diff --git a/packages/mcp-server/src/legacy-schema.test.ts b/packages/mcp-server/src/legacy-schema.test.ts
new file mode 100644
index 00000000..2730769e
--- /dev/null
+++ b/packages/mcp-server/src/legacy-schema.test.ts
@@ -0,0 +1,220 @@
+import assert from 'node:assert/strict'
+import fs from 'node:fs'
+import os from 'node:os'
+import path from 'node:path'
+import test from 'node:test'
+import { Client } from '@modelcontextprotocol/sdk/client/index.js'
+import { InMemoryTransport } from '@modelcontextprotocol/sdk/inMemory.js'
+import { McpServer } from '@modelcontextprotocol/sdk/server/mcp.js'
+import { CURRENT_SCHEMA_VERSION } from '@openchatlab/core'
+import { DatabaseManager, NodePathProvider, readDataDirCompatibilityMeta } from '@openchatlab/node-runtime'
+import { startMcpServer } from './server'
+import { openTestSqliteDatabase } from '../../../tests/helpers/sqlite.mts'
+
+test('real MCP tools and resources reject a released schema-v4 database until a writable upgrade', async (t) => {
+  const root = fs.mkdtempSync(path.join(os.tmpdir(), 'chatlab-mcp-v4-preflight-'))
+  t.after(() => fs.rmSync(root, { recursive: true, force: true }))
+  const dataDir = path.join(root, 'data')
+  const dbDir = path.join(dataDir, 'databases')
+  fs.mkdirSync(dbDir, { recursive: true })
+  const dbPath = path.join(dbDir, 'legacy-v4.db')
+
+  // Matches the published v4 member.name/nickname layout covered by
+  // database-manager.test.ts, rather than a new-schema fixture with a v4 tag.
+  const fixture = openTestSqliteDatabase(dbPath)
+  try {
+    fixture.exec(`
+      CREATE TABLE meta (
+        name TEXT NOT NULL, platform TEXT NOT NULL, type TEXT NOT NULL,
+        imported_at INTEGER NOT NULL, schema_version INTEGER DEFAULT 4
+      );
+      INSERT INTO meta (name, platform, type, imported_at, schema_version)
+      VALUES ('Old Chat', 'qq', 'group', 1000, 4);
+      CREATE TABLE member (
+        id INTEGER PRIMARY KEY AUTOINCREMENT,
+        platform_id TEXT NOT NULL UNIQUE, name TEXT NOT NULL, nickname TEXT
+      );
+      INSERT INTO member (platform_id, name, nickname)
+      VALUES ('u1', 'Alice Account', 'Alice Group');
+      CREATE TABLE message (
+        id INTEGER PRIMARY KEY AUTOINCREMENT,
+        sender_id INTEGER NOT NULL, ts INTEGER NOT NULL, type INTEGER NOT NULL, content TEXT
+      );
+      INSERT INTO message (sender_id, ts, type, content) VALUES (1, 1000, 0, 'hello');
+      CREATE TABLE chat_session (
+        id INTEGER PRIMARY KEY AUTOINCREMENT,
+        start_ts INTEGER NOT NULL, end_ts INTEGER NOT NULL,
+        message_count INTEGER DEFAULT 0, is_manual INTEGER DEFAULT 0, summary TEXT
+      );
+      CREATE TABLE message_context (
+        message_id INTEGER PRIMARY KEY, session_id INTEGER NOT NULL, topic_id INTEGER
+      );
+    `)
+  } finally {
+    fixture.close()
+  }
+
+  const beforeDb = fs.readFileSync(dbPath)
+  const markerPath = path.join(dataDir, '.chatlab-meta.json')
+  assert.equal(readDataDirCompatibilityMeta(dataDir), null)
+
+  const dbManager = new DatabaseManager(new NodePathProvider(dataDir), {
+    runtime: { version: '0.37.6', kind: 'mcp' },
+  })
+  t.after(() => dbManager.closeAll())
+
+  // The shared read-only API is also used by CLI auto-import analysis. It must
+  // continue to discover genuine v4 sessions without requiring MCP's v10 schema.
