: TopicLookupOptions): Promise<Topic | TopicWithFacts | null> {
+    const topicRow = await this.getRequiredTopicRow(name, options?.spaceName);
    if (!topicRow) {
      return null;
    }

    const topic = mapTopicRow(topicRow);
-
    if (options?.includeFacts) {
      return {
        ...topic,
-        facts: await this.getTopicFacts(name),
+        facts: await this.getTopicFacts(name, { spaceName: options.spaceName }),
      };
    }

    return topic;
  }

-  async listTopics(options: { includeFacts: true; limit?: number }): Promise<TopicWithFacts[]>;
+  async listTopics(options: { includeFacts: true; limit?: number; spaceName?: string }): Promise<TopicWithFacts[]>;
  async listTopics(options?: ListTopicsOptions): Promise<Topic[]>;
-  async listTopics(
-    options?: ListTopicsOptions,
-  ): Promise<Topic[] | TopicWithFacts[]> {
-    const rows = await listTopicRows(this.connection.db, options?.limit);
+  async listTopics(options?: ListTopicsOptions): Promise<Topic[] | TopicWithFacts[]> {
+    const space = await this.getSpaceForRead(options?.spaceName);
+    if (options?.spaceName && !space) {
+      return [];
+    }

+    const spaceId = space?.id ?? await this.getDefaultSpaceIdForRead();
+    if (!spaceId) {
+      return [];
+    }
+
+    const rows = await listTopicRows(this.connection.db, spaceId, options?.limit);
    if (!options?.includeFacts) {
      return rows.map(mapTopicRow);
    }

    const topicsWithFacts: TopicWithFacts[] = [];
-
    for (const row of rows) {
      topicsWithFacts.push({
        ...mapTopicRow(row),
-        facts: await this.getTopicFacts(row.name),
+        facts: await this.getTopicFacts(row.name, { spaceName: options?.spaceName }),
      });
    }

    return topicsWithFacts;
  }

-  async findConnectedTopics(name: string): Promise<ConnectedTopic[]> {
-    const topicRow = await this.getRequiredTopicRow(name);
-
+  async findConnectedTopics(name: string, options?: SpaceScopedInput): Promise<ConnectedTopic[]> {
+    const topicRow = await this.getRequiredTopicRow(name, options?.spaceName);
    if (!topicRow) {
      return [];
    }

-    const rows = await findConnectedTopicRows(this.connection.db, topicRow.id);
-
+    const rows = await findConnectedTopicRows(this.connection.db, topicRow.space_id, topicRow.id);
    return rows.map((row) => ({
      ...mapTopicRow(row),
      sharedFactCount: row.shared_fact_count,
@@ -527,18 +642,25 @@ export class IdentityDB {
    topicNames?: string[] | undefined;
    limit?: number | undefined;
    minimumScore?: number | undefined;
+    spaceId?: string | undefined;
  }): Promise<ScoredFact[]> {
-    const topicIds = await this.resolveTopicIds(input.topicNames);
+    const effectiveSpaceId = input.spaceId ?? await this.getDefaultSpaceIdForRead();
+    if (!effectiveSpaceId) {
+      return [];
+    }
+
+    const topicIds = await this.resolveTopicIds(input.topicNames, effectiveSpaceId);
    if (topicIds === null) {
      return [];
    }

    const factRows = topicIds.length > 0
-      ? await findFactRowsConnectingTopicIds(this.connection.db, topicIds)
+      ? await findFactRowsConnectingTopicIds(this.connection.db, effectiveSpaceId, topicIds)
      : await this.connection.db
          .selectFrom('facts')
          .innerJoin('fact_embeddings', 'fact_embeddings.fact_id', 'facts.id')
          .selectAll('facts')
+          .where('facts.space_id', '=', effectiveSpaceId)
          .where('fact_embeddings.model', '=', input.providerModel)
          .orderBy('facts.created_at', 'asc')
          .execute();
@@ -547,14 +669,14 @@ export class IdentityDB {
      return [];
    }

-    const embeddingRowsQuery = this.connection.db
+    const embeddingRows = await this.connection.db
      .selectFrom('fact_embeddings')
-      .selectAll()
-      .where('model', '=', input.providerModel);
-
-    const embeddingRows = factRows.length > 0
-      ? await embeddingRowsQuery.where('fact_id', 'in', factRows.map((factRow) => factRow.id)).execute()
-      : [];
+      .innerJoin('facts', 'facts.id', 'fact_embeddings.fact_id')
+      .selectAll('fact_embeddings')
+      .where('facts.space_id', '=', effectiveSpaceId)
+      .where('fact_embeddings.model', '=', input.providerModel)
+      .where('fact_embeddings.fact_id', 'in', factRows.map((factRow) => factRow.id))
+      .execute();

    const embeddingsByFactId = new Map(
      embeddingRows.map((embeddingRow) => [embeddingRow.fact_id, deserializeEmbedding(embeddingRow.embedding)]),
@@ -578,7 +700,7 @@ export class IdentityDB {
      return [];
    }

-    const hydratedFacts = await this.hydrateFacts(scoredRows.map((entry) => entry.factRow));
+    const hydratedFacts = await this.hydrateFacts(scoredRows.map((entry) => entry.factRow), effectiveSpaceId);
    const factsById = new Map(hydratedFacts.map((fact) => [fact.id, fact]));

    return scoredRows.map((entry) => ({
@@ -587,12 +709,12 @@ export class IdentityDB {
    }));
  }

-  private async resolveTopicIds(topicNames?: string[]): Promise<string[] | null> {
+  private async resolveTopicIds(topicNames: string[] | undefined, spaceId: string): Promise<string[] | null> {
    if (!topicNames || topicNames.length === 0) {
      return [];
    }

-    const topicRows = await Promise.all(topicNames.map((topicName) => this.getRequiredTopicRow(topicName)));
+    const topicRows = await Promise.all(topicNames.map((topicName) => this.getRequiredTopicRowInSpaceId(topicName, spaceId)));
    if (topicRows.some((topicRow) => !topicRow)) {
      return null;
    }
@@ -637,30 +759,28 @@ export class IdentityDB {
    }
  }

