fix(gate): match DDL by statement shape, not keyword adjacency

src/gate/test-presence.test.ts

@@ -40,6 +40,83 @@ describe("patchAddsQueryCode", () => {
     expect(patchAddsQueryCode(addPatch("const total = items.length + 1;"))).toBe(false);
   });
 
+  test("ignores DDL keywords in a prose string literal", () => {
+    // The Site#3539 false positive: an MCP tool description mentioning the
+    // fix it returns. Prose, not a statement — no ON clause, no column list.
+    expect(
+      patchAddsQueryCode(
+        addPatch(
+          '"each with its suggested CREATE INDEX fix, cost delta, and current triage status, ranked by impact.",',
+        ),
+      ),
+    ).toBe(false);
+  });
+
+  test("still detects statement-shaped DDL", () => {
+    expect(
+      patchAddsQueryCode(addPatch('"CREATE INDEX plans_project_id_idx ON plans (project_id)"')),
+    ).toBe(true);
+    expect(
+      patchAddsQueryCode(addPatch("const ddl = `CREATE TABLE widgets (id serial primary key)`;")),
+    ).toBe(true);
+    expect(patchAddsQueryCode(addPatch('"ALTER TABLE users ADD COLUMN age int"'))).toBe(true);
+    expect(patchAddsQueryCode(addPatch('"DROP TABLE IF EXISTS old_stuff"'))).toBe(true);
+  });
+
+  // The DDL recall the statement-shape rewrite must hold, shape by shape. Two
+  // variants are newly caught: the old adjacency pattern missed
+  // `CREATE UNIQUE INDEX CONCURRENTLY` and `CREATE OR REPLACE VIEW` (a word
+  // between the keywords broke it); the optional groups here cover them.
+  test("detects each DDL variant, including two the old pattern missed", () => {
+    const ddl = [
+      "CREATE UNIQUE INDEX CONCURRENTLY IF NOT EXISTS ix_email ON users (email);",
+      'CREATE INDEX "ix quoted" ON "user events" (occurred_at DESC);',
+      "CREATE TABLE IF NOT EXISTS widgets (id serial PRIMARY KEY, name text);",
+      "CREATE OR REPLACE VIEW active_users AS SELECT 1;",
+      "CREATE MATERIALIZED VIEW daily_stats AS SELECT 1;",
+      "ALTER TABLE users ADD COLUMN age int;",
+      'ALTER TABLE "users" DROP COLUMN age;',
+      "ALTER TABLE IF EXISTS users RENAME TO members;",
+      "DROP TABLE old_stuff;",
+      "DROP INDEX CONCURRENTLY ix_email;",
+      "DROP VIEW IF EXISTS active_users;",
+      "DROP MATERIALIZED VIEW daily_stats;",
+    ];
+    for (const stmt of ddl) {
+      expect(patchAddsQueryCode(addPatch(stmt)), stmt).toBe(true);
+    }
+  });
+
+  test("detects multi-line DDL through the query-call shapes", () => {
+    // The DDL patterns are same-line; DDL wrapped across lines still registers
+    // via the call that runs it (`.execute(` / sql``) on its opening line.
+    const patch =
+      "@@ -1,0 +1,3 @@\n" +
+      "+await db.execute(`\n" +
+      "+  CREATE INDEX idx_users_email\n" +
+      "+    ON users (email)`);";
+    expect(patchAddsQueryCode(patch)).toBe(true);
+  });
+
+  test("detects CREATE TABLE ... AS SELECT via the select shape", () => {
+    expect(
+      patchAddsQueryCode(addPatch("CREATE TABLE archive AS SELECT id FROM users;")),
+    ).toBe(true);
+  });
+
+  test("accepts the known miss: a bare multi-line DDL string with no query call", () => {
+    // Deliberate: the keyword line alone carries no statement grammar, and the
+    // gate is warn-only with an under-fire bias — a false positive costs trust,
+    // a miss here is covered by the capture rungs (#3502/#3503). This test pins
+    // the trade-off so a future change to it is a decision, not an accident.
+    const patch =
+      "@@ -1,0 +1,3 @@\n" +
+      "+const DDL =\n" +
+      "+  'CREATE INDEX idx_users_email' +\n" +
+      "+  ' ON users (email)';";
+    expect(patchAddsQueryCode(patch)).toBe(false);
+  });
+
   test("only looks at added lines, not removed ones", () => {
     const patch = "@@ -1,1 +1,1 @@\n-await db.select().from(users);\n+const x = 1;";
     expect(patchAddsQueryCode(patch)).toBe(false);
@@ -191,6 +268,30 @@ describe("evaluateTestPresence", () => {
     expect(verdict).toBeNull();
   });
 
+  test("does not fire on the tool-rename PR from Site#3539", () => {
+    // A rename PR rewrote a tool-registration line whose description string
+    // says "suggested CREATE INDEX fix" — prose, not a query. The touched spec
+    // files aren't data-layer tests and a rename captures no new hashes, so
+    // only the content heuristic can keep this PR clean.
+    const verdict = evaluateTestPresence(
+      [
+        changed(
+          "packages/mcp-server/src/tools/index.ts",
+          '"Review a CI run in one call: each with its suggested CREATE INDEX fix, cost delta, and current triage status.",',
+        ),
+        changed("packages/mcp-server/src/server.spec.ts", '"review_ci_run",'),
+        changed(
+          "packages/mcp-server/src/tools/ci/review-ci-run.spec.ts",
+          'const result = await runReviewCiRun({ runId: "run_1" }, client);',
+          "renamed",
+        ),
+      ],
+      undefined,
+      { newQueryHashes: [] },
+    );
+    expect(verdict).toBeNull();
+  });
+
   test("passes when the PR changes no query code", () => {
     const verdict = evaluateTestPresence([
       changed("apps/app/src/components/Button.tsx", "const label = props.label;"),

src/gate/test-presence.ts

@@ -77,7 +77,17 @@ export const DEFAULT_TEST_PRESENCE_CONFIG: TestPresenceConfig = {
     /\bdelete\s+from\b/i,
     /\bupdate\b[^\n]{0,80}\bset\b/i,
     /\bselect\b[\s\S]{0,300}?\bfrom\b/i,
-    /\b(create|alter|drop)\s+(table|index|view|materialized\s+view)\b/i,
+    // DDL is matched by statement shape (ON clause, column list, target
+    // identifier), not bare keyword adjacency: prose in a string literal —
+    // "its suggested CREATE INDEX fix" in an MCP tool description (Site#3539)
+    // — must not read as a query. Stripping string literals instead would
+    // blind the raw-SQL shapes above, since raw SQL lives in strings; the
+    // statement's own grammar is the discriminator.
+    /\bcreate\s+(unique\s+)?index\b[^\n]{0,120}?\bon\b/i,
+    /\bcreate\s+table\b[^\n]{0,80}?\(/i,
+    /\bcreate\s+(or\s+replace\s+)?(materialized\s+)?view\b[^\n]{0,80}?\bas\b/i,
+    /\balter\s+table\s+(if\s+exists\s+)?["\w]/i,
+    /\bdrop\s+(table|index|view|materialized\s+view)\s+(if\s+exists\s+|concurrently\s+)?["\w]/i,
   ],
   dataAccessPathPatterns: [
     /(^|\/)[^/]*repositor(y|ies)[^/]*\.[cm]?[jt]s$/i,