[ustccjw001]

Adds per-call timing for Codex model requests, remote Worker requests/SSE subscriptions, retrieval/memory operations and database-backed session event persistence through the existing OTel provider/exporter. Storage timing preserves explicit database URL precedence and caller-owned services, measures ADK storage operations rather than individual SQL statements, and does not collect payloads or database URLs.

Restores ordinary MCP discovery/calls by avoiding recursive session locking, forwarding native ADK transport/session arguments and retaining non-vendor headers. Adds fixed-metadata mcp.tools.prepare and mcp.session.acquire spans to Trusted toolsets and native/VeIdentity instances assembled by VeADK Agent. Instance adaptation retains managers, callbacks, credentials, caches and retries; it is idempotent and deepcopy preserves copied ownership. Shared ADK classes and unrelated tools are unchanged. Overlapping preparation/acquisition durations must not be summed or interpreted as pure network time.

VeIdentity sends only current W3C traceparent/tracestate in each MCP request's meta, leaving credential headers and pool keys unchanged. No-span calls preserve the original shape; extraction failures do not block or repeat business calls. Retry logs retain function/error type without private exception text.

Synchronized to current main c1d4096, retaining its request/model/first-output timing documentation in both languages. The upstream explicit-URL regression now checks real SQLite session creation/readback and URL precedence rather than the old internal constructor mock. Documentation type checking generates Next route types before the MDX index, preventing an empty generated server module without changing compiler checks, dependencies or site configuration.

Validation on ecba26a:

• Full parallel Python regression: 8,050 passed, 50 skipped, four xfailed and 88 warnings in 442.61 seconds; codex_smoke and piagent_smoke excluded. Endpoint/persistence/model timing regression: 90 passed. All-files pre-commit passed, including both secret scanners and runtime dependency policy. The first full run's obsolete constructor-mock failure and its correction remain in the bilingual synchronization design.
• Python 3.12.14, Google ADK 2.7.1, OpenTelemetry 1.42.1 and MCP 1.26.0; runtime dependency metadata and lock files unchanged. Tested follow-up hashes and the production Python tree were checked after the final documentation commit.
• Documentation production build and the corrected types:check script passed. Initial TS2306 failures remain recorded; generated files were not patched.
• Earlier local HTTP MCP/archive/tracer fixture checks cover distinct per-call parents, context restoration, session close, wrong-base rejection and bootstrap tracer reuse. Earlier isolated cloud fixtures verify Trusted/native preparation and automatic Agent instrumentation in APMPlus. V28 uses synthetic model configuration and verifies the VeIdentity post-credential path; it does not invoke a real identity provider or model.
• Earlier SDK ASGI checks cover /run, /run_sse and /invoke with real SQLite saves under the request Trace/diagnostic Run. Receiver-side per-call association is tracked separately in feat(runtime): correlate request traces and execution timing agentkit-sdk-python#188.

Hosted verification workflows await maintainer approval; release workflows are outside this validation scope. Real credential-provider authorization, deployed direct-URL persistence, Sandbox internal phases and remote Worker receipt remain separate acceptance checks. Non-streaming calls do not provide model TTFT; SSE duration includes consumer time. Draft only; no merge, publication or deployment.