+  assert.deepEqual(dbManager.listSessionIdsReadonly(), ['legacy-v4'])
+  const sharedDb = dbManager.openReadonly('legacy-v4')
+  assert.ok(sharedDb)
+  assert.equal(sharedDb.readonly, true)
+  sharedDb.close()
+  assert.deepEqual(fs.readFileSync(dbPath), beforeDb)
+  assert.equal(fs.existsSync(markerPath), false)
+
+  const client = new Client({ name: 'legacy-schema-test-client', version: '1.0.0' })
+  const [clientTransport, serverTransport] = InMemoryTransport.createLinkedPair()
+  // Exercise the actual registration and resource callbacks, substituting only
+  // in-memory transport for stdio as in the protocol contract test above.
+  const connect = McpServer.prototype.connect
+  t.mock.method(McpServer.prototype, 'connect', function (this: McpServer) {
+    t.after(() => this.close())
+    return connect.call(this, serverTransport)
+  })
+  await startMcpServer({ version: '0.37.6', dbManager })
+  await client.connect(clientTransport)
+  try {
+    for (const [name, args] of [
+      ['chatlab_list_sessions', {}],
+      ['chatlab_get_session_info', { session_id: 'legacy-v4' }],
+      ['chatlab_get_recent_messages', { session_id: 'legacy-v4' }],
+      ['chatlab_execute_sql', { session_id: 'legacy-v4', sql: 'SELECT 1' }],
+    ] as const) {
+      const result = await client.callTool({ name, arguments: { ...args, format: 'json' } })
+      assert.equal(result.isError, true, `${name} should require a schema upgrade`)
+      assert.match(JSON.stringify(result.content), /schema v4.*schema v10.*migrate/i)
+    }
+    for (const uri of [
+      'chatlab://sessions',
+      'chatlab://sessions/legacy-v4/meta',
+      'chatlab://sessions/legacy-v4/schema',
+    ]) {
+      await assert.rejects(client.readResource({ uri }), /schema v4.*schema v10.*migrate/i, uri)
+    }
+    assert.deepEqual(fs.readFileSync(dbPath), beforeDb)
+    assert.equal(fs.existsSync(markerPath), false, 'MCP must not repair the compatibility marker')
+
+    // This explicit writable operation is intentionally outside MCP dispatch.
+    const migrated = dbManager.open('legacy-v4')
+    assert.ok(migrated)
+    assert.equal(
+      (migrated.prepare('SELECT schema_version FROM meta').get() as { schema_version: number }).schema_version,
+      CURRENT_SCHEMA_VERSION
+    )
+    dbManager.close('legacy-v4')
+    const afterUpgrade = fs.readFileSync(dbPath)
+    const repairedMarker = fs.readFileSync(markerPath)
+
+    const list = await client.callTool({ name: 'chatlab_list_sessions', arguments: { format: 'json' } })
+    assert.equal(list.isError, undefined, JSON.stringify(list.content))
+    assert.match(JSON.stringify(list.content), /Old Chat/)
+    const info = await client.callTool({
+      name: 'chatlab_get_session_info',
+      arguments: { session_id: 'legacy-v4', format: 'json' },
+    })
+    assert.equal(info.isError, undefined, JSON.stringify(info.content))
+
+    const listResource = await client.readResource({ uri: 'chatlab://sessions' })
+    assert.match(JSON.stringify(listResource.contents), /Old Chat/)
+    const metaResource = await client.readResource({ uri: 'chatlab://sessions/legacy-v4/meta' })
+    assert.match(JSON.stringify(metaResource.contents), /Old Chat/)
+    const schemaResource = await client.readResource({ uri: 'chatlab://sessions/legacy-v4/schema' })
+    assert.match(JSON.stringify(schemaResource.contents), /member/)
+    assert.deepEqual(fs.readFileSync(dbPath), afterUpgrade)
+    assert.deepEqual(fs.readFileSync(markerPath), repairedMarker)
+  } finally {
+    await client.close()
+  }
+})
+
