diff --git a/CHANGELOG.md b/CHANGELOG.md
index 1d9c01a..db1f969 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -10,6 +10,10 @@ Every entry says what changed as a caller sees it, why, and what to watch for 
 
 ### Added
 
+- **`performance/projects/snapshot/check.mjs`** checks the public read-only snapshot SDK with invented
+  data, preserving proposed state and alias provenance while omitting source bodies. It does not reset
+  or restore a project.
+
 - **`performance/projects/large-document/result-read-once.json`**: the same run on Memo 0.80.0 / Core 0.369.0 charges
   95,260 bytes, the document once (476,300 on 0.79.0). `after-fix.mjs` now pins those versions.
 
diff --git a/performance/projects/PROCESS.md b/performance/projects/PROCESS.md
index db64d29..36666ee 100644
--- a/performance/projects/PROCESS.md
+++ b/performance/projects/PROCESS.md
@@ -12,6 +12,10 @@ retained bytes; it does not run the applications or establish that a historical
 
 ## Existing evidence and its limits
 
+The [published snapshot check](snapshot/README.md) exercises a selected annotation read with invented
+data. It is functional release acceptance, separate from retrieval and extraction scores. It does
+not establish a complete project backup or a safe reset/restore path.
+
 The [installed post-fix observation](installed-observation/README.md) is a separate mutable-archive
 measurement. It publishes totals through an allowlisted projection; cases, source references and
 per-item rows remain private. Do not combine it with the frozen synthetic precision/recall scores.
diff --git a/performance/projects/README.md b/performance/projects/README.md
index d8ea10e..6ae3d29 100644
--- a/performance/projects/README.md
+++ b/performance/projects/README.md
@@ -1,5 +1,7 @@
 # Projects
 
