feat: AG-UI core interop - spec-compliant event types (#411)

* feat(ai): add @ag-ui/core as dependency for spec-compliant event types

* feat(ai): redefine AG-UI event types extending @ag-ui/core

Replace custom AG-UI event types with interfaces that extend @ag-ui/core
types for spec compliance. This is the foundational type change for the
AG-UI protocol alignment.

- Import all event types from @ag-ui/core with AGUI* aliases
- Replace BaseAGUIEvent to extend @ag-ui/core BaseEvent
- Replace each event interface to extend its @ag-ui/core equivalent
- Add TanStack-internal extension fields (model, deprecated aliases)
- Add new event types: ToolCallResultEvent, Reasoning* events
- Deprecate AGUIEventType in favor of EventType enum
- Re-export EventType enum from @ag-ui/core
- Add threadId/runId to TextOptions interface
- Update AGUIEvent union and StreamChunk type alias

* feat(ai): add stripToSpec middleware to strip non-spec fields from stream events

Creates a middleware that removes TanStack-internal extension fields
(model, rawEvent, deprecated aliases) from StreamChunk events so the
yielded stream is @ag-ui/core spec-compliant. Registered as the last
middleware in the chat activity chain so devtools and user middleware
still see the full extended events.

* feat(ai): plumb threadId and runId through chat() to adapters

Add threadId/runId to TextActivityOptions interface and TextEngine class
so they flow from user-facing chat() options through to adapter.chatStream().
ThreadId is auto-generated if not provided. Adapters will consume these
in subsequent tasks to include them in RUN_STARTED/RUN_FINISHED events.

* feat(ai-openai): update text adapter for AG-UI spec compliance

Add threadId to RUN_STARTED/RUN_FINISHED events, toolCallName to
TOOL_CALL_START/TOOL_CALL_END, stepName to STEP_STARTED/STEP_FINISHED,
flatten RUN_ERROR with top-level message/code fields, and emit
REASONING_START/MESSAGE_START/CONTENT/MESSAGE_END/END events alongside
legacy STEP events for reasoning content.

* fix: update tests and fix type errors for AG-UI spec compliance

Update test utilities and tests to use AG-UI spec field names:
- Add threadId to RUN_STARTED/RUN_FINISHED events
- Add toolCallName alongside deprecated toolName on tool events
- Add stepName alongside deprecated stepId on step events
- Use flat message field on RUN_ERROR (with deprecated error nested form)

Fix critical bugs discovered during testing:
- StreamProcessor: prefer chunk.message over chunk.error?.message for RUN_ERROR
- TextEngine: process original chunks for internal state before middleware strips fields
- Remove auto-applied stripToSpecMiddleware from chat() (breaks internal state since
  it strips finishReason, delta, content needed by TextEngine and StreamProcessor)
- Fix type compatibility issues with @ag-ui/core EventType enum vs string literals

Also fix type errors in:
- stream-generation-result.ts: use EventType enum and add threadId
- generateVideo/index.ts: add StreamChunk casts and threadId
- tool-calls.ts: cast TOOL_CALL_END yield to ToolCallEndEvent
- devtools-middleware.ts: handle toolCallName fallback and RUN_ERROR message field
- processor.ts: handle developer role, Messages snapshot type cast, finishReason undefined

* fix(ai): re-add stripToSpec middleware, process raw chunks internally, fix test assertions

* fix(ai): pipe tool-phase events through middleware, strip toolCallName, fix type errors

- Fix EventType enum vs string literal type errors in test files by
  relaxing chunk helper type params and adding cast helpers
- Pipe tool-phase events (TOOL_CALL_END, TOOL_CALL_RESULT, CUSTOM)
  through the middleware pipeline so strip-to-spec and devtools
  middleware observe all events, not just model-stream events
- Add toolCallName to TOOL_CALL_END strip set in strip-to-spec
  middleware since AG-UI spec ToolCallEndEvent only has toolCallId
- Update test assertions to use TOOL_CALL_RESULT (spec event) instead
  of checking stripped fields on TOOL_CALL_END

* style: format test files

* test(ai): add tests for REASONING events, TOOL_CALL_RESULT, threadId, and strip compliance

* fix: resolve eslint, type, and test failures across all packages

- Fix 5 ESLint errors in @tanstack/ai (array-type, no-unnecessary-condition,
  no-unnecessary-type-assertion, sort-imports)
- Fix ESLint error in @tanstack/ai-event-client (no-unnecessary-condition)
- Fix string literal vs EventType enum type errors across all 7 adapter
  packages by adding asChunk helper that casts event objects to StreamChunk
- Fix @tanstack/ai-client source type errors (chunk.error possibly undefined,
  runId access on RUN_ERROR events, connection-adapters push calls)
- Fix @tanstack/ai-client and @tanstack/ai-openrouter test type errors
- Fix tool-call-manager tests to use toolCallName instead of deprecated toolName

* fix: resolve eslint and test failures from strip-to-spec middleware

Remove assertions for fields (content, finishReason, usage) that the
stripToSpec middleware now strips from emitted events. Fix unnecessary
nullish coalescing in ai-openai and add type casts in ai-vue tests.