+test('MCP tools and resources refuse invalid SQLite schema versions before SQL dispatch', async (t) => {
+  const root = fs.mkdtempSync(path.join(os.tmpdir(), 'chatlab-mcp-invalid-schema-'))
+  t.after(() => fs.rmSync(root, { recursive: true, force: true }))
+  const dataDir = path.join(root, 'data')
+  const dbDir = path.join(dataDir, 'databases')
+  fs.mkdirSync(dbDir, { recursive: true })
+  const dbPath = path.join(dbDir, 'invalid-version.db')
+  const fixture = openTestSqliteDatabase(dbPath)
+  try {
+    fixture.exec(`
+      CREATE TABLE meta (
+        name TEXT, platform TEXT, type TEXT, imported_at INTEGER, schema_version INTEGER
+      );
+      INSERT INTO meta VALUES ('Legacy', 'qq', 'group', 1000, 'not-a-version');
+      CREATE TABLE member (id INTEGER, platform_id TEXT, name TEXT, nickname TEXT);
+      INSERT INTO member VALUES (1, 'legacy-user', 'Alice', 'Alice Group');
+      CREATE TABLE message (id INTEGER, sender_id INTEGER, ts INTEGER, type INTEGER, content TEXT);
+      INSERT INTO message VALUES (1, 1, 1000, 0, 'legacy message');
+    `)
+    const actual = fixture.prepare('SELECT schema_version, typeof(schema_version) AS storage FROM meta').get() as {
+      schema_version: unknown
+      storage: string
+    }
+    assert.equal(actual.schema_version, 'not-a-version')
+    assert.equal(actual.storage, 'text')
+  } finally {
+    fixture.close()
+  }
+
+  const originalDb = fs.readFileSync(dbPath)
+  const markerPath = path.join(dataDir, '.chatlab-meta.json')
+  assert.equal(readDataDirCompatibilityMeta(dataDir), null)
+
+  const dbManager = new DatabaseManager(new NodePathProvider(dataDir), {
+    runtime: { version: '0.37.6', kind: 'mcp' },
+  })
+  t.after(() => dbManager.closeAll())
+  // CLI import analysis must retain read-only access to older/unrecognized
+  // schema candidates, without silently applying MCP's stricter rule.
+  assert.deepEqual(dbManager.listSessionIdsReadonly(), ['invalid-version'])
+  const sharedDb = dbManager.openReadonly('invalid-version')
+  assert.ok(sharedDb)
+  assert.equal(sharedDb.readonly, true)
+  sharedDb.close()
+
+  const client = new Client({ name: 'invalid-schema-test-client', version: '1.0.0' })
+  const [clientTransport, serverTransport] = InMemoryTransport.createLinkedPair()
+  const connect = McpServer.prototype.connect
+  t.mock.method(McpServer.prototype, 'connect', function (this: McpServer) {
+    t.after(() => this.close())
+    return connect.call(this, serverTransport)
+  })
+  await startMcpServer({ version: '0.37.6', dbManager })
+  await client.connect(clientTransport)
+  try {
+    for (const [name, args] of [
+      ['chatlab_list_sessions', {}],
+      ['chatlab_execute_sql', { session_id: 'invalid-version', sql: 'SELECT 1 AS ok' }],
+      ['chatlab_get_session_info', { session_id: 'invalid-version' }],
+      ['chatlab_get_schema', { session_id: 'invalid-version' }],
+    ] as const) {
+      const result = await client.callTool({ name, arguments: { ...args, format: 'json' } })
+      assert.equal(result.isError, true, `${name} incorrectly accepted an invalid schema version`)
+      assert.match(JSON.stringify(result.content), /invalid schema version/i, name)
+      assert.doesNotMatch(JSON.stringify(result.content), /no such column/i, name)
+    }
+
+    for (const uri of [
+      'chatlab://sessions',
+      'chatlab://sessions/invalid-version/meta',
+      'chatlab://sessions/invalid-version/schema',
+    ]) {
+      await assert.rejects(client.readResource({ uri }), /invalid schema version/i, uri)
+    }
+    assert.deepEqual(fs.readFileSync(dbPath), originalDb)
+    assert.equal(fs.existsSync(markerPath), false)
+  } finally {
+    await client.close()
+  }
+})
diff --git a/packages/mcp-server/src/server.test.ts b/packages/mcp-server/src/server.test.ts
index 13037a5e..7255312f 100644
--- a/packages/mcp-server/src/server.test.ts
+++ b/packages/mcp-server/src/server.test.ts
@@ -23,7 +23,7 @@ test('advertises every ChatLab MCP query tool as read-only', async () => {
   const [clientTransport, serverTransport] = InMemoryTransport.createLinkedPair()
 
   try {
-    registerTools(server, { listSessionIdsReadonly: () => [], openReadonly: () => null })
+    registerTools(server, { listSessionIdsMcpReadonly: () => [], openMcpReadonly: () => null })
     await server.connect(serverTransport)
     await client.connect(clientTransport)
 
@@ -49,7 +49,7 @@ test('advertises every ChatLab MCP query tool as read-only', async () => {
   }
 })
 
-test('MCP queries do not migrate a pending-schema session or raise the data compatibility gate', async (t) => {
+test('MCP rejects schema v5 before dispatch without migrating or raising the compatibility gate', async (t) => {
   const root = fs.mkdtempSync(path.join(os.tmpdir(), 'chatlab-mcp-readonly-'))
   t.after(() => fs.rmSync(root, { recursive: true, force: true }))
 
@@ -116,7 +116,8 @@ test('MCP queries do not migrate a pending-schema session or raise the data comp
       ['chatlab_execute_sql', { session_id: 'legacy', sql: 'SELECT content FROM message' }],
     ] as const) {
       const result = await client.callTool({ name, arguments: { ...args, format: 'json' } })
-      assert.equal(result.isError, undefined, `${name}: ${JSON.stringify(result.content)}`)
+      assert.equal(result.isError, true, `${name} should require an explicit upgrade`)
+      assert.match(JSON.stringify(result.content), /schema v5.*schema v10.*migrate/i)
       assert.equal(readDataDirCompatibilityMeta(dataDir), null, `${name} raised the compatibility gate`)
       assert.deepEqual(fs.readFileSync(dbPath), initialDatabase, `${name} modified the legacy database`)
     }
@@ -135,7 +136,7 @@ test('MCP queries do not migrate a pending-schema session or raise the data comp
   }
 })
 
-test('segment summaries handle v9 pending schema without migration and preserve v10 results', async (t) => {
+test('MCP requires an explicit v9 upgrade and preserves current v10 summary results', async (t) => {
   const root = fs.mkdtempSync(path.join(os.tmpdir(), 'chatlab-mcp-v9-summaries-'))
   t.after(() => fs.rmSync(root, { recursive: true, force: true }))
   const dataDir = path.join(root, 'data')
@@ -216,8 +217,8 @@ test('segment summaries handle v9 pending schema without migration and preserve
       name: 'chatlab_get_segment_summaries',
       arguments: { session_id: 'v9', format: 'json' },
     })
-    assert.equal(oldResult.isError, undefined, JSON.stringify(oldResult.content))
-    assert.match((oldResult.content as Array<{ text: string }>)[0].text, /No segments with summaries found/)
+    assert.equal(oldResult.isError, true, JSON.stringify(oldResult.content))
+    assert.match(JSON.stringify(oldResult.content), /schema v9.*schema v10.*migrate/i)
     assert.deepEqual(fs.readFileSync(legacyPath), beforeV9)
     assert.deepEqual(fs.readFileSync(path.join(dataDir, '.chatlab-meta.json')), beforeGate)
 
@@ -333,7 +334,8 @@ test('read-only MCP rejects schema v6 without a repaired compatibility gate', as
       name: 'chatlab_get_session_info',
       arguments: { session_id: 'v6', format: 'json' },
     })
-    assert.equal(result.isError, undefined, JSON.stringify(result.content))
