Add OpenTelemetry GenAI instrumentation to Copilot SDK

[stephentoub]

Introduced built-in OpenTelemetry tracing and metrics for agent turns and tool executions, following GenAI semantic conventions (v1.40).

[Copilot]

Pull request overview

Adds built-in, opt-in OpenTelemetry tracing + metrics across the SDKs (Node/TS, Python, Go, .NET), emitting spans/metrics that follow the GenAI semantic conventions (v1.40) for agent turns and tool executions.

Changes:

• Introduces TelemetryConfig in each SDK and wires it into client/session creation (opt-in).
• Instruments invoke_agent turns and execute_tool calls with spans + GenAI metrics (duration, token usage, streaming timing).
• Updates docs and adds/updates tests demonstrating expected telemetry output and sensitive-data gating.

Reviewed changes

Copilot reviewed 35 out of 37 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
python/pyproject.toml	Adds OpenTelemetry API/SDK deps (API runtime, SDK in dev extras).
python/copilot/types.py	Adds TelemetryConfig + agent attribution fields to session configs.
python/copilot/session.py	Starts/updates per-turn telemetry tracking and captures tool descriptions.
python/copilot/client.py	Initializes telemetry (opt-in), passes context to sessions, instruments tool calls.
python/copilot/_copilot_telemetry.py	Implements Python-side GenAI OTel spans/metrics + per-turn tracker.
python/copilot/init.py	Exposes TelemetryConfig from the Python package API surface.
python/README.md	Documents telemetry and agent attribution options for Python users.
nodejs/test/opentelemetry.test.ts	Adds unit tests validating Node telemetry spans/metrics and gating behavior.
nodejs/src/types.ts	Adds TelemetryConfig + agent attribution fields to TS public types.
nodejs/src/session.ts	Adds per-turn telemetry tracking hooks and tool description registry.
nodejs/src/index.ts	Re-exports TelemetryConfig type.
nodejs/src/copilot-telemetry.ts	Implements Node-side GenAI OTel spans/metrics + per-turn tracker.
nodejs/src/client.ts	Initializes telemetry (opt-in) and instruments tool execution with child spans + metrics.
nodejs/package.json	Adds OTel JS API dependency and SDK devDependencies for tests.
nodejs/package-lock.json	Locks new OTel dependencies.
nodejs/README.md	Documents telemetry + agent attribution options for Node users.
go/types.go	Adds telemetry + agent attribution fields to Go options/config types.
go/session.go	Adds tool descriptions + per-turn telemetry hooks and session telemetry context setup.
go/go.sum	Adds sums for new OpenTelemetry Go dependencies.
go/go.mod	Adds OpenTelemetry Go modules and toolchain metadata.
go/copilot_telemetry_consts.go	Defines GenAI semconv constants + metric bucket boundaries for Go.
go/copilot_telemetry.go	Implements Go-side GenAI OTel spans/metrics + per-turn tracker.
go/client.go	Wires telemetry into client/session creation and tool execution instrumentation.
go/README.md	Documents telemetry + agent attribution options for Go users.
dotnet/test/OpenTelemetryTests.cs	Adds E2E tests validating .NET telemetry spans/metrics and gating behavior.
dotnet/test/Harness/E2ETestContext.cs	Allows creating clients with/without telemetry in the .NET harness.
dotnet/test/GitHub.Copilot.SDK.Test.csproj	Adds in-memory OTel exporter dependency for tests.
dotnet/src/Types.cs	Adds TelemetryConfig + agent attribution fields to .NET option/config types.
dotnet/src/Session.cs	Integrates per-turn tracker and telemetry completion on send/wait failures.
dotnet/src/OpenTelemetryConsts.cs	Adds GenAI semconv constants + metric boundaries for .NET.
dotnet/src/CopilotTelemetry.cs	Implements .NET telemetry (ActivitySource + Meter) and per-turn tracker.
dotnet/src/Client.cs	Creates telemetry instance (opt-in), instruments execute_tool, disposes telemetry on shutdown.
dotnet/README.md	Documents telemetry + agent attribution options for .NET users.
docs/opentelemetry-instrumentation.md	Rewrites OTel docs to describe built-in instrumentation and configuration.
README.md	Adds top-level docs link to OpenTelemetry instrumentation guide.

Files not reviewed (1)

• nodejs/package-lock.json: Language not supported