packages/typescript/ai/tests/stream-processor.test.ts (1)

778-830: Add one signature propagation regression here.

These new cases cover stepId, but none assert that a STEP_FINISHED.signature survives into the stored thinking part. That field is what Anthropic needs on the follow-up turn, so this branch is still unguarded by tests.

Test sketch

+    it('should persist signature on a thinking step', () => {
+      const processor = new StreamProcessor()
+      processor.prepareAssistantMessage()
+
+      processor.processChunk(
+        chunk('STEP_FINISHED', {
+          stepId: 'step-1',
+          delta: 'thinking...',
+          signature: 'sig-1',
+        }),
+      )
+
+      expect(processor.getMessages()[0]?.parts[0]).toEqual({
+        type: 'thinking',
+        content: 'thinking...',
+        stepId: 'step-1',
+        signature: 'sig-1',
+      })
+    })

🤖 Prompt for AI Agents

Verify each finding against the current code and only fix it if needed.

In `@packages/typescript/ai/tests/stream-processor.test.ts` around lines 778 -
830, Add assertions to the tests that verify STEP_FINISHED.signature is
propagated into the stored thinking parts and into the aggregated
state.thinking: when using StreamProcessor.processChunk with
ev.stepFinished(..., stepId) include a signature value and assert that (from
processor.getMessages()[0]!.parts filtered by type 'thinking') each thinking
part has the same signature (e.g., for 'step-1' and 'step-2'), and in the
getResult()/getState() concatenation case assert that state.thinking retains
each step's signature information (or that the per-step signatures are
accessible on the stored thinking parts); locate code via
StreamProcessor.processChunk, ev.stepFinished, processor.getMessages, and
processor.getState to add these checks.

packages/typescript/ai-anthropic/src/adapters/text.ts (2)

395-405: Thinking blocks without signatures are silently filtered out.

The loop only pushes thinking blocks that have a signature. This is correct per Anthropic's API requirements (signatures are mandatory for replaying thinking in multi-turn context), but a brief comment explaining this would help maintainability.

📝 Suggested comment

 if (message.thinking?.length) {
   for (const thinking of message.thinking) {
+    // Anthropic requires signatures to replay thinking blocks in multi-turn context;
+    // blocks without signatures cannot be included.
     if (thinking.signature) {
       contentBlocks.push({

🤖 Prompt for AI Agents

Verify each finding against the current code and only fix it if needed.

In `@packages/typescript/ai-anthropic/src/adapters/text.ts` around lines 395 -
405, Add a short explanatory comment above the loop that filters thinking blocks
to clarify that only thinking entries with a signature are included because
Anthropic requires signatures to replay thinking in multi-turn context;
reference the variables message.thinking, thinking.signature, the
contentBlocks.push of AnthropicContentBlock, and note that omitting unsigned
thinking blocks is intentional for API compliance and not a bug.

---

292-295: Add a comment explaining the beta header requirement and type assertion.

The beta header interleaved-thinking-2025-05-14 is required to enable interleaved thinking in Claude models during tool-use conversations. Add a brief comment explaining why this beta is needed and why the as any cast is used (the Anthropic SDK types don't include betas in this parameter definition).

🤖 Prompt for AI Agents

Verify each finding against the current code and only fix it if needed.

In `@packages/typescript/ai-anthropic/src/adapters/text.ts` around lines 292 -
295, Add an inline comment above the conditional that sets betas explaining that
the beta header "interleaved-thinking-2025-05-14" is required to enable
interleaved thinking for Claude during tool-use conversations, and note that the
`as any` cast is used because the Anthropic SDK types do not include `betas` on
this parameter; update the block around the `thinkingBudget` conditional and the
`betas` property to include that short explanatory comment next to `betas` and
`as any` so future readers understand both the runtime requirement and the
type-workaround.

packages/typescript/smoke-tests/e2e/tests/thinking.spec.ts (2)

48-51: Tighten types on getMessages and filter callbacks.

The Array<any> return type and the (p: any) predicates throughout the tests disable type-checking on the assertions (e.g. assistantMessage.parts, firstStep.content, firstStep.signature). Since UIMessage is already exported from @tanstack/ai-client and used in mock.tsx, importing it here would catch shape regressions (e.g. if ThinkingPart.signature is renamed) at compile time rather than flakily at runtime.

