coder · pawbana · Dec 5, 2025 · Nov 19, 2025 · Nov 25, 2025 · Nov 26, 2025
diff --git a/bridge.go b/bridge.go
@@ -9,6 +9,7 @@ import (
 
 	"cdr.dev/slog"
 	"github.com/coder/aibridge/mcp"
+	"go.opentelemetry.io/otel/trace"
 
 	"github.com/hashicorp/go-multierror"
 )
@@ -47,20 +48,20 @@ var _ http.Handler = &RequestBridge{}
 // A [Recorder] is also required to record prompt, tool, and token use.
 //
 // mcpProxy will be closed when the [RequestBridge] is closed.
-func NewRequestBridge(ctx context.Context, providers []Provider, recorder Recorder, mcpProxy mcp.ServerProxier, metrics *Metrics, logger slog.Logger) (*RequestBridge, error) {
+func NewRequestBridge(ctx context.Context, providers []Provider, recorder Recorder, mcpProxy mcp.ServerProxier, logger slog.Logger, metrics *Metrics, tracer trace.Tracer) (*RequestBridge, error) {
 	mux := http.NewServeMux()
 
 	for _, provider := range providers {
 		// Add the known provider-specific routes which are bridged (i.e. intercepted and augmented).
 		for _, path := range provider.BridgedRoutes() {
-			mux.HandleFunc(path, newInterceptionProcessor(provider, logger, recorder, mcpProxy, metrics))
+			mux.HandleFunc(path, newInterceptionProcessor(provider, recorder, mcpProxy, logger, metrics, tracer))
 		}
 
 		// Any requests which passthrough to this will be reverse-proxied to the upstream.
 		//
 		// We have to whitelist the known-safe routes because an API key with elevated privileges (i.e. admin) might be
 		// configured, so we should just reverse-proxy known-safe routes.
-		ftr := newPassthroughRouter(provider, logger.Named(fmt.Sprintf("passthrough.%s", provider.Name())), metrics)
+		ftr := newPassthroughRouter(provider, logger.Named(fmt.Sprintf("passthrough.%s", provider.Name())), metrics, tracer)
 		for _, path := range provider.PassthroughRoutes() {
 			prefix := fmt.Sprintf("/%s", provider.Name())
 			route := fmt.Sprintf("%s%s", prefix, path)

diff --git a/bridge_integration_test.go b/bridge_integration_test.go
diff --git a/go.mod b/go.mod
@@ -26,6 +26,13 @@ require (
 	github.com/openai/openai-go/v2 v2.7.0
 )
 
+// Tracing-related libs.
+require (
-require (
+// Tracing-related libs.
+require (
-require (
+// Tracing-related libs.
+require (
+	go.opentelemetry.io/otel v1.38.0
+	go.opentelemetry.io/otel/sdk v1.38.0
+	go.opentelemetry.io/otel/trace v1.38.0
+)
+
 require (
 	github.com/aws/aws-sdk-go-v2 v1.30.3 // indirect
 	github.com/aws/aws-sdk-go-v2/aws/protocol/eventstream v1.6.3 // indirect
@@ -46,6 +53,8 @@ require (
 	github.com/cespare/xxhash/v2 v2.3.0 // indirect
 	github.com/charmbracelet/lipgloss v0.7.1 // indirect
 	github.com/davecgh/go-spew v1.1.2-0.20180830191138-d8f796af33cc // indirect
+	github.com/go-logr/logr v1.4.3 // indirect
+	github.com/go-logr/stdr v1.2.2 // indirect
 	github.com/hashicorp/errwrap v1.0.0 // indirect
 	github.com/invopop/jsonschema v0.13.0 // indirect
 	github.com/kylelemons/godebug v1.1.0 // indirect
@@ -61,14 +70,13 @@ require (
 	github.com/prometheus/common v0.66.1 // indirect
 	github.com/prometheus/procfs v0.16.1 // indirect
 	github.com/rivo/uniseg v0.4.4 // indirect
-	github.com/rogpeppe/go-internal v1.13.1 // indirect
 	github.com/spf13/cast v1.7.1 // indirect
 	github.com/tidwall/match v1.2.0 // indirect
 	github.com/tidwall/pretty v1.2.1 // indirect
 	github.com/wk8/go-ordered-map/v2 v2.1.8 // indirect
 	github.com/yosida95/uritemplate/v3 v3.0.2 // indirect
-	go.opentelemetry.io/otel v1.33.0 // indirect
-	go.opentelemetry.io/otel/trace v1.33.0 // indirect
+	go.opentelemetry.io/auto/sdk v1.1.0 // indirect
+	go.opentelemetry.io/otel/metric v1.38.0 // indirect
 	go.yaml.in/yaml/v2 v2.4.2 // indirect
 	golang.org/x/sys v0.35.0 // indirect
 	golang.org/x/term v0.34.0 // indirect

