@tanstack/ai@0.63.0

Minor Changes

• #1509 37b2826 - Add an optional inputSchema to defineAgent. The agent's tool shows the schema to the model, so the parent model writes the child's input, such as a short brief. run gets the checked input as a typed ctx.input. A bad input goes back to the model as a tool error, and the child does not start. inputSchema needs tool mode: chat() throws when subagents.router meets an agent that has one. Agents without inputSchema do not change.

• #1401 c5c1996 - Preserve structured outcomes for cancelled and denied tool results. A tool-result part now carries outcome: 'cancelled' | 'denied' (new ToolResultOutcome type and isToolResultOutcome guard) across tool execution, streaming, persistence, and UI restoration, so callers can tell a user or middleware decision from an ordinary tool failure without matching error text. state stays 'error' for these results. The @tanstack/ai-client ToolResultPart type (used by useChat messages) now has the same outcome field.

• #1452 0eb8f0b - @tanstack/ai-mcp can create an MCP server with createMCPServer and serveMCPStdio. The client package moves from @modelcontextprotocol/sdk to @modelcontextprotocol/client and @modelcontextprotocol/server. The client tries spec 2026-07-28 first, then the 2025 handshake. When an MCP server asks for input, chat() pauses with an mcp_input interrupt. Answer it with resolveInterrupt or cancel(), and the tool runs again with the answer in ctx.inputResponse. A tool can set execution: 'task' for a spec 2025 task handle. A tool reads requestInput and sample on ctx.context, typed by MCPToolContext. The server auth option takes the MCP SDK OAuthTokenVerifier shape. jwtVerifier and introspectionVerifier cover JWT and opaque tokens, and a tool reads the token as ctx.context.authInfo. createMCPClient<typeof server>({ transport }) types a remote client from a createMCPServer server, and createMCPClient({ server }) calls a server in the same process. server.handle(request, { authInfo, context }) takes a token your own middleware verified and values for ctx.context, typed with MCPToolContext<{ db: Db }>. A tool's metadata.title and metadata.annotations reach the host as the MCP title and annotations. A tool with no outputSchema can return a CallToolResult as is. sessions: 'reject' turns spec 2025 sessions off for hosts with many instances.

Patch Changes

• #1233 8e8ee26 - Preserve failed client tool results across native interrupt resumes and await asynchronous client output validation

• #1512 3e30cde - Keep a tool-call part at complete when its result arrives before the stream ends. If a stream had no TOOL_CALL_END, the end-of-stream safety net set a finished tool-call part back to input-complete. The final state then depended on async timing.

• #1528 f44b6b2 - otelMiddleware({ captureContent: true }) now records content on media spans (generateImage, generateVideo, generateAudio, generateSpeech, generateTranscription, and the others). gen_ai.input.messages gets the prompt and input media. gen_ai.output.messages gets the output URLs or the transcript text. Inline data stays a placeholder. redact and maxContentLength apply to each text part.

• #1527 d632d41 - otelMiddleware with captureContent: true now keeps multimodal parts structured in gen_ai.input.messages (OTel GenAI part shapes). URL media becomes a uri part and provider file handles become a file part, so traces show what the model looked at. Inline base64 data still records a [image]-style placeholder.