-  private async upsertTopicInExecutor(
-    executor: DatabaseExecutor,
-    input: UpsertTopicInput,
-  ): Promise<Topic> {
+  private async upsertTopicInExecutor(executor: DatabaseExecutor, input: UpsertTopicInput): Promise<Topic> {
    const normalizedName = normalizeTopicName(input.name);
-
    if (normalizedName.length === 0) {
      throw new IdentityDBError('Topic name cannot be empty.');
    }

-    const existing = await findTopicRowByNormalizedName(executor, normalizedName);
+    const space = await this.getOrCreateSpaceInExecutor(executor, input.spaceName);
+    const existing = await findTopicRowByNormalizedName(executor, space.id, normalizedName);
    const now = nowIsoString();

    if (existing) {
      return this.updateTopicRowInExecutor(executor, existing, input, now, true);
    }

-    const aliasedTopic = await findTopicRowByNormalizedAlias(executor, normalizedName);
+    const aliasedTopic = await findTopicRowByNormalizedAlias(executor, space.id, normalizedName);
    if (aliasedTopic) {
      return this.updateTopicRowInExecutor(executor, aliasedTopic, input, now, false);
    }

    const createdRow: TopicRecord = {
      id: createId(),
+      space_id: space.id,
      name: canonicalizeTopicName(input.name),
      normalized_name: normalizedName,
      category: input.category ?? 'custom',
@@ -672,7 +792,6 @@ export class IdentityDB {
    };

    await executor.insertInto('topics').values(createdRow).execute();
-
    return mapTopicRow(createdRow);
  }

@@ -705,22 +824,39 @@ export class IdentityDB {
    return mapTopicRow(updated);
  }

-  private async getRequiredTopicRow(name: string): Promise<TopicRecord | undefined> {
-    const normalizedName = normalizeTopicName(name);
+  private async getRequiredTopicRow(name: string, spaceName?: string): Promise<TopicRecord | undefined> {
+    const space = await this.getSpaceForRead(spaceName);
+    if (spaceName && !space) {
+      return undefined;
+    }

+    const spaceId = space?.id ?? await this.getDefaultSpaceIdForRead();
+    if (!spaceId) {
+      return undefined;
+    }
+
+    return this.getRequiredTopicRowInSpaceId(name, spaceId);
+  }
+
+  private async getRequiredTopicRowInSpaceId(name: string, spaceId: string): Promise<TopicRecord | undefined> {
+    const normalizedName = normalizeTopicName(name);
    if (normalizedName.length === 0) {
      return undefined;
    }

-    return findTopicRowByNameOrAlias(this.connection.db, normalizedName);
+    return findTopicRowByNameOrAlias(this.connection.db, spaceId, normalizedName);
  }

-  private async hydrateFacts(factRows: FactRecord[]): Promise<Fact[]> {
+  private async hydrateFacts(factRows: FactRecord[], spaceId?: string): Promise<Fact[]> {
+    if (factRows.length === 0) {
+      return [];
+    }
+
+    const effectiveSpaceId = spaceId ?? factRows[0]!.space_id;
    const factIds = factRows.map((fact) => fact.id);
-    const topicLinks = await findTopicLinksForFactIds(this.connection.db, factIds);
+    const topicLinks = await findTopicLinksForFactIds(this.connection.db, effectiveSpaceId, factIds);

    const topicsByFactId = new Map<string, FactTopic[]>();
-
    for (const topicLink of topicLinks) {
      const topics = topicsByFactId.get(topicLink.fact_id) ?? [];
      topics.push({
@@ -733,4 +869,57 @@ export class IdentityDB {

    return factRows.map((factRow) => mapFactRow(factRow, topicsByFactId.get(factRow.id) ?? []));
  }
+
+  private async getOrCreateSpaceInExecutor(executor: DatabaseExecutor, requestedSpaceName?: string): Promise<SpaceRecord> {
+    const normalizedName = normalizeSpaceName(requestedSpaceName ?? DEFAULT_SPACE_NAME);
+    const canonicalName = canonicalizeSpaceName(requestedSpaceName ?? DEFAULT_SPACE_NAME);
+    const existing = await findSpaceRowByNormalizedName(executor, normalizedName);
+    if (existing) {
+      return existing;
+    }
+
+    const now = nowIsoString();
+    const createdRow: SpaceRecord = {
+      id: createId(),
+      name: canonicalName,
+      normalized_name: normalizedName,
+      description: null,
+      metadata: null,
+      created_at: now,
+      updated_at: now,
+    };
+
+    await executor.insertInto('spaces').values(createdRow).execute();
+    return createdRow;
+  }
+
+  private async getSpaceForRead(spaceName?: string): Promise<SpaceRecord | undefined> {
+    if (!spaceName) {
+      return undefined;
+    }
+
+    const normalizedName = normalizeSpaceName(spaceName);
+    if (normalizedName.length === 0) {
+      return undefined;
+    }
+
+    return findSpaceRowByNormalizedName(this.connection.db, normalizedName);
+  }
+
+  private async getDefaultSpaceIdForRead(): Promise<string | undefined> {
+    const defaultSpace = await findSpaceRowByNormalizedName(this.connection.db, normalizeSpaceName(DEFAULT_SPACE_NAME));
+    return defaultSpace?.id;
+  }
+
+  private assertScopedTopicInput(space: SpaceRecord, topicSpaceName?: string): void {
+    if (!topicSpaceName) {
+      return;
+    }
+
+    if (normalizeSpaceName(topicSpaceName) !== space.normalized_name) {
+      throw new IdentityDBError(
+        `Fact topics cannot point to a different space than the fact itself (${space.name}).`,
+      );
+    }
+  }
 }
--- a/src/core/migrations.ts
+++ b/src/core/migrations.ts
@@ -4,6 +4,7 @@ import {
  FACTS_TABLE,
  FACT_EMBEDDINGS_TABLE,
  FACT_TOPICS_TABLE,
+  SPACES_TABLE,
  TOPIC_ALIASES_TABLE,
  TOPIC_RELATIONS_TABLE,
  TOPICS_TABLE,
@@ -14,23 +15,42 @@ export async function initializeSchema(
  db: Kysely<IdentityDatabaseSchema>,
 ): Promise<void> {
  await db.schema
-    .createTable(TOPICS_TABLE)
+    .createTable(SPACES_TABLE)
    .ifNotExists()
    .addColumn('id', 'text', (column) => column.primaryKey())
    .addColumn('name', 'text', (column) => column.notNull())
    .addColumn('normalized_name', 'text', (column) => column.notNull().unique())
-    .addColumn('category', 'text', (column) => column.notNull())
-    .addColumn('granularity', 'text', (column) => column.notNull())
    .addColumn('description', 'text')
    .addColumn('metadata', 'text')
    .addColumn('created_at', 'text', (column) => column.notNull())
    .addColumn('updated_at', 'text', (column) => column.notNull())
    .execute();