+    assert.equal(result.isError, true, JSON.stringify(result.content))
+    assert.match(JSON.stringify(result.content), /schema v6.*schema v10.*migrate/i)
     assert.deepEqual(fs.readFileSync(dbPath), beforeDb)
     assert.deepEqual(fs.readFileSync(path.join(dataDir, '.chatlab-meta.json')), gateAfterRepair)
   } finally {
diff --git a/packages/mcp-server/src/server.ts b/packages/mcp-server/src/server.ts
index b4f43771..c1f46ad5 100644
--- a/packages/mcp-server/src/server.ts
+++ b/packages/mcp-server/src/server.ts
@@ -60,9 +60,9 @@ export function registerTools(server: McpServer, dbManager: McpDatabaseManager,
             const context: SessionListContext = {
               db: null as any,
               sessionId: '',
-              listSessionIds: () => dbManager.listSessionIdsReadonly(),
+              listSessionIds: () => dbManager.listSessionIdsMcpReadonly(),
               openDb: (id) => {
-                const db = dbManager.openReadonly(id)
+                const db = dbManager.openMcpReadonly(id)
                 if (db) openedDbs.push(db)
                 return db
               },
@@ -92,7 +92,7 @@ export function registerTools(server: McpServer, dbManager: McpDatabaseManager,
       async (params) => {
         const sessionId = params.session_id as string
         const format = params.format as string | undefined
-        const db = dbManager.openReadonly(sessionId)
+        const db = dbManager.openMcpReadonly(sessionId)
         if (!db) {
           return {
             content: [{ type: 'text' as const, text: `Session not found: ${sessionId}` }],
@@ -118,10 +118,10 @@ export function registerTools(server: McpServer, dbManager: McpDatabaseManager,
 
 function registerResources(server: McpServer, dbManager: McpDatabaseManager): void {
   server.resource('sessions-list', 'chatlab://sessions', { description: '所有已导入的聊天会话列表' }, async () => {
-    const sessionIds = dbManager.listSessionIdsReadonly()
+    const sessionIds = dbManager.listSessionIdsMcpReadonly()
     const sessions = sessionIds
       .map((id) => {
-        const db = dbManager.openReadonly(id)
+        const db = dbManager.openMcpReadonly(id)
         if (!db) return null
         try {
           const meta = getSessionMeta(db)
@@ -150,7 +150,7 @@ function registerResources(server: McpServer, dbManager: McpDatabaseManager): vo
     { description: '会话元信息（名称、平台、消息数等）' },
     async (uri, params) => {
       const sessionId = params.sessionId as string
-      const db = dbManager.openReadonly(sessionId)
+      const db = dbManager.openMcpReadonly(sessionId)
       if (!db) {
         return { contents: [{ uri: uri.href, text: '{"error": "Session not found"}', mimeType: 'application/json' }] }
       }
@@ -180,7 +180,7 @@ function registerResources(server: McpServer, dbManager: McpDatabaseManager): vo
     { description: '会话数据库的表结构' },
     async (uri, params) => {
       const sessionId = params.sessionId as string
-      const db = dbManager.openReadonly(sessionId)
+      const db = dbManager.openMcpReadonly(sessionId)
       if (!db) {
         return { contents: [{ uri: uri.href, text: '{"error": "Session not found"}', mimeType: 'application/json' }] }
       }
diff --git a/packages/mcp-server/src/types.ts b/packages/mcp-server/src/types.ts
index b6f74b37..74f6b084 100644
--- a/packages/mcp-server/src/types.ts
+++ b/packages/mcp-server/src/types.ts
@@ -9,10 +9,10 @@ import type { DatabaseAdapter } from '@openchatlab/core'
  * Both CLI's DatabaseManager and Desktop's helper can satisfy this contract.
