…mid-stream error

Appending a JSON error object to a partial JSON stream corrupts it
(e.g. {"foo":"ba{"error":"..."}) causing useObject to fail to parse.
Close the stream immediately instead, which triggers useObject's onError
callback on the client.

Also changes onError signature to (err: unknown) => void since the return
value was never meaningful in this context.

AiSdkChunkSchema → StreamChunkSchema (removes redundant vendor prefix)
ChatFlowOutputSchema → FlowOutputSchema (applies to both chat and completion)

Also renames the corresponding TypeScript types:
  AiSdkChunk → StreamChunk
  ChatFlowOutput → FlowOutput

Converts a Genkit GenerateResponseChunk to StreamChunk[] values ready to
pass to sendChunk(), eliminating boilerplate in flow implementations.

Handles text deltas, reasoning/thinking deltas, and tool-request parts.
Falls back to toolRequest.name when ref is not set.

Also uses toStreamChunks() in the vercel-ai-sdk-next testapp chat flow.

…elpers

toStreamChunks converts a GenerateResponseChunk into StreamChunk[] values
ready to pass to sendChunk(), handling text, reasoning, media parts, and
tool requests in the correct emission order.

toFlowOutput extracts finishReason and usage from a GenerateResponse,
eliminating the manual return boilerplate in flow definitions.

Update the testapp chat flow to use both helpers.

…vements

- Delete unused resolveContext utility (was exported but never called)
- Remove normalizeFinishReason/FinishReason from public API (internal detail)
- Unify onError to (err: unknown) => string | void across all three handlers;
  chat/completion use the return value, objectHandler ignores it (protocol
  constraint), but the signature is now consistent
- Make ChatHandlerOptions, CompletionHandlerOptions, ObjectHandlerOptions
  generic over Ctx for typed contextProvider implementations
- Remove backward-compat plain string dispatch from dispatchChunk; flows
  must use StreamChunkSchema typed chunks (plugin is unreleased, no compat needed)
- Replace as any casts in completion.ts text mode with StreamChunkSchema.safeParse
- Add explanatory comment for unavoidable data-* cast in dispatch.ts
- Throw on legacy UIMessage role 'tool' in toGenkitMessages with a clear
  message directing users to tool-invocation parts (AI SDK v4+ format)
- Add onError and mid-stream error tests for chatHandler and completionHandler
- Add finish-reason normalisation test (unknown reasons are silently omitted)
- Add tool role throw test to convert_test.ts
- Update testapp chat flow with getWeather tool and custom data chunk;
  update chat page to render tool-invocation and reasoning parts

- Fix JSDoc in chat.ts, completion.ts, dispatch.ts that still referenced
  removed z.string() plain-string streamSchema support
- Remove z re-export from schema.ts (peer dep, consumers already have it)
- Remove ContentPartSchema/ContentPart from public API (schema internals)
- Remove closeOpenBlocks/createDispatchState/dispatchChunk/DispatchState
  from public API (implementation details; can be re-exposed if needed)
- Replace hand-rolled GenkitMessageData/GenkitPart/etc shadow types in
  convert.ts with Genkit's authoritative MessageData and Part types;
  remove GenkitMessageData and GenkitPart from public exports
- Fix ContextProvider generic order: ContextProvider<Ctx, any> not
  ContextProvider<any, Ctx> — first param is context (return type),
  second is request input type; this also eliminates the as Record<string,unknown>
  casts that were papering over the wrong order

… in README

… alignment

Switch handler flow parameters from raw Zod Action types to structural
types with named interfaces (ChatFlowInput) so TypeScript errors say
"not assignable to ChatFlowInput" instead of expanding full Zod generic
walls. Update objectHandler to use structural ObjectFlow type for
consistency with chatHandler and completionHandler.

Update vendored UIMessage types from v4/v5 (tool-invocation, args/result)
to v6 format (dynamic-tool / tool-${name}, input/output fields with new
states: input-streaming, input-available, output-available, output-error,
output-denied).

Add 4 new StreamChunkSchema variants for v6 tool lifecycle events:
tool-input-error, tool-output-error, tool-output-denied, and
tool-approval-request — with full dispatch support in stream.ts.

Replace dispatch.ts/writer.ts with stream.ts using AI SDK's own
createUIMessageStream/createUIMessageStreamResponse for SSE lifecycle.

Add compile-time type checking (tests/type_check.ts) to verify handler
parameter constraints produce errors for wrong flow types.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

…losed stream

When the client aborts a request, the WritableStream may already be
closed by the time the finally block runs, causing an unhandled
ERR_INVALID_STATE rejection. Wrap writer.close() in a try/catch in
both objectHandler and completionHandler (text mode).

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>