diff --git a/go.sum b/go.sum
@@ -53,8 +53,9 @@ github.com/davecgh/go-spew v1.1.2-0.20180830191138-d8f796af33cc h1:U9qPSI2PIWSS1
 github.com/davecgh/go-spew v1.1.2-0.20180830191138-d8f796af33cc/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/frankban/quicktest v1.14.6 h1:7Xjx+VpznH+oBnejlPUj8oUpdxnVs4f8XU8WnHkI4W8=
 github.com/frankban/quicktest v1.14.6/go.mod h1:4ptaffx2x8+WTWXmUCuVU6aPUX1/Mz7zb5vbUoiM6w0=
-github.com/go-logr/logr v1.4.2 h1:6pFjapn8bFcIbiKo3XT4j/BhANplGihG6tvd+8rYgrY=
-github.com/go-logr/logr v1.4.2/go.mod h1:9T104GzyrTigFIr8wt5mBrctHMim0Nb2HLGrmQ40KvY=
+github.com/go-logr/logr v1.2.2/go.mod h1:jdQByPbusPIv2/zmleS9BjJVeZ6kBagPoEUsqbVz/1A=
+github.com/go-logr/logr v1.4.3 h1:CjnDlHq8ikf6E492q6eKboGOC0T8CDaOvkHCIg8idEI=
+github.com/go-logr/logr v1.4.3/go.mod h1:9T104GzyrTigFIr8wt5mBrctHMim0Nb2HLGrmQ40KvY=
 github.com/go-logr/stdr v1.2.2 h1:hSWxHoqTgW2S2qGc0LTAI563KZ5YKYRhT3MFKZMbjag=
 github.com/go-logr/stdr v1.2.2/go.mod h1:mMo/vtBO5dYbehREoey6XUKy/eSumjCCveDpRre4VKE=
 github.com/google/go-cmp v0.7.0 h1:wk8382ETsv4JYUZwIsn6YpYiWiBsYLSJiTsyBybVuN8=
@@ -130,14 +131,16 @@ github.com/yosida95/uritemplate/v3 v3.0.2 h1:Ed3Oyj9yrmi9087+NczuL5BwkIc4wvTb5zI
 github.com/yosida95/uritemplate/v3 v3.0.2/go.mod h1:ILOh0sOhIJR3+L/8afwt/kE++YT040gmv5BQTMR2HP4=
 go.opentelemetry.io/auto/sdk v1.1.0 h1:cH53jehLUN6UFLY71z+NDOiNJqDdPRaXzTel0sJySYA=
 go.opentelemetry.io/auto/sdk v1.1.0/go.mod h1:3wSPjt5PWp2RhlCcmmOial7AvC4DQqZb7a7wCow3W8A=
-go.opentelemetry.io/otel v1.33.0 h1:/FerN9bax5LoK51X/sI0SVYrjSE0/yUL7DpxW4K3FWw=
-go.opentelemetry.io/otel v1.33.0/go.mod h1:SUUkR6csvUQl+yjReHu5uM3EtVV7MBm5FHKRlNx4I8I=
-go.opentelemetry.io/otel/metric v1.33.0 h1:r+JOocAyeRVXD8lZpjdQjzMadVZp2M4WmQ+5WtEnklQ=
-go.opentelemetry.io/otel/metric v1.33.0/go.mod h1:L9+Fyctbp6HFTddIxClbQkjtubW6O9QS3Ann/M82u6M=
-go.opentelemetry.io/otel/sdk v1.16.0 h1:Z1Ok1YsijYL0CSJpHt4cS3wDDh7p572grzNrBMiMWgE=
-go.opentelemetry.io/otel/sdk v1.16.0/go.mod h1:tMsIuKXuuIWPBAOrH+eHtvhTL+SntFtXF9QD68aP6p4=
-go.opentelemetry.io/otel/trace v1.33.0 h1:cCJuF7LRjUFso9LPnEAHJDB2pqzp+hbO8eu1qqW2d/s=
-go.opentelemetry.io/otel/trace v1.33.0/go.mod h1:uIcdVUZMpTAmz0tI1z04GoVSezK37CbGV4fr1f2nBck=
+go.opentelemetry.io/otel v1.38.0 h1:RkfdswUDRimDg0m2Az18RKOsnI8UDzppJAtj01/Ymk8=
+go.opentelemetry.io/otel v1.38.0/go.mod h1:zcmtmQ1+YmQM9wrNsTGV/q/uyusom3P8RxwExxkZhjM=
+go.opentelemetry.io/otel/metric v1.38.0 h1:Kl6lzIYGAh5M159u9NgiRkmoMKjvbsKtYRwgfrA6WpA=
+go.opentelemetry.io/otel/metric v1.38.0/go.mod h1:kB5n/QoRM8YwmUahxvI3bO34eVtQf2i4utNVLr9gEmI=
+go.opentelemetry.io/otel/sdk v1.38.0 h1:l48sr5YbNf2hpCUj/FoGhW9yDkl+Ma+LrVl8qaM5b+E=
+go.opentelemetry.io/otel/sdk v1.38.0/go.mod h1:ghmNdGlVemJI3+ZB5iDEuk4bWA3GkTpW+DOoZMYBVVg=
+go.opentelemetry.io/otel/sdk/metric v1.38.0 h1:aSH66iL0aZqo//xXzQLYozmWrXxyFkBJ6qT5wthqPoM=
+go.opentelemetry.io/otel/sdk/metric v1.38.0/go.mod h1:dg9PBnW9XdQ1Hd6ZnRz689CbtrUp0wMMs9iPcgT9EZA=
+go.opentelemetry.io/otel/trace v1.38.0 h1:Fxk5bKrDZJUH+AMyyIXGcFAPah0oRcT+LuNtJrmcNLE=
+go.opentelemetry.io/otel/trace v1.38.0/go.mod h1:j1P9ivuFsTceSWe1oY+EeW3sc+Pp42sO++GHkg4wwhs=
 go.uber.org/goleak v1.3.0 h1:2K3zAYmnTNqV73imy9J1T3WC+gmCePx2hEGkimedGto=
 go.uber.org/goleak v1.3.0/go.mod h1:CoHD4mav9JJNrW/WLlf7HGZPjdw8EucARQHekz1X6bE=
 go.uber.org/mock v0.6.0 h1:hyF9dfmbgIX5EfOdasqLsWD6xqpNZlXblLB/Dbnwv3Y=