+  await db.schema
+    .createTable(TOPICS_TABLE)
+    .ifNotExists()
+    .addColumn('id', 'text', (column) => column.primaryKey())
+    .addColumn('space_id', 'text', (column) =>
+      column.notNull().references(`${SPACES_TABLE}.id`).onDelete('cascade'),
+    )
+    .addColumn('name', 'text', (column) => column.notNull())
+    .addColumn('normalized_name', 'text', (column) => column.notNull())
+    .addColumn('category', 'text', (column) => column.notNull())
+    .addColumn('granularity', 'text', (column) => column.notNull())
+    .addColumn('description', 'text')
+    .addColumn('metadata', 'text')
+    .addColumn('created_at', 'text', (column) => column.notNull())
+    .addColumn('updated_at', 'text', (column) => column.notNull())
+    .addUniqueConstraint('topics_space_normalized_name_key', ['space_id', 'normalized_name'])
+    .execute();
+
  await db.schema
    .createTable(FACTS_TABLE)
    .ifNotExists()
    .addColumn('id', 'text', (column) => column.primaryKey())
+    .addColumn('space_id', 'text', (column) =>
+      column.notNull().references(`${SPACES_TABLE}.id`).onDelete('cascade'),
+    )
    .addColumn('statement', 'text', (column) => column.notNull())
    .addColumn('summary', 'text')
    .addColumn('source', 'text')
@@ -88,14 +108,32 @@ export async function initializeSchema(
    .createTable(TOPIC_ALIASES_TABLE)
    .ifNotExists()
    .addColumn('id', 'text', (column) => column.primaryKey())
+    .addColumn('space_id', 'text', (column) =>
+      column.notNull().references(`${SPACES_TABLE}.id`).onDelete('cascade'),
+    )
    .addColumn('topic_id', 'text', (column) =>
      column.notNull().references(`${TOPICS_TABLE}.id`).onDelete('cascade'),
    )
    .addColumn('alias', 'text', (column) => column.notNull())
-    .addColumn('normalized_alias', 'text', (column) => column.notNull().unique())
+    .addColumn('normalized_alias', 'text', (column) => column.notNull())
    .addColumn('is_primary', 'integer', (column) => column.notNull())
    .addColumn('created_at', 'text', (column) => column.notNull())
    .addColumn('updated_at', 'text', (column) => column.notNull())
+    .addUniqueConstraint('topic_aliases_space_normalized_alias_key', ['space_id', 'normalized_alias'])
+    .execute();
+
+  await db.schema
+    .createIndex('topics_space_id_idx')
+    .ifNotExists()
+    .on(TOPICS_TABLE)
+    .column('space_id')
+    .execute();
+
+  await db.schema
+    .createIndex('facts_space_id_idx')
+    .ifNotExists()
+    .on(FACTS_TABLE)
+    .column('space_id')
    .execute();

  await db.schema
@@ -133,6 +171,13 @@ export async function initializeSchema(
    .column('child_topic_id')
    .execute();

+  await db.schema
+    .createIndex('topic_aliases_space_id_idx')
+    .ifNotExists()
+    .on(TOPIC_ALIASES_TABLE)
+    .column('space_id')
+    .execute();
+
  await db.schema
    .createIndex('topic_aliases_topic_id_idx')
    .ifNotExists()
--- a/src/core/schema.ts
+++ b/src/core/schema.ts
@@ -1,3 +1,4 @@
+export const SPACES_TABLE = 'spaces';
 export const TOPICS_TABLE = 'topics';
 export const FACTS_TABLE = 'facts';
 export const FACT_TOPICS_TABLE = 'fact_topics';
@@ -5,8 +6,19 @@ export const TOPIC_RELATIONS_TABLE = 'topic_relations';
 export const TOPIC_ALIASES_TABLE = 'topic_aliases';
 export const FACT_EMBEDDINGS_TABLE = 'fact_embeddings';

+export const SPACE_COLUMNS = [
+  'id',
+  'name',
+  'normalized_name',
+  'description',
+  'metadata',
+  'created_at',
+  'updated_at',
+] as const;
+
 export const TOPIC_COLUMNS = [
  'id',
+  'space_id',
  'name',
  'normalized_name',
  'category',
@@ -19,6 +31,7 @@ export const TOPIC_COLUMNS = [

 export const FACT_COLUMNS = [
  'id',
+  'space_id',
  'statement',
  'summary',
  'source',
@@ -45,6 +58,7 @@ export const TOPIC_RELATION_COLUMNS = [

 export const TOPIC_ALIAS_COLUMNS = [
  'id',
+  'space_id',
  'topic_id',
  'alias',
  'normalized_alias',
--- a/src/core/utils.ts
+++ b/src/core/utils.ts
@@ -1,7 +1,7 @@
 import { createHash, randomUUID } from 'node:crypto';