Suggested change

-import { test, expect, type Page } from '@playwright/test'
+import { expect, test } from '@playwright/test'
+import type { Page } from '@playwright/test'
+import type { UIMessage } from '@tanstack/ai-client'
@@
-async function getMessages(page: Page): Promise<Array<any>> {
+async function getMessages(page: Page): Promise<Array<UIMessage>> {
   const jsonContent = await page.locator('#messages-json-content').textContent()
   return JSON.parse(jsonContent || '[]')
 }

This also addresses the ESLint sort-imports and import/consistent-type-specifier-style hints on line 1.

🤖 Prompt for AI Agents

Verify each finding against the current code and only fix it if needed.

In `@packages/typescript/smoke-tests/e2e/tests/thinking.spec.ts` around lines 48 -
51, Tighten the types by importing UIMessage from "@tanstack/ai-client" and
update getMessages to return Promise<UIMessage[]> (change the function signature
and JSON parse typing), then replace loose any usages in filter/map callbacks
(e.g., predicates like (p: any)) with the concrete UIMessage type and update
assertions to use the typed properties (e.g., assistantMessage.parts,
firstStep.content, firstStep.signature) so TypeScript catches shape/regression
changes; ensure imports follow the project's import style to address
sort-imports and import/consistent-type-specifier-style hints.

---

115-122: afterEach is outside the describe block.

The test.afterEach hook at line 115 is declared after the describe closes on line 113, so it attaches to the root file scope rather than the Chat E2E Tests - Multi-Step Thinking (Mock API) group. That's functionally fine today (only one describe block in this file), but if additional describes are added later the screenshot hook will run for all of them, which may or may not be intended. Consider moving it inside the describe for clearer scoping.

Suggested change

 test.describe('Chat E2E Tests - Multi-Step Thinking (Mock API)', () => {
   ...
+
+  test.afterEach(async ({ page }, testInfo) => {
+    if (testInfo.status !== testInfo.expectedStatus) {
+      await page.screenshot({
+        path: `test-results/failure-${testInfo.title.replace(/\s+/g, '-')}.png`,
+        fullPage: true,
+      })
+    }
+  })
 })
-
-test.afterEach(async ({ page }, testInfo) => {
-  if (testInfo.status !== testInfo.expectedStatus) {
-    await page.screenshot({
-      path: `test-results/failure-${testInfo.title.replace(/\s+/g, '-')}.png`,
-      fullPage: true,
-    })
-  }
-})

🤖 Prompt for AI Agents

Verify each finding against the current code and only fix it if needed.

In `@packages/typescript/smoke-tests/e2e/tests/thinking.spec.ts` around lines 115
- 122, The screenshot cleanup hook test.afterEach is currently declared outside
the describe "Chat E2E Tests - Multi-Step Thinking (Mock API)" so it attaches to
the root scope; move the test.afterEach block inside that describe (before its
closing brace) so the hook is scoped to that describe only, preserving the same
screenshot logic and parameters (page, testInfo) and keeping the filename
generation code unchanged.

packages/typescript/smoke-tests/e2e/src/routes/api.mock-chat.ts (1)

310-394: Two STEP_FINISHED events per step — intentional but worth a comment.

Each thinking step emits STEP_FINISHED twice (first with a delta, then with content + signature). This appears to intentionally simulate streaming deltas followed by a final summary event, but STEP_FINISHED conventionally fires once per step. Since the PR's tests pass and rely on both events being processed (final signature stored on the step), consider adding a brief inline comment documenting that the first STEP_FINISHED carries the incremental delta and the second carries the final content/signature, so future readers don't mistake it for a duplicate event bug.

Also: the Date.now() calls in the chunk literals are evaluated at module load time; createMockStream already overrides timestamp on yield (line 407), so these initial values are dead — not a defect, just noise. Consider using a placeholder like timestamp: 0 for the static chunks to make that clearer.

🤖 Prompt for AI Agents

Verify each finding against the current code and only fix it if needed.

In `@packages/typescript/smoke-tests/e2e/src/routes/api.mock-chat.ts` around lines
310 - 394, Add a short inline comment above the "thinking-multi-step" mock
describing that each thinking step intentionally emits two STEP_FINISHED events
(first carrying the streaming delta, second carrying final content+signature) so
readers don't treat it as a duplicate; also replace the Date.now() timestamps in
the chunk literals with a placeholder like 0 since createMockStream overrides
timestamps at yield (see "thinking-multi-step", STEP_FINISHED entries and
createMockStream).

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes