diff --git a/docs/dev/tracing.md b/docs/dev/tracing.md
index ba09a08..e6fe6c6 100644
--- a/docs/dev/tracing.md
+++ b/docs/dev/tracing.md
@@ -3,9 +3,9 @@ title: "Tracing"
 summary: Turn on OpenTelemetry tracing, view traces in the dashboard and export them.
 audience: dev
 order: 80
-status: migrated
 covers:
   - shared/utils/tracing/**
+  - server/proxy_routes.py
 ---
 
 # OpenTelemetry Distributed Tracing
@@ -21,24 +21,31 @@ MATE uses OpenTelemetry for distributed tracing of agent executions, LLM calls,
 OTEL_TRACING_ENABLED=true
 
 # Optional: OTLP endpoint for Jaeger, Grafana Tempo, Datadog, Honeycomb (OTLP over HTTP)
-# When unset, only DB export runs (for dashboard)
+# There is no default: when unset, spans only go to the database
 OTEL_EXPORTER_OTLP_ENDPOINT=http://localhost:4318
 
-# Service name for traces
+# Service name for traces (only applies when MATE initializes its own TracerProvider)
 OTEL_SERVICE_NAME=mate
 
 # Store spans in database for dashboard viewer (default: true when tracing enabled)
 OTEL_TRACES_DB_EXPORT=true
 ```
 
-### Zero Performance When Disabled
+### Performance When Disabled
 
-When `OTEL_TRACING_ENABLED=false` (default), tracing is completely disabled. No overhead is incurred.
+When `OTEL_TRACING_ENABLED=false` (default), tracing is disabled. Tool wrapping is skipped, but calls via `trace_context` still route through a no-op tracer.
+
+## Architecture & Tracer Providers
+
+- **TracerProvider integration**: When ADK has already initialized an SDK `TracerProvider`, MATE adds only its `BatchSpanProcessor(DatabaseSpanExporter())` to it and returns. In this case, MATE's OTLP exporter and `OTEL_SERVICE_NAME` configuration do not apply.
+- **Standalone TracerProvider**: When no SDK provider is found, MATE initializes its own `TracerProvider` with `service.name` set to `OTEL_SERVICE_NAME`.
+- **Database Span Exporter**: When `OTEL_TRACES_DB_EXPORT=true`, spans are batched (1-second flush delay) and persisted to the `trace_spans` table for visualization in the dashboard.
+- **OTLP Exporter**: When `OTEL_EXPORTER_OTLP_ENDPOINT` is explicitly set, spans are exported using OTLP over HTTP (`opentelemetry.exporter.otlp.proto.http`). gRPC is not supported, and `OTEL_EXPORTER_OTLP_PROTOCOL` is not read.
 
 ## Instrumentation
 
 | Instrumentation Point | Span Name | Attributes |
-|----------------------|-----------|------------|
+|---|---|---|
 | LLM inference | `gen_ai.inference` | `gen_ai.operation.name`, `gen_ai.provider.name`, `gen_ai.request.model`, `gen_ai.usage.input_tokens`, `gen_ai.usage.output_tokens` |
 | RBAC check | `mate.rbac_check` | `mate.agent.name`, `mate.user.id`, `mate.rbac.allowed` |
 | Tool invocation | `mate.tool` | `mate.tool.name`, `mate.agent.name` |
@@ -53,11 +60,9 @@ The `/dashboard/traces` page shows traces from the database when `OTEL_TRACES_DB
 
 To export to Jaeger, Grafana Tempo, Datadog, or Honeycomb:
 
-1. Run an OTLP-compatible collector (e.g. Jaeger all-in-one, Grafana OTLP collector)
-2. Set `OTEL_EXPORTER_OTLP_ENDPOINT` to the collector's OTLP HTTP URL, for example
-   `http://localhost:4318`. There is no default: without it, spans only go to the
-   database. The exporter is OTLP over HTTP; gRPC is not supported.
+1. Run an OTLP-compatible collector (e.g. Jaeger all-in-one, Grafana OTLP collector).
+2. Set `OTEL_EXPORTER_OTLP_ENDPOINT` to the collector's OTLP HTTP URL (for example `http://localhost:4318`). There is no default: without this variable, spans only go to the database. Only OTLP over HTTP is supported (`opentelemetry.exporter.otlp.proto.http`). gRPC is not supported, and `OTEL_EXPORTER_OTLP_PROTOCOL` is ignored.
 
 ## W3C Trace Context
 
-Trace context is propagated via `traceparent` and `tracestate` headers. The auth server proxy forwards requests to ADK with trace context injected when tracing is enabled.
+Trace context is injected by the auth server proxy (`_inject_trace_headers` in `server/proxy_routes.py`) when forwarding requests to ADK if tracing is enabled. Nothing extracts trace context from inbound external requests.