-import type { Fact, FactTopic, Topic } from '../types/api';
-import type { FactRecord, TopicRecord } from '../types/domain';
+import type { Fact, FactTopic, Space, Topic } from '../types/api';
+import type { FactRecord, SpaceRecord, TopicRecord } from '../types/domain';

 export function normalizeTopicName(name: string): string {
  return name.trim().replace(/\s+/g, ' ').toLowerCase();
@@ -11,6 +11,14 @@ export function canonicalizeTopicName(name: string): string {
  return name.trim().replace(/\s+/g, ' ');
 }

+export function normalizeSpaceName(name: string): string {
+  return normalizeTopicName(name);
+}
+
+export function canonicalizeSpaceName(name: string): string {
+  return canonicalizeTopicName(name);
+}
+
 export function nowIsoString(): string {
  return new Date().toISOString();
 }
@@ -71,9 +79,22 @@ export function cosineSimilarity(left: number[], right: number[]): number {
  return dot / (Math.sqrt(leftMagnitude) * Math.sqrt(rightMagnitude));
 }

+export function mapSpaceRow(record: SpaceRecord): Space {
+  return {
+    id: record.id,
+    name: record.name,
+    normalizedName: record.normalized_name,
+    description: record.description,
+    metadata: deserializeMetadata(record.metadata) as Space['metadata'],
+    createdAt: record.created_at,
+    updatedAt: record.updated_at,
+  };
+}
+
 export function mapTopicRow(record: TopicRecord): Topic {
  return {
    id: record.id,
+    spaceId: record.space_id,
    name: record.name,
    normalizedName: record.normalized_name,
    category: record.category,
@@ -88,6 +109,7 @@ export function mapTopicRow(record: TopicRecord): Topic {
 export function mapFactRow(record: FactRecord, topics: FactTopic[]): Fact {
  return {
    id: record.id,
+    spaceId: record.space_id,
    statement: record.statement,
    summary: record.summary,
    source: record.source,
--- a/src/ingestion/types.ts
+++ b/src/ingestion/types.ts
@@ -31,4 +31,5 @@ export interface IngestStatementOptions {
  extractor: FactExtractor;
  embeddingProvider?: EmbeddingProvider;
  duplicateThreshold?: number;
+  spaceName?: string;
 }
--- a/src/queries/facts.ts
+++ b/src/queries/facts.ts
@@ -13,12 +13,14 @@ export interface FactTopicJoinRow extends TopicRecord {

 export async function findFactRowsForTopicId(
  executor: DatabaseExecutor,
+  spaceId: string,
  topicId: string,
 ): Promise<FactRecord[]> {
  return executor
    .selectFrom('facts')
    .innerJoin('fact_topics', 'fact_topics.fact_id', 'facts.id')
    .selectAll('facts')
+    .where('facts.space_id', '=', spaceId)
    .where('fact_topics.topic_id', '=', topicId)
    .orderBy('facts.created_at', 'asc')
    .execute();
@@ -26,6 +28,7 @@ export async function findFactRowsForTopicId(

 export async function findFactRowsConnectingTopicIds(
  executor: DatabaseExecutor,
+  spaceId: string,
  topicIds: string[],
 ): Promise<FactRecord[]> {
  if (topicIds.length === 0) {
@@ -36,6 +39,7 @@ export async function findFactRowsConnectingTopicIds(
    .selectFrom('facts')
    .innerJoin('fact_topics', 'fact_topics.fact_id', 'facts.id')
    .selectAll('facts')
+    .where('facts.space_id', '=', spaceId)
    .where('fact_topics.topic_id', 'in', topicIds)
    .groupBy('facts.id')
    .having((eb) => eb.fn.count<number>('fact_topics.topic_id'), '=', topicIds.length)
@@ -45,6 +49,7 @@ export async function findFactRowsConnectingTopicIds(

 export async function findTopicLinksForFactIds(
  executor: DatabaseExecutor,
+  spaceId: string,
  factIds: string[],
 ): Promise<FactTopicJoinRow[]> {
  if (factIds.length === 0) {
@@ -60,6 +65,7 @@ export async function findTopicLinksForFactIds(
      'fact_topics.role as role',
      'fact_topics.position as position',
    ])
+    .where('topics.space_id', '=', spaceId)
    .where('fact_topics.fact_id', 'in', factIds)
    .orderBy('fact_topics.position', 'asc')
    .execute() as Promise<FactTopicJoinRow[]>;
--- a/src/queries/topics.ts
+++ b/src/queries/topics.ts
@@ -1,7 +1,7 @@
 import type { Kysely, Transaction } from 'kysely';

 import type { IdentityDatabaseSchema } from '../types/database';
-import type { TopicAliasRecord, TopicRecord } from '../types/domain';
+import type { SpaceRecord, TopicAliasRecord, TopicRecord } from '../types/domain';

 export type DatabaseExecutor = Kysely<IdentityDatabaseSchema> | Transaction<IdentityDatabaseSchema>;

@@ -9,48 +9,66 @@ export interface ConnectedTopicRow extends TopicRecord {
  shared_fact_count: number;
 }

+export async function findSpaceRowByNormalizedName(
+  executor: DatabaseExecutor,
+  normalizedName: string,
+): Promise<SpaceRecord | undefined> {
+  return executor
+    .selectFrom('spaces')
+    .selectAll()
+    .where('normalized_name', '=', normalizedName)
+    .executeTakeFirst();
+}
+
 export async function findTopicRowByNormalizedName(
  executor: DatabaseExecutor,
+  spaceId: string,
  normalizedName: string,
 ): Promise<TopicRecord | undefined> {
  return executor
    .selectFrom('topics')
    .selectAll()
+    .where('space_id', '=', spaceId)
    .where('normalized_name', '=', normalizedName)
    .executeTakeFirst();
 }

 export async function findTopicRowByNormalizedAlias(
  executor: DatabaseExecutor,
+  spaceId: string,
  normalizedAlias: string,
 ): Promise<TopicRecord | undefined> {
  return executor
    .selectFrom('topic_aliases')
    .innerJoin('topics', 'topics.id', 'topic_aliases.topic_id')
    .selectAll('topics')
+    .where('topic_aliases.space_id', '=', spaceId)
    .where('topic_aliases.normalized_alias', '=', normalizedAlias)
    .executeTakeFirst();
 }

 export async function findTopicRowByNameOrAlias(
  executor: DatabaseExecutor,
+  spaceId: string,
  normalizedName: string,
 ): Promise<TopicRecord | undefined> {
-  const directMatch = await findTopicRowByNormalizedName(executor, normalizedName);
+  const directMatch = await findTopicRowByNormalizedName(executor, spaceId, normalizedName);
  if (directMatch) {
    return directMatch;
  }

-  return findTopicRowByNormalizedAlias(executor, normalizedName);
+  return findTopicRowByNormalizedAlias(executor, spaceId, normalizedName);
 }

 export async function listTopicAliasRowsForTopicId(
  executor: DatabaseExecutor,
+  spaceId: string,
  topicId: string,
 ): Promise<TopicAliasRecord[]> {
  return executor
    .selectFrom('topic_aliases')
    .selectAll()
+    .where('space_id', '=', spaceId)
    .where('topic_id', '=', topicId)
    .orderBy('is_primary', 'desc')
    .orderBy('normalized_alias', 'asc')
@@ -59,9 +77,14 @@ export async function listTopicAliasRowsForTopicId(

 export async function listTopicRows(
  executor: DatabaseExecutor,
+  spaceId: string,
  limit?: number,
 ): Promise<TopicRecord[]> {
-  let query = executor.selectFrom('topics').selectAll().orderBy('normalized_name', 'asc');
+  let query = executor
+    .selectFrom('topics')
+    .selectAll()
+    .where('space_id', '=', spaceId)
+    .orderBy('normalized_name', 'asc');

  if (limit !== undefined) {
    query = query.limit(limit);
@@ -72,14 +95,18 @@ export async function listTopicRows(

 export async function findConnectedTopicRows(
  executor: DatabaseExecutor,
+  spaceId: string,
  topicId: string,
 ): Promise<ConnectedTopicRow[]> {
  return executor
    .selectFrom('fact_topics as source_link')
+    .innerJoin('facts', 'facts.id', 'source_link.fact_id')
    .innerJoin('fact_topics as related_link', 'related_link.fact_id', 'source_link.fact_id')
    .innerJoin('topics', 'topics.id', 'related_link.topic_id')
    .selectAll('topics')
    .select((eb) => eb.fn.count<number>('related_link.fact_id').as('shared_fact_count'))
+    .where('facts.space_id', '=', spaceId)
+    .where('topics.space_id', '=', spaceId)
    .where('source_link.topic_id', '=', topicId)
    .whereRef('related_link.topic_id', '!=', 'source_link.topic_id')
    .groupBy('topics.id')
@@ -90,12 +117,14 @@ export async function findConnectedTopicRows(

 export async function findChildTopicRows(
  executor: DatabaseExecutor,
+  spaceId: string,
  parentTopicId: string,
 ): Promise<TopicRecord[]> {
  return executor
    .selectFrom('topic_relations')
    .innerJoin('topics', 'topics.id', 'topic_relations.child_topic_id')
    .selectAll('topics')
+    .where('topics.space_id', '=', spaceId)
    .where('topic_relations.parent_topic_id', '=', parentTopicId)
    .where('topic_relations.relation', '=', 'parent_of')
    .orderBy('topics.normalized_name', 'asc')
@@ -104,12 +133,14 @@ export async function findChildTopicRows(

 export async function findParentTopicRows(
  executor: DatabaseExecutor,
+  spaceId: string,
  childTopicId: string,
 ): Promise<TopicRecord[]> {
  return executor
    .selectFrom('topic_relations')
    .innerJoin('topics', 'topics.id', 'topic_relations.parent_topic_id')
    .selectAll('topics')
+    .where('topics.space_id', '=', spaceId)
    .where('topic_relations.child_topic_id', '=', childTopicId)
    .where('topic_relations.relation', '=', 'parent_of')
    .orderBy('topics.normalized_name', 'asc')
--- a/src/types/api.ts
+++ b/src/types/api.ts
@@ -1,6 +1,26 @@
 import type { JsonValue, TopicCategory, TopicGranularity } from './domain';

-export interface UpsertTopicInput {
+export interface SpaceScopedInput {
+  spaceName?: string | undefined;
+}
+
+export interface UpsertSpaceInput {
+  name: string;
+  description?: string | null;
+  metadata?: JsonValue | null;
+}
+
+export interface Space {
+  id: string;
+  name: string;
+  normalizedName: string;
+  description: string | null;
+  metadata: JsonValue | null;
+  createdAt: string;
+  updatedAt: string;
+}
+
+export interface UpsertTopicInput extends SpaceScopedInput {
  name: string;
  category?: TopicCategory;
  granularity?: TopicGranularity;
@@ -12,7 +32,7 @@ export interface TopicLinkInput extends UpsertTopicInput {
  role?: string | null;
 }

-export interface AddFactInput {
+export interface AddFactInput extends SpaceScopedInput {
  statement: string;
  summary?: string | null;
  source?: string | null;
@@ -21,13 +41,14 @@ export interface AddFactInput {
  topics: TopicLinkInput[];
 }

-export interface LinkTopicsInput {
+export interface LinkTopicsInput extends SpaceScopedInput {
  parentName: string;
  childName: string;
 }

 export interface Topic {
  id: string;
+  spaceId: string;
  name: string;
  normalizedName: string;
  category: TopicCategory;
@@ -45,6 +66,7 @@ export interface FactTopic extends Topic {

 export interface Fact {
  id: string;
+  spaceId: string;
  statement: string;
  summary: string | null;
  source: string | null;
@@ -63,11 +85,11 @@ export interface ConnectedTopic extends Topic {
  sharedFactCount: number;
 }