  */
 export interface McpDatabaseManager {
-  /** List chat sessions without running schema migrations. */
-  listSessionIdsReadonly(): string[]
-  /** Open a non-cached, strictly read-only connection; caller must close it. */
-  openReadonly(sessionId: string): DatabaseAdapter | null
+  /** List only MCP-supported chat sessions; reject any requiring an upgrade. */
+  listSessionIdsMcpReadonly(): string[]
+  /** Open a non-cached, strictly read-only MCP connection after schema preflight; caller closes it. */
+  openMcpReadonly(sessionId: string): DatabaseAdapter | null
 }
 
 export interface McpServerOptions {
diff --git a/packages/node-runtime/src/database-manager.test.ts b/packages/node-runtime/src/database-manager.test.ts
index 64133464..2a444c7c 100644
--- a/packages/node-runtime/src/database-manager.test.ts
+++ b/packages/node-runtime/src/database-manager.test.ts
@@ -1328,3 +1328,152 @@ test('session deletion rejects a live topic execution owned by another runtime',
     reopened.close()
   }
 })
+
+test('read-only MCP schema preflight rejects all pending and future versions without touching database bytes', () => {
+  for (let version = 0; version <= CURRENT_SCHEMA_VERSION + 1; version++) {
+    const root = makeTempDir()
+    const provider = createPathProvider(root)
+    fs.mkdirSync(provider.getDatabaseDir(), { recursive: true })
+    const dbPath = path.join(provider.getDatabaseDir(), 'schema-check.db')
+    const db = new Database(dbPath, { nativeBinding })
+    try {
+      const versionColumn = version === 0 ? '' : ', schema_version INTEGER'
+      const versionValue = version === 0 ? '' : `, ${version}`
+      db.exec(`
+        CREATE TABLE meta (name TEXT, platform TEXT, type TEXT, imported_at INTEGER${versionColumn});
+        INSERT INTO meta VALUES ('Schema Check', 'qq', 'group', 1000${versionValue});
+        CREATE TABLE member (id INTEGER PRIMARY KEY, platform_id TEXT);
+        CREATE TABLE message (id INTEGER PRIMARY KEY, sender_id INTEGER, ts INTEGER, type INTEGER, content TEXT);
+      `)
+    } finally {
+      db.close()
+    }
+
+    const manager = new DatabaseManager(provider, {
+      nativeBinding,
+      runtime: { version: '0.37.6', kind: 'mcp' },
+    })
+    // Version 6+ requires an existing compatibility gate. In this test we
+    // establish it before read-only access so schema validation is isolated.
+    if (version >= 6) manager.raiseCurrentChatDbCompatibilityGate()
+    const beforeDb = fs.readFileSync(dbPath)
+    const markerPath = path.join(provider.getUserDataDir(), '.chatlab-meta.json')
+    const beforeMarker = fs.existsSync(markerPath) ? fs.readFileSync(markerPath) : null
+
+    if (version === CURRENT_SCHEMA_VERSION) {
+      const opened = manager.openMcpReadonly('schema-check')
+      assert.ok(opened)
+      assert.equal(opened.readonly, true)
+      opened.close()
+    } else {
+      const guidance = version < CURRENT_SCHEMA_VERSION ? /migrate it first/ : /newer schema/
+      assert.throws(
+        () => manager.openMcpReadonly('schema-check'),
+        (error: unknown) =>
+          error instanceof Error &&
+          error.message.includes(`schema v${version}`) &&
+          error.message.includes(`schema v${CURRENT_SCHEMA_VERSION}`) &&
+          guidance.test(error.message),
+        `unexpected schema v${version} should be rejected before query dispatch`
+      )
+    }
+
+    assert.deepEqual(fs.readFileSync(dbPath), beforeDb, `schema v${version} was modified`)
+    assert.deepEqual(fs.existsSync(markerPath) ? fs.readFileSync(markerPath) : null, beforeMarker)
+    manager.closeAll()
+  }
+})
+
+test('MCP reports future schemas accurately even if their compatibility marker is missing', () => {
+  const root = makeTempDir()
+  const provider = createPathProvider(root)
+  fs.mkdirSync(provider.getDatabaseDir(), { recursive: true })
+  const dbPath = path.join(provider.getDatabaseDir(), 'future.db')
+  const db = new Database(dbPath, { nativeBinding })
+  try {
+    db.exec(`
+      CREATE TABLE meta (
+        name TEXT, platform TEXT, type TEXT, imported_at INTEGER, schema_version INTEGER
+      );
+      INSERT INTO meta VALUES ('Future Chat', 'qq', 'group', 1000, ${CURRENT_SCHEMA_VERSION + 1});