* fix: honor caller runId, prevent duplicate thinking, add error IDs, fix reasoning ordering

- Honor caller-provided runId/threadId in all 7 adapters using ?? fallback
- Prevent duplicate thinking content from dual STEP_FINISHED/REASONING_MESSAGE_CONTENT events
- Assert exact threadId value in chat test instead of just toBeDefined
- Add runId/threadId to RUN_ERROR in generateVideo and stream-generation-result
- Move reasoning processing before content processing in OpenRouter adapter

* fix(smoke-tests): update harness to read spec-compliant event fields

TOOL_CALL_START now uses toolCallName (spec) instead of toolName (deprecated).
TOOL_CALL_END fields (toolName, input, result) are stripped by spec middleware;
harness now falls back to data captured during START/ARGS phases.
Added TOOL_CALL_RESULT handler for spec-compliant tool result delivery.
RUN_FINISHED finishReason/usage are optional extensions.

* ci: apply automated fixes

* fix(smoke-tests): remove unnecessary as-any casts, use proper type narrowing

* ci: apply automated fixes

* fix(ai-ollama): emit TOOL_CALL_ARGS before TOOL_CALL_END for spec compliance

Ollama doesn't stream tool args incrementally — it delivers them all at once
in TOOL_CALL_END.input. Since the strip middleware removes input from
TOOL_CALL_END, consumers had no way to get the args. Now emits a
TOOL_CALL_ARGS event with the full args as delta before TOOL_CALL_END.

* fix(ai): hide strip-to-spec middleware from devtools instrumentation

* fix(ai): handle TOOL_CALL_RESULT in StreamProcessor to create tool-result parts

Root cause: The strip middleware removes 'result' from TOOL_CALL_END events.
The StreamProcessor's TOOL_CALL_END handler only creates tool-result parts
when chunk.result is present. With it stripped, no tool-result parts were
created on the client side.

TOOL_CALL_RESULT events (spec-compliant tool result delivery) were received
but ignored (no-op). Without tool-result parts, areAllToolsComplete() behaved
incorrectly, and the client could not detect server tool completion.

Fix: Handle TOOL_CALL_RESULT by creating tool-result parts and updating
tool-call output, mirroring TOOL_CALL_END's result handling logic.

* fix(ai): stop stripping finishReason from RUN_FINISHED events

finishReason is essential for client-side continuation logic. Without it,
the chat-client cannot distinguish 'stop' (no continuation needed) from
'tool_calls' (client tools need execution), causing infinite request loops
when server-side tool results leave tool-call parts as the last message part.

* fix(ai): only strip deprecated aliases and rawEvent, keep all extras

@ag-ui/core BaseEventSchema uses .passthrough(), so extra fields are allowed
and won't break spec validation. Only strip:
- Deprecated aliases: toolName, stepId, state (nudge toward spec names)
- Deprecated nested error object on RUN_ERROR
- rawEvent (debug payload, potentially large)

Keep everything else: model, content, args, usage, finishReason, input,
result, index, providerMetadata, stepType, delta, etc.

* ci: apply automated fixes

* fix(ai): stop stripping fields — passthrough allows all extras

@ag-ui/core BaseEventSchema uses .passthrough() so extra fields are allowed.
Only strip the deprecated nested error object from RUN_ERROR (conflicts with
spec's flat message/code). Everything else passes through: model, content,
toolName, stepId, usage, finishReason, result, input, args, etc.

* fix: resolve type errors from @ag-ui/core Zod passthrough types

Zod passthrough adds `& { [k: string]: unknown }` to inferred types,
preventing TypeScript from narrowing the `type` discriminant in switch
statements. Add explicit casts where needed. Also fix toolCallName ->
toolName rename in realtime types to match consumer code.

* ci: apply automated fixes

* chore(ai): bump @ag-ui/core from 0.0.48 to 0.0.49

Removes rxjs from the transitive dependency tree. All exported types
and EventType enum values are identical between versions.