-export interface TopicLookupOptions {
+export interface TopicLookupOptions extends SpaceScopedInput {
  includeFacts?: boolean;
 }

-export interface ListTopicsOptions {
+export interface ListTopicsOptions extends SpaceScopedInput {
  includeFacts?: boolean;
  limit?: number;
 }
@@ -79,11 +101,11 @@ export interface EmbeddingProvider {
  embedMany?(inputs: string[]): Promise<number[][]>;
 }

-export interface IndexFactEmbeddingsInput {
+export interface IndexFactEmbeddingsInput extends SpaceScopedInput {
  provider: EmbeddingProvider;
 }

-export interface SearchFactsInput {
+export interface SearchFactsInput extends SpaceScopedInput {
  query: string;
  provider: EmbeddingProvider;
  topicNames?: string[];
@@ -91,7 +113,7 @@ export interface SearchFactsInput {
  minimumScore?: number;
 }

-export interface FindSimilarFactsInput {
+export interface FindSimilarFactsInput extends SpaceScopedInput {
  statement: string;
  provider: EmbeddingProvider;
  topicNames?: string[];
--- a/src/types/database.ts
+++ b/src/types/database.ts
@@ -2,12 +2,14 @@ import type {
  FactEmbeddingRecord,
  FactRecord,
  FactTopicRecord,
+  SpaceRecord,
  TopicAliasRecord,
  TopicRecord,
  TopicRelationRecord,
 } from './domain';

 export interface IdentityDatabaseSchema {
+  spaces: SpaceRecord;
  topics: TopicRecord;
  facts: FactRecord;
  fact_topics: FactTopicRecord;
--- a/src/types/domain.ts
+++ b/src/types/domain.ts
@@ -5,8 +5,19 @@ export type TopicGranularity = 'abstract' | 'concrete' | 'mixed';
 export type JsonPrimitive = string | number | boolean | null;
 export type JsonValue = JsonPrimitive | JsonValue[] | { [key: string]: JsonValue };

+export interface SpaceRecord {
+  id: string;
+  name: string;
+  normalized_name: string;
+  description: string | null;
+  metadata: string | null;
+  created_at: string;
+  updated_at: string;
+}
+
 export interface TopicRecord {
  id: string;
+  space_id: string;
  name: string;
  normalized_name: string;
  category: TopicCategory;
@@ -19,6 +30,7 @@ export interface TopicRecord {

 export interface FactRecord {
  id: string;
+  space_id: string;
  statement: string;
  summary: string | null;
  source: string | null;
@@ -45,6 +57,7 @@ export interface TopicRelationRecord {

 export interface TopicAliasRecord {
  id: string;
+  space_id: string;
  topic_id: string;
  alias: string;
  normalized_alias: string;
--- a/tests/bun-runtime.test.ts
+++ b/tests/bun-runtime.test.ts
@@ -0,0 +1,43 @@
+import { execFile } from 'node:child_process';
+import { promisify } from 'node:util';
+
+import { describe, expect, it } from 'vitest';
+
+const execFileAsync = promisify(execFile);
+
+describe('Bun runtime compatibility', () => {
+  it('connects to sqlite from the package in Bun', async () => {
+    const script = [
+      "import { IdentityDB } from './src/index.ts';",
+      "const db = await IdentityDB.connect({ client: 'sqlite', filename: ':memory:' });",
+      'await db.initialize();',
+      "console.log('bun-sqlite-ok');",
+      'await db.close();',
+    ].join('\n');
+
+    const result = await execFileAsync('bun', ['--eval', script], {
+      cwd: process.cwd(),
+    });
+
+    expect(result.stdout).toContain('bun-sqlite-ok');
+  });
+
+  it('supports writes and reads through the Bun sqlite adapter path', async () => {
+    const script = [
+      "import { IdentityDB } from './src/index.ts';",
+      "const db = await IdentityDB.connect({ client: 'sqlite', filename: ':memory:' });",
+      'await db.initialize();',
+      "await db.addFact({ statement: 'Bun supports sqlite.', topics: [{ name: 'Bun', category: 'entity', granularity: 'concrete' }, { name: 'sqlite', category: 'concept', granularity: 'concrete' }] });",
+      "const facts = await db.getTopicFacts('Bun');",
+      "if (facts.length !== 1 || facts[0]?.statement !== 'Bun supports sqlite.') throw new Error('bun sqlite CRUD failed');",
+      "console.log('bun-sqlite-crud-ok');",
+      'await db.close();',
+    ].join('\n');
+
+    const result = await execFileAsync('bun', ['--eval', script], {
+      cwd: process.cwd(),
+    });
+
+    expect(result.stdout).toContain('bun-sqlite-crud-ok');
+  });
+});
--- a/tests/identity-db.test.ts
+++ b/tests/identity-db.test.ts
@@ -34,6 +34,58 @@ describe('IdentityDB topic and fact writes', () => {
    expect(topics).toHaveLength(1);
  });