+      CREATE TABLE member (id INTEGER PRIMARY KEY, platform_id TEXT);
+      CREATE TABLE message (id INTEGER PRIMARY KEY, sender_id INTEGER, ts INTEGER, type INTEGER, content TEXT);
+    `)
+  } finally {
+    db.close()
+  }
+  const before = fs.readFileSync(dbPath)
+  const manager = new DatabaseManager(provider, {
+    nativeBinding,
+    runtime: { version: '0.37.6', kind: 'mcp' },
+  })
+  assert.equal(readDataDirCompatibilityMeta(provider.getUserDataDir()), null)
+
+  assert.throws(
+    () => manager.openMcpReadonly('future'),
+    (error: unknown) =>
+      error instanceof Error &&
+      /newer schema/i.test(error.message) &&
+      /Upgrade the ChatLab runtime/i.test(error.message) &&
+      !/compatibility marker/i.test(error.message)
+  )
+  assert.throws(() => manager.listSessionIdsMcpReadonly(), /Upgrade the ChatLab runtime/i)
+  assert.deepEqual(fs.readFileSync(dbPath), before)
+  assert.equal(readDataDirCompatibilityMeta(provider.getUserDataDir()), null)
+  manager.closeAll()
+})
+
+test('MCP schema preflight rejects invalid SQLite version values without affecting shared reads', () => {
+  const cases: Array<{ label: string; sqlValue: string; sqlType: string }> = [
+    { label: 'text', sqlValue: "'not-a-version'", sqlType: 'text' },
+    { label: 'fractional', sqlValue: '10.5', sqlType: 'real' },
+    { label: 'negative', sqlValue: '-1', sqlType: 'integer' },
+    { label: 'unsafe integer', sqlValue: '9223372036854775807', sqlType: 'integer' },
+    { label: 'blob', sqlValue: "X'616263'", sqlType: 'blob' },
+  ]
+  for (const { label, sqlValue, sqlType } of cases) {
+    const root = makeTempDir()
+    const provider = createPathProvider(root)
+    fs.mkdirSync(provider.getDatabaseDir(), { recursive: true })
+    const dbPath = path.join(provider.getDatabaseDir(), 'invalid-version.db')
+    const fixture = new Database(dbPath, { nativeBinding })
+    try {
+      fixture.exec(`
+        CREATE TABLE meta (
+          name TEXT, platform TEXT, type TEXT, imported_at INTEGER,
+          schema_version INTEGER
+        );
+        INSERT INTO meta VALUES ('Legacy', 'qq', 'group', 1000, ${sqlValue});
+        CREATE TABLE member (id INTEGER PRIMARY KEY, platform_id TEXT, name TEXT, nickname TEXT);
+        CREATE TABLE message (id INTEGER PRIMARY KEY, sender_id INTEGER, ts INTEGER, type INTEGER, content TEXT);
+      `)
+      const stored = fixture.prepare('SELECT typeof(schema_version) AS storage FROM meta').get() as {
+        storage: string
+      }
+      assert.equal(stored.storage, sqlType, label)
+    } finally {
+      fixture.close()
+    }
+
+    const before = fs.readFileSync(dbPath)
+    const manager = new DatabaseManager(provider, {
+      nativeBinding,
+      runtime: { version: '0.37.6', kind: 'mcp' },
+    })
+    try {
+      // CLI auto-import relies on shared read-only access to legacy candidates.
+      assert.deepEqual(manager.listSessionIdsReadonly(), ['invalid-version'], label)
+      const shared = manager.openReadonly('invalid-version')
+      assert.ok(shared)
+      shared.close()
+
+      assert.throws(() => manager.openMcpReadonly('invalid-version'), /invalid schema version/i, label)
+      assert.throws(() => manager.listSessionIdsMcpReadonly(), /invalid schema version/i, label)
+      assert.deepEqual(fs.readFileSync(dbPath), before, `${label}: read must not alter the DB`)
+      assert.equal(readDataDirCompatibilityMeta(provider.getUserDataDir()), null, label)
+    } finally {
+      manager.closeAll()
+      fs.rmSync(root, { recursive: true, force: true })
+    }
+  }
+})
diff --git a/packages/node-runtime/src/database-manager.ts b/packages/node-runtime/src/database-manager.ts
index eaec3d99..99e923ec 100644
--- a/packages/node-runtime/src/database-manager.ts
+++ b/packages/node-runtime/src/database-manager.ts
@@ -133,16 +133,53 @@ export class DatabaseManager {
   }
 
   /**
-   * Open an uncached session database strictly for reading, without migrations or
-   * compatibility gate updates. The caller owns and must close the connection.
+   * Open an uncached session database strictly for reading, without migrations.
+   * This shared API is also used by CLI import analysis: do not require the
+   * current schema here. The caller owns and must close the connection.
