docs(tools): correct tool APIs, auth config, and MCP lifecycle

[GWeale]

Corrects drifted API references across the tools pages: imports and attributes that do not exist in v2.5.0, a removed connection-lifecycle pattern, and examples the framework rejects at construction.

Changes

• docs/tools-custom/authentication.md — the Google API example imported calendar_tool_set, which does not exist (now CalendarToolset, plus GoogleApiToolSet → GoogleApiToolset); the external-access-token example passed google_credentials_config to AuthCredential, now BigQueryCredentialsConfig(external_access_token_key=...). Also tool_context.state rather than tool_context.invocation_context.session.state, get_auth_response(auth_config) takes an argument, corrected service_account_credential / scopes requiredness, true → True, and adds BaseCredentialService and AuthenticatedFunctionTool.
• docs/tools-custom/index.md — documented ToolContext.function_call_event_id and auth_response attributes that do not exist; replaced with invocation_id, agent_name, and get_auth_response(auth_config). Notes the artifact/memory methods are async, and documents the tool_filter / tool_name_prefix options on the BaseToolset constructor.
• docs/tools-custom/mcp-tools.md — the exit_stack cleanup pattern is gone; replaced with await toolset.close() / await runner.close(). Fixes MCPToolset → McpToolset, getstate/setstate → __getstate__/__setstate__, the MCP package name (mcp), the minimum Python (3.10), removes a --staging_bucket flag from the deploy command, and adds StreamableHTTPConnectionParams, the tool_filter predicate form, and the experimental to_mcp_server.
• docs/tools-custom/function-tools.md — claimed Optional[T] / | None alone makes a parameter optional (it does not; only a default does) and that LongRunningFunctionTool streams generator yields (it calls the function once and does not consume yields). Adds Pydantic-model parameters, AgentTool.include_plugins, and a note that Python prefers a single_turn sub-agent over AgentTool.
• docs/tools/limitations.md — the examples pairing BuiltInCodeExecutor / url_context with gemini-flash-latest raise a ValueError at construction; pinned to gemini-2.5-flash with a note explaining the gate. Also documents propagate_grounding_metadata on AgentTool and that bypass_multi_tools_limit must be set on a tool instance you construct yourself.
• docs/tools-custom/openapi-tools.md, docs/tools-custom/confirmation.md — RestApiTool executes asynchronously via httpx, not requests; and a corrected path to the moved confirmation sample.

The gemini-2.5-flash pins in limitations.md are a deliberate exception to this repo's preference for -latest aliases: those two features reject the alias, so the examples cannot run as written otherwise.

How this was produced

Part of a page-by-page audit of the Python docs against the google/adk-python v2.5.0 source: every import resolved against a real 2.5.0 install, every constructor kwarg checked against model_fields / inspect.signature, every documented default read off the field. A second independent pass re-derived each claim from source rather than trusting the finding, and a third conformed the new wording to the surrounding pages. mkdocs build --strict is clean.

Only Python tabs and language-neutral prose were touched — this audit had no ground truth for the Go / Java / TypeScript SDKs.

Split out of a larger audit branch so each area can be reviewed on its own.

[netlify]

✅ Deploy Preview for adk-docs-preview ready!

Name	Link
🔨 Latest commit	4d67c6a
🔍 Latest deploy log	https://app.netlify.com/projects/adk-docs-preview/deploys/6a6a999576d46000089576a5
😎 Deploy Preview	https://deploy-preview-2025--adk-docs-preview.netlify.app
📱 Preview on mobile	Toggle QR Code... Use your smartphone camera to open QR code link.
🤖 Make changes	Run an agent on this branch

---

To edit notification comments on pull requests, go to your Netlify project configuration.