+  it('keeps same normalized topic names isolated across spaces', async () => {
+    const alpha = await db.upsertTopic({
+      name: 'TypeScript',
+      category: 'entity',
+      granularity: 'concrete',
+      spaceName: 'A',
+    });
+
+    const beta = await db.upsertTopic({
+      name: 'TypeScript',
+      category: 'entity',
+      granularity: 'concrete',
+      spaceName: 'B',
+    });
+
+    expect(beta.id).not.toBe(alpha.id);
+
+    const alphaTopics = await db.listTopics({ includeFacts: false, spaceName: 'A' });
+    const betaTopics = await db.listTopics({ includeFacts: false, spaceName: 'B' });
+    const defaultTopics = await db.listTopics({ includeFacts: false });
+
+    expect(alphaTopics.map((topic) => topic.name)).toEqual(['TypeScript']);
+    expect(betaTopics.map((topic) => topic.name)).toEqual(['TypeScript']);
+    expect(defaultTopics).toHaveLength(0);
+  });
+
+  it('keeps alias resolution scoped to the requested space', async () => {
+    await db.upsertTopic({
+      name: 'TypeScript',
+      category: 'entity',
+      granularity: 'concrete',
+      spaceName: 'A',
+    });
+    await db.upsertTopic({
+      name: 'TeamSpeak',
+      category: 'entity',
+      granularity: 'concrete',
+      spaceName: 'B',
+    });
+
+    await db.addTopicAlias('TypeScript', 'TS', { spaceName: 'A' });
+    await db.addTopicAlias('TeamSpeak', 'TS', { spaceName: 'B' });
+
+    const alphaResolved = await db.resolveTopic('ts', { spaceName: 'A' });
+    const betaResolved = await db.resolveTopic('ts', { spaceName: 'B' });
+    const defaultResolved = await db.resolveTopic('ts');
+
+    expect(alphaResolved?.name).toBe('TypeScript');
+    expect(betaResolved?.name).toBe('TeamSpeak');
+    expect(defaultResolved).toBeNull();
+  });
+
  it('adds one fact that links multiple topics', async () => {
    const fact = await db.addFact({
      statement: 'I have worked with TypeScript since 2025.',
--- a/tests/migrations.test.ts
+++ b/tests/migrations.test.ts
@@ -16,7 +16,7 @@ afterEach(async () => {
 });

 describe('initializeSchema', () => {
-  it('creates the topics, facts, fact_embeddings, fact_topics, topic_relations, and topic_aliases tables', async () => {
+  it('creates the spaces, topics, facts, fact_embeddings, fact_topics, topic_relations, and topic_aliases tables', async () => {
    const connection = await createDatabase({ client: 'sqlite', filename: ':memory:' });
    openConnections.push(connection.destroy);

@@ -31,6 +31,7 @@ describe('initializeSchema', () => {

    const tableNames = tables.rows.map((row) => row.name);

+    expect(tableNames).toContain('spaces');
    expect(tableNames).toContain('topics');
    expect(tableNames).toContain('facts');
    expect(tableNames).toContain('fact_embeddings');
@@ -45,6 +46,7 @@ describe('initializeSchema', () => {

    await initializeSchema(connection.db);

+    const spaceColumns = await sql<{ name: string }>`PRAGMA table_info(spaces)`.execute(connection.db);
    const topicsColumns = await sql<{ name: string }>`PRAGMA table_info(topics)`.execute(connection.db);
    const factsColumns = await sql<{ name: string }>`PRAGMA table_info(facts)`.execute(connection.db);
    const factEmbeddingsColumns = await sql<{ name: string }>`PRAGMA table_info(fact_embeddings)`.execute(connection.db);
@@ -52,8 +54,19 @@ describe('initializeSchema', () => {
    const topicRelationsColumns = await sql<{ name: string }>`PRAGMA table_info(topic_relations)`.execute(connection.db);
    const topicAliasesColumns = await sql<{ name: string }>`PRAGMA table_info(topic_aliases)`.execute(connection.db);

+    expect(spaceColumns.rows.map((row) => row.name)).toEqual([
+      'id',
+      'name',
+      'normalized_name',
+      'description',
+      'metadata',
+      'created_at',
+      'updated_at',
+    ]);
+
    expect(topicsColumns.rows.map((row) => row.name)).toEqual([
      'id',
+      'space_id',
      'name',
      'normalized_name',
      'category',
@@ -66,6 +79,7 @@ describe('initializeSchema', () => {

    expect(factsColumns.rows.map((row) => row.name)).toEqual([
      'id',
+      'space_id',
      'statement',
      'summary',
      'source',
@@ -102,6 +116,7 @@ describe('initializeSchema', () => {

    expect(topicAliasesColumns.rows.map((row) => row.name)).toEqual([
      'id',
+      'space_id',
      'topic_id',
      'alias',
      'normalized_alias',
--- a/tests/queries.test.ts
+++ b/tests/queries.test.ts
@@ -2,9 +2,10 @@ import { afterEach, beforeEach, describe, expect, it } from 'vitest';

 import { IdentityDB } from '../src/core/identity-db';

-async function seedMemoryGraph(db: IdentityDB): Promise<void> {
+async function seedMemoryGraph(db: IdentityDB, spaceName?: string): Promise<void> {
  await db.addFact({
    statement: 'I have worked with TypeScript since 2025.',
+    spaceName,
    topics: [
      { name: 'I', category: 'entity', granularity: 'concrete', role: 'subject' },
      { name: 'TypeScript', category: 'entity', granularity: 'concrete', role: 'object' },
@@ -14,6 +15,7 @@ async function seedMemoryGraph(db: IdentityDB): Promise<void> {

  await db.addFact({
    statement: 'TypeScript is a programming language.',
+    spaceName,
    topics: [
      { name: 'TypeScript', category: 'entity', granularity: 'concrete', role: 'subject' },
      { name: 'programming language', category: 'concept', granularity: 'abstract', role: 'classification' },
@@ -23,11 +25,13 @@ async function seedMemoryGraph(db: IdentityDB): Promise<void> {
  await db.linkTopics({
    parentName: 'software technology',
    childName: 'programming language',
+    spaceName,
  });

  await db.linkTopics({
    parentName: 'programming language',
    childName: 'TypeScript',
+    spaceName,
  });
 }

@@ -114,6 +118,56 @@ describe('IdentityDB queries', () => {
    ]);
  });