    */
   openReadonly(sessionId: string): DatabaseAdapter | null {
     this.assertCompatible()
     if (!fs.existsSync(this.getDbPath(sessionId))) return null
+    return this.openRawSessionDatabase(sessionId, { readonly: true })
+  }
+
+  /**
+   * MCP-only strict read access. Never migrate or repair data. Older schema
+   * versions require an explicit upgrade through a writable ChatLab runtime.
+   */
+  openMcpReadonly(sessionId: string): DatabaseAdapter | null {
+    const db = this.openReadonly(sessionId)
+    if (!db) return null
 
-    const db = this.openRawSessionDatabase(sessionId, { readonly: true })
     try {
-      if (isChatSessionDb(db)) this.assertReadonlyCompatibilityGate(getSchemaVersion(db))
+      if (isChatSessionDb(db)) {
+        const schemaVersion = getSchemaVersion(db)
+        // SQLite INTEGER-affinity columns may actually contain TEXT, REAL or
+        // BLOB values. A type assertion cannot protect numeric comparisons
+        // from coercing invalid values (e.g. nonnumeric text to NaN).
+        if (!Number.isSafeInteger(schemaVersion) || schemaVersion < 0) {
+          throw new Error(
+            `ChatLab session ${sessionId} has an invalid schema version. ` +
+              'Cannot safely serve this database through read-only MCP tools.'
+          )
+        }
+        // The runtime cannot understand a future schema or safely repair its
+        // compatibility metadata; report the version mismatch before the gate.
+        if (schemaVersion > CURRENT_SCHEMA_VERSION) {
+          throw new Error(
+            `ChatLab session ${sessionId} uses schema v${schemaVersion}, but read-only MCP tools require ` +
+              `schema v${CURRENT_SCHEMA_VERSION}. Upgrade the ChatLab runtime to one that supports this newer schema.`
+          )
+        }
+
+        this.assertReadonlyCompatibilityGate(schemaVersion)
+        if (schemaVersion < CURRENT_SCHEMA_VERSION) {
+          throw new Error(
+            `ChatLab session ${sessionId} uses schema v${schemaVersion}, but read-only MCP tools require ` +
+              `schema v${CURRENT_SCHEMA_VERSION}. Open the session with the current writable ChatLab runtime to migrate it first.`
+          )
+        }
+      }
       return db
     } catch (error) {
       db.close()
@@ -228,6 +265,7 @@ export class DatabaseManager {
 
   /**
    * 只读列举聊天会话 ID，不触发数据库迁移或兼容门禁提升。
+   * CLI 导入预分析需要枚举未升级的旧库，因此不可强制当前 Schema。
    */
   listSessionIdsReadonly(): string[] {
     this.assertCompatible()
@@ -244,6 +282,21 @@ export class DatabaseManager {
     })
   }
 
+  /** MCP session discovery performs the same strict schema preflight as MCP queries. */
+  listSessionIdsMcpReadonly(): string[] {
+    this.assertCompatible()
+
+    return listDatabaseCandidateIds(this.pathProvider.getDatabaseDir()).filter((sessionId) => {
+      const db = this.openMcpReadonly(sessionId)
+      if (!db) return false
+      try {
+        return isChatSessionDb(db)
+      } finally {
+        db.close()
+      }
+    })
+  }
+
   getUserDataDir(): string {
     return this.pathProvider.getUserDataDir()
   }
diff --git a/tests/mcp-server.test.ts b/tests/mcp-server.test.ts
index f63117bf..a83e8040 100644
--- a/tests/mcp-server.test.ts
+++ b/tests/mcp-server.test.ts
@@ -41,8 +41,8 @@ test('MCP tools/list array schemas agree with tools/call validation and database
   await startMcpServer({
     version: '1.0.0',
     dbManager: {
-      listSessionIdsReadonly: () => ['fixture'],
-      openReadonly: (id) => (id === 'fixture' ? readonlyFixture : null),
+      listSessionIdsMcpReadonly: () => ['fixture'],
+      openMcpReadonly: (id) => (id === 'fixture' ? readonlyFixture : null),
     },
   })
   await client.connect(clientTransport)