+- [Published snapshots](snapshot/README.md): invented-data checks of the released read-only annotation SDK; selected scope, source-body omission and proposed-state preservation.
+
 - [Installed observation](installed-observation/README.md): allowlisted totals from a private fixed-window
   gathering rerun after the document pagination fix; finished pagination remains separate from archive
   completeness, relevance and interpretation.
diff --git a/performance/projects/snapshot/README.md b/performance/projects/snapshot/README.md
new file mode 100644
index 0000000..6f4f7fb
--- /dev/null
+++ b/performance/projects/snapshot/README.md
@@ -0,0 +1,43 @@
+# Published project annotation snapshot check
+
+Project gathering needs a safe way to retain selected annotations before an isolated reconstruction.
+This check asks whether the published SDK can read that selection without copying external source
+bodies, accepting proposed facts or creating an implicit store. It informs adoption of the read-only
+snapshot API; it does not establish that a project can be cleared or restored.
+
+## Setup and reproduction
+
+Linux x64, Node24.19.0, exact published `@wirecat/cli-core@0.373.0`. Install independently with
+lifecycle scripts disabled, then run the driver from this checkout:
+
+```sh
+T=$(mktemp -d -p /var/tmp) && HOME=$T XDG_CONFIG_HOME=$T/c XDG_DATA_HOME=$T/d XDG_CACHE_HOME=$T/k MESSAGING_STORE=$T/store WIRECAT_STATE_DIR=$T/s TMPDIR=$T NPM_CONFIG_USERCONFIG=/dev/null npm install --prefix "$T/package" --ignore-scripts --no-audit --no-fund @wirecat/cli-core@0.373.0 && HOME=$T XDG_CONFIG_HOME=$T/c XDG_DATA_HOME=$T/d XDG_CACHE_HOME=$T/k MESSAGING_STORE=$T/store WIRECAT_STATE_DIR=$T/s TMPDIR=$T node performance/projects/snapshot/check.mjs "$T/package/node_modules/@wirecat/cli-core/dist/store/index.js"
+```
+
+The driver seeds its own invented project, alias, imported document and agent-authored proposed
+statement through the package's public store API. It closes the writer before using the dedicated
+read-only snapshot API. It never accepts an existing input store or starts a provider connector.
+Its only argument selects the built package entry; it never reads the owner's archive or config.
+
+## Interpretation
+
+The retained result records assertions, not performance or semantic scores:
+
+- Version2 preserves alias provenance and project description.
+- Repeating the same snapshot returns the same fingerprint.
+- Proposed facts remain proposed, without confirmation provenance.
+- External document bodies and local source paths are absent from the snapshot.
+- Unknown fields are refused; a missing store is not created.
+- Importing the SDK and calling the explicit APIs do not create the implicit `MESSAGING_STORE` path.
+
+This selected format explicitly omits notes, specialized meeting memberships, tasks, memories,
+labels and findings. A document hash checks content equality, not its meaning. This check does not
+exercise destination preview, atomic restore, alias namespace collisions, OAuth, a live source,
+extraction quality or the version2 planner introduced after this snapshot release.
+
+The public fixture is independent of the private gathering request and any retained real-project
+references. [Result and release provenance](result.json) record all assertions passing against the published
+package. The registry tarball matches the release CI artifact byte-for-byte; its SHA-256 is
+`d7fcf5d3f355095e723bfd2d80cca0d3c6435a6d4ad6f69dfb0bd037cc07ada3`.
+The initial registry version lookups returned404 while npm propagated the upload; the check ran only
+after the version became visible and the downloaded bytes matched validation.
diff --git a/performance/projects/snapshot/check.mjs b/performance/projects/snapshot/check.mjs
new file mode 100644
index 0000000..dd254fe
--- /dev/null
+++ b/performance/projects/snapshot/check.mjs
@@ -0,0 +1,81 @@
+import assert from "node:assert/strict"
+import { existsSync, mkdtempSync } from "node:fs"
+import { tmpdir } from "node:os"
+import { join, resolve } from "node:path"
+import { pathToFileURL } from "node:url"
+
+// Run with temporary HOME/MESSAGING_STORE/WIRECAT_STATE_DIR; never accepts an existing store.
+const entry = process.argv[2]
+assert(entry, "pass the built published package store entry")
+assert(process.env.MESSAGING_STORE && process.env.HOME && process.env.WIRECAT_STATE_DIR)
+assert.equal(existsSync(process.env.MESSAGING_STORE), false)
+const sdk = await import(pathToFileURL(resolve(entry)).href)
+assert.equal(existsSync(process.env.MESSAGING_STORE), false)
+const dir = mkdtempSync(join(tmpdir(), "published-project-snapshot-"))
+const source = join(dir, "source.db")
+assert.equal(existsSync(source), false)
+const store = await sdk.openStore({ path: source, now: () => 1700000000000 })
+let project
+try {
+  project = await store.knowledge.addProject({
+    name: "Research Example",
+    key: "REX",
+    description: "Invented SDK check",
+  })
+  await store.knowledge.addVocabularyAlias({ kind: "project", id: project.id }, "Example study")
+  const folder = await store.notes.addFolder({ name: "Invented sources" })
+  const { note: doc } = await store.notes.saveFileNote({
+    folderId: folder.id,
+    path: "source.md",
+    title: "Example evidence",
+    text: "INVENTED_SOURCE_BODY_SENTINEL",
+  })
+  await store.facts.add({
+    type: "statement",
+    statement: "An invented report awaits review",
+    project: project.ref,
+    by: { bot: "synthetic-sdk-reviewer" },
+    evidence: [doc.ref],
+  })
+} finally {
+  await store.close()
+}
+const first = await sdk.snapshotProjectAnnotations({ source, project: project.ref })
+const second = await sdk.snapshotProjectAnnotations({ source, project: project.ref })
+assert.equal(first.snapshot.version, 2)
+assert.equal(first.snapshot.project.description, "Invented SDK check")
+assert.equal(first.snapshot.aliases[0].name, "Example study")
+assert.equal(first.snapshot.aliases[0].source, "owner")
+assert.equal(first.snapshot.facts.length, 1)
+assert.equal(first.snapshot.facts[0].status, "proposed")
+assert.equal(first.snapshot.facts[0].confirmed_by, null)
+assert.equal(first.fingerprint, second.fingerprint)
+assert.equal(first.snapshot.coverage.notes, "omitted")
+assert.equal(first.snapshot.coverage.meeting_memberships, "omitted")
+const json = JSON.stringify(first.snapshot)
+assert(!json.includes("INVENTED_SOURCE_BODY_SENTINEL"))
+assert(!json.includes(dir))
+assert.deepEqual(sdk.decodeProjectAnnotationSnapshot(json), first.snapshot)
+assert.equal(sdk.projectAnnotationSnapshotFingerprint(json), first.fingerprint)
+assert.throws(() => sdk.decodeProjectAnnotationSnapshot(JSON.stringify({ ...first.snapshot, unexpected: true })), {
+  code: "validation_error",
+})
+await assert.rejects(() => sdk.snapshotProjectAnnotations({ source: join(dir, "absent.db"), project: project.ref }), {
+  code: "not_found",
+})
+assert.equal(existsSync(join(dir, "absent.db")), false)
+assert.equal(existsSync(process.env.MESSAGING_STORE), false)
+process.stdout.write(
+  `${JSON.stringify({
+    public_sdk: true,
+    snapshot_version: 2,
+    stable_repeat: true,
+    proposed_state_preserved: true,
+    alias_provenance_preserved: true,
+    external_bodies_omitted: true,
+    unknown_field_refused: true,
+    missing_store_not_created: true,
+    implicit_store_created: false,
+    owner_data_used: false,
+  })}\n`,
+)
diff --git a/performance/projects/snapshot/result.json b/performance/projects/snapshot/result.json
new file mode 100644
index 0000000..63d1df2
--- /dev/null
+++ b/performance/projects/snapshot/result.json
@@ -0,0 +1,30 @@
+{
+  "purpose": "Published selected-annotation snapshot acceptance, not a retrieval or restore score",
+  "package": {
+    "name": "@wirecat/cli-core",
+    "version": "0.373.0",
+    "source_commit": "73d84265481aa3662f91337986b8194ef883646b",
+    "release_run": 39432002556,
+    "tarball_sha256": "d7fcf5d3f355095e723bfd2d80cca0d3c6435a6d4ad6f69dfb0bd037cc07ada3",
+    "integrity": "sha512-+2Hn6NgUYqMaL0dnrlnTx6ACtKIMBRZ36MlSK0WvDtKQjp1/C1HidMPCoukN6+mPD4XqshiDel+0DtqpWKm0QQ==",
+    "registry_matches_validated": true,
+    "entry_sha256": "929011e1be283c8b15d7b1fc627fb0c33d809a76710517cc65eb300e438b2e61"
+  },
+  "runtime": {
+    "node": "v24.19.0",
+    "platform": "linux",
+    "arch": "x64"
+  },
+  "checks": {
+    "public_sdk": true,
+    "snapshot_version": 2,
+    "stable_repeat": true,
+    "proposed_state_preserved": true,
+    "alias_provenance_preserved": true,
+    "external_bodies_omitted": true,
+    "unknown_field_refused": true,
+    "missing_store_not_created": true,
+    "implicit_store_created": false,
+    "owner_data_used": false
+  }
+}