* fix: CR fixes for AG-UI core interop

- Use this.threadId in createSyntheticFinishedEvent instead of
  regenerating a new ID on each call
- Add defensive delta guard in handleReasoningMessageContentEvent
  matching sibling handler patterns
- Prefer spec chunk.message over deprecated chunk.error in devtools
  middleware, generation client, and video generation client
- Add flat message field to synthesized RUN_ERROR in connection adapters
- Fix processChunk JSDoc listing RUN_STARTED as ignored (it has a handler)
- Fix comment referencing toolName when code uses toolCallName
- Document RUN_ERROR in stream-generation-result @returns
- Add meaningful assertions to TOOL_CALL_RESULT processor test
- Clarify threadId test describes adapter passthrough behavior

* ci: apply automated fixes

* fix(ai-client): use cast for RUN_ERROR message to satisfy eslint

chunk.message is typed as required string by @ag-ui/core but may be
absent at runtime from events constructed via as-unknown casts.
Cast to string|undefined to allow the || fallback chain while keeping
the no-unnecessary-condition rule happy.

* fix(ai): add StreamChunk casts for TOOL_CALL_START/ARGS in continuation re-executions

The merge from main brought in #372 which emits these events but used
string literals instead of the AGUIEvent enum, breaking the build.

* fix(ai-openrouter): prevent duplicate TEXT_MESSAGE_END and RUN_FINISHED events

OpenAI-compatible APIs often send two chunks with finishReason — one for
the finish signal and a separate trailing chunk carrying usage data.  The
adapter had no guard against this, causing TEXT_MESSAGE_END and
RUN_FINISHED to be emitted twice per run.

Root cause: processChoice emitted finish events on every finishReason
occurrence without tracking whether they had already been sent.

Fix:
- Add hasEmittedRunFinished / hasEmittedTextMessageEnd guards to AGUIState
- Accumulate usage from any finishReason chunk into deferredUsage
- Move RUN_FINISHED emission to after the stream loop so it always
  carries the latest usage data (even when it arrives on a later chunk)

Adds tests for duplicate-finish-chunk scenarios, usage preservation, and
event ordering.

* fix(ai-openrouter, ai): emit single STEP_FINISHED per reasoning block, remove [DONE] sentinel

STEP_FINISHED was emitted on every reasoning delta (N events for N
deltas) but only one STEP_STARTED was emitted, causing verifiers to
report orphan STEP_FINISHED events.  Move the single STEP_FINISHED to
the point where reasoning closes (before text starts or at stream end)
so every STEP_STARTED has exactly one matching STEP_FINISHED.

Remove the `data: [DONE]\n\n` sentinel from toServerSentEventsStream.
The AG-UI protocol already uses RUN_FINISHED as the terminal event, so
the [DONE] marker is redundant and forces every client to special-case
non-JSON data in the SSE stream.  Client-side parsers still tolerate
[DONE] for backward compatibility with external servers.

* fix(ai-client): warn when receiving deprecated [DONE] sentinel

Old servers still emit `data: [DONE]\n\n` after the stream.  The client
already skips it, but now logs a deprecation warning so users know to
upgrade their @tanstack/ai server package.

---------

Co-authored-by: autofix-ci[bot] <114827586+autofix-ci[bot]@users.noreply.github.com>

Author: AlemTuzlak

packages/typescript/ai-anthropic/src/adapters/summarize.ts

@@ -12,6 +12,10 @@ import type {
 } from '@tanstack/ai'
 import type { AnthropicClientConfig } from '../utils'
 
+/** Cast an event object to StreamChunk. */
+const asChunk = (chunk: Record<string, unknown>) =>
+  chunk as unknown as StreamChunk
+
 /**
  * Configuration for Anthropic summarize adapter
  */
@@ -103,18 +107,18 @@ export class AnthropicSummarizeAdapter<
         if (event.delta.type === 'text_delta') {
           const delta = event.delta.text
           accumulatedContent += delta
-          yield {
+          yield asChunk({
             type: 'TEXT_MESSAGE_CONTENT',
             messageId: id,
             model,
             timestamp: Date.now(),
             delta,
             content: accumulatedContent,
-          }
+          })
         }
       } else if (event.type === 'message_delta') {
         outputTokens = event.usage.output_tokens
-        yield {
+        yield asChunk({
           type: 'RUN_FINISHED',
           runId: id,
           model,
@@ -129,7 +133,7 @@ export class AnthropicSummarizeAdapter<
             completionTokens: outputTokens,
             totalTokens: inputTokens + outputTokens,
           },
-        }
+        })
       }
     }
   }