diff --git a/intercept_anthropic_messages_base.go b/intercept_anthropic_messages_base.go
@@ -15,7 +15,10 @@ import (
 	"github.com/aws/aws-sdk-go-v2/config"
 	"github.com/aws/aws-sdk-go-v2/credentials"
 	"github.com/coder/aibridge/mcp"
+	"github.com/coder/aibridge/tracing"
 	"github.com/google/uuid"
+	"go.opentelemetry.io/otel/attribute"
+	"go.opentelemetry.io/otel/trace"
 
 	"cdr.dev/slog"
 )
@@ -27,6 +30,7 @@ type AnthropicMessagesInterceptionBase struct {
 	cfg        AnthropicConfig
 	bedrockCfg *AWSBedrockConfig
 
+	tracer trace.Tracer
 	logger slog.Logger
 
 	recorder Recorder
@@ -59,6 +63,18 @@ func (i *AnthropicMessagesInterceptionBase) Model() string {
 	return string(i.req.Model)
 }
 
+func (s *AnthropicMessagesInterceptionBase) baseTraceAttributes(r *http.Request, streaming bool) []attribute.KeyValue {
+	return []attribute.KeyValue{
+		attribute.String(tracing.RequestPath, r.URL.Path),
+		attribute.String(tracing.InterceptionID, s.id.String()),
+		attribute.String(tracing.InitiatorID, actorFromContext(r.Context()).id),
+		attribute.String(tracing.Provider, ProviderAnthropic),
+		attribute.String(tracing.Model, s.Model()),
+		attribute.Bool(tracing.Streaming, streaming),
+		attribute.Bool(tracing.IsBedrock, s.bedrockCfg != nil),
+	}
+}
+
 func (i *AnthropicMessagesInterceptionBase) injectTools() {
 	if i.req == nil || i.mcpProxy == nil {
 		return

diff --git a/intercept_anthropic_messages_blocking.go b/intercept_anthropic_messages_blocking.go
@@ -1,6 +1,7 @@
 package aibridge
 
 import (
+	"context"
 	"fmt"
 	"net/http"
 	"time"
@@ -10,8 +11,11 @@ import (
 	"github.com/google/uuid"
 	mcplib "github.com/mark3labs/mcp-go/mcp" // TODO: abstract this away so callers need no knowledge of underlying lib.
 	"github.com/tidwall/sjson"
+	"go.opentelemetry.io/otel/attribute"
+	"go.opentelemetry.io/otel/trace"
 