+  it('keeps hierarchy and fact queries isolated per space', async () => {
+    const isolatedDb = await IdentityDB.connect({ client: 'sqlite', filename: ':memory:' });
+    try {
+      await isolatedDb.initialize();
+      await seedMemoryGraph(isolatedDb, 'A');
+
+      await isolatedDb.addFact({
+        statement: 'TypeScript is a typed superset.',
+        spaceName: 'B',
+        topics: [
+          { name: 'TypeScript', category: 'entity', granularity: 'concrete', role: 'subject' },
+          { name: 'superset', category: 'concept', granularity: 'abstract', role: 'classification' },
+        ],
+      });
+
+      await isolatedDb.linkTopics({
+        parentName: 'language family',
+        childName: 'TypeScript',
+        spaceName: 'B',
+      });
+
+      const alphaTopic = await isolatedDb.getTopicByName('TypeScript', {
+        includeFacts: true,
+        spaceName: 'A',
+      });
+      const betaTopic = await isolatedDb.getTopicByName('TypeScript', {
+        includeFacts: true,
+        spaceName: 'B',
+      });
+      const alphaParents = await isolatedDb.getTopicParents('TypeScript', { spaceName: 'A' });
+      const betaParents = await isolatedDb.getTopicParents('TypeScript', { spaceName: 'B' });
+      const alphaConnected = await isolatedDb.findConnectedTopics('TypeScript', { spaceName: 'A' });
+      const betaConnected = await isolatedDb.findConnectedTopics('TypeScript', { spaceName: 'B' });
+
+      expect(alphaTopic?.facts.map((fact) => fact.statement)).toEqual([
+        'I have worked with TypeScript since 2025.',
+        'TypeScript is a programming language.',
+      ]);
+      expect(betaTopic?.facts.map((fact) => fact.statement)).toEqual([
+        'TypeScript is a typed superset.',
+      ]);
+      expect(alphaParents.map((topic) => topic.name)).toEqual(['programming language']);
+      expect(betaParents.map((topic) => topic.name)).toEqual(['language family']);
+      expect(alphaConnected.map((topic) => topic.name)).toEqual(['2025', 'I', 'programming language']);
+      expect(betaConnected.map((topic) => topic.name)).toEqual(['superset']);
+    } finally {
+      await isolatedDb.close();
+    }
+  });
+
  it('resolves alias names in topic lookups', async () => {
    await db.addTopicAlias('TypeScript', 'TS');

--- a/tests/semantic-search.test.ts
+++ b/tests/semantic-search.test.ts
@@ -120,6 +120,53 @@ describe('IdentityDB semantic search', () => {
    expect(matches[0]?.statement).toBe('Bun runs TypeScript tooling quickly.');
    expect(matches[0]!.score).toBeGreaterThan(matches[1]!.score);
  });
+
+  it('keeps semantic search isolated per space', async () => {
+    const isolatedDb = await IdentityDB.connect({ client: 'sqlite', filename: ':memory:' });
+    try {
+      await isolatedDb.initialize();
+
+      await isolatedDb.addFact({
+        statement: 'Bun runs TypeScript tooling quickly.',
+        spaceName: 'A',
+        topics: [
+          { name: 'Bun', category: 'entity', granularity: 'concrete' },
+          { name: 'TypeScript', category: 'entity', granularity: 'concrete' },
+        ],
+      });
+
+      await isolatedDb.addFact({
+        statement: 'TypeScript runtime tooling belongs to another tenant.',
+        spaceName: 'B',
+        topics: [
+          { name: 'TypeScript', category: 'entity', granularity: 'concrete' },
+        ],
+      });
+
+      await isolatedDb.indexFactEmbeddings({ provider, spaceName: 'A' });
+      await isolatedDb.indexFactEmbeddings({ provider, spaceName: 'B' });
+
+      const alphaMatches = await isolatedDb.searchFacts({
+        query: 'TypeScript runtime tooling',
+        provider,
+        spaceName: 'A',
+      });
+      const betaMatches = await isolatedDb.searchFacts({
+        query: 'TypeScript runtime tooling',
+        provider,
+        spaceName: 'B',
+      });
+
+      expect(alphaMatches.map((match) => match.statement)).toEqual([
+        'Bun runs TypeScript tooling quickly.',
+      ]);
+      expect(betaMatches.map((match) => match.statement)).toEqual([
+        'TypeScript runtime tooling belongs to another tenant.',
+      ]);
+    } finally {
+      await isolatedDb.close();
+    }
+  });
 });

 describe('IdentityDB dedup-aware ingestion', () => {
@@ -167,4 +214,26 @@ describe('IdentityDB dedup-aware ingestion', () => {
    expect(facts).toHaveLength(1);
    expect(facts[0]?.statement).toBe('Bun runs TypeScript tooling quickly.');
  });
+
+  it('does not reuse a semantic duplicate from another space', async () => {
+    const first = await db.ingestStatement('Bun runs TypeScript tooling quickly.', {
+      extractor,
+      embeddingProvider: provider,
+      spaceName: 'A',
+    });
+
+    const second = await db.ingestStatement('Bun makes TypeScript tooling fast.', {
+      extractor,
+      embeddingProvider: provider,
+      duplicateThreshold: 0.95,
+      spaceName: 'B',
+    });
+
+    const alphaFacts = await db.getTopicFacts('TypeScript', { spaceName: 'A' });
+    const betaFacts = await db.getTopicFacts('TypeScript', { spaceName: 'B' });
+
+    expect(second.id).not.toBe(first.id);
+    expect(alphaFacts).toHaveLength(1);
+    expect(betaFacts).toHaveLength(1);
+  });
 });
Author	SHA1	Message	Date
Shinwoo PARK	6accd62df5	Replace better-sqlite3 with built-in SQLite drivers All checks were successful npm release / verify (push) Successful in 24s Details npm release / publish to npm (push) Successful in 11s Details	2026-05-12 16:52:22 +09:00
Shinwoo PARK	b77e8eea40	chore: release 0.2.0 All checks were successful npm release / verify (push) Successful in 13s Details npm release / publish to npm (push) Successful in 11s Details	2026-05-11 19:13:52 +09:00
Shinwoo PARK	cea45a552a	docs: document space isolation usage	2026-05-11 14:45:35 +09:00
Shinwoo PARK	d83fc31c59	feat: add isolated memory spaces	2026-05-11 14:45:28 +09:00
Shinwoo PARK	b908bc0bd9	docs: add IdentityDB space isolation plan	2026-05-11 14:28:08 +09:00