 	"github.com/coder/aibridge/mcp"
+	"github.com/coder/aibridge/tracing"
 
 	"cdr.dev/slog"
 )
@@ -22,29 +26,35 @@ type AnthropicMessagesBlockingInterception struct {
 	AnthropicMessagesInterceptionBase
 }
 
-func NewAnthropicMessagesBlockingInterception(id uuid.UUID, req *MessageNewParamsWrapper, cfg AnthropicConfig, bedrockCfg *AWSBedrockConfig) *AnthropicMessagesBlockingInterception {
+func NewAnthropicMessagesBlockingInterception(id uuid.UUID, req *MessageNewParamsWrapper, cfg AnthropicConfig, bedrockCfg *AWSBedrockConfig, tracer trace.Tracer) *AnthropicMessagesBlockingInterception {
 	return &AnthropicMessagesBlockingInterception{AnthropicMessagesInterceptionBase: AnthropicMessagesInterceptionBase{
 		id:         id,
 		req:        req,
 		cfg:        cfg,
 		bedrockCfg: bedrockCfg,
+		tracer:     tracer,
 	}}
 }
 
-func (s *AnthropicMessagesBlockingInterception) Setup(logger slog.Logger, recorder Recorder, mcpProxy mcp.ServerProxier) {
-	s.AnthropicMessagesInterceptionBase.Setup(logger.Named("blocking"), recorder, mcpProxy)
+func (i *AnthropicMessagesBlockingInterception) Setup(logger slog.Logger, recorder Recorder, mcpProxy mcp.ServerProxier) {
+	i.AnthropicMessagesInterceptionBase.Setup(logger.Named("blocking"), recorder, mcpProxy)
+}
+
+func (i *AnthropicMessagesBlockingInterception) TraceAttributes(r *http.Request) []attribute.KeyValue {
+	return i.AnthropicMessagesInterceptionBase.baseTraceAttributes(r, false)
 }
 
 func (s *AnthropicMessagesBlockingInterception) Streaming() bool {
 	return false
 }
 
-func (i *AnthropicMessagesBlockingInterception) ProcessRequest(w http.ResponseWriter, r *http.Request) error {
+func (i *AnthropicMessagesBlockingInterception) ProcessRequest(w http.ResponseWriter, r *http.Request) (outErr error) {
 	if i.req == nil {
 		return fmt.Errorf("developer error: req is nil")
 	}
 
-	ctx := r.Context()
+	ctx, span := i.tracer.Start(r.Context(), "Intercept.ProcessRequest", trace.WithAttributes(tracing.InterceptionAttributesFromContext(r.Context())...))
+	defer tracing.EndSpanErr(span, &outErr)
 
 	i.injectTools()
 
@@ -77,7 +87,8 @@ func (i *AnthropicMessagesBlockingInterception) ProcessRequest(w http.ResponseWr
 	var cumulativeUsage anthropic.Usage
 
 	for {
-		resp, err = svc.New(ctx, messages)
+		// TODO add outer loop span (https://github.com/coder/aibridge/issues/67)
+		resp, err = i.newMessage(ctx, svc, messages)
 		if err != nil {
 			if isConnError(err) {
 				// Can't write a response, just error out.
@@ -166,7 +177,7 @@ func (i *AnthropicMessagesBlockingInterception) ProcessRequest(w http.ResponseWr
 				continue
 			}
 
-			res, err := tool.Call(ctx, tc.Input)
+			res, err := tool.Call(ctx, tc.Input, i.tracer)
 
 			_ = i.recorder.RecordToolUsage(ctx, &ToolUsageRecord{
 				InterceptionID:  i.ID().String(),
@@ -286,3 +297,10 @@ func (i *AnthropicMessagesBlockingInterception) ProcessRequest(w http.ResponseWr
 
 	return nil
 }
+
+func (i *AnthropicMessagesBlockingInterception) newMessage(ctx context.Context, svc anthropic.MessageService, msgParams anthropic.MessageNewParams) (_ *anthropic.Message, outErr error) {
+	ctx, span := i.tracer.Start(ctx, "Intercept.ProcessRequest.Upstream", trace.WithAttributes(tracing.InterceptionAttributesFromContext(ctx)...))
+	defer tracing.EndSpanErr(span, &outErr)
+
+	return svc.New(ctx, msgParams)
+}
diff --git a/intercept_anthropic_messages_streaming.go b/intercept_anthropic_messages_streaming.go
@@ -11,11 +11,15 @@ import (
 	"time"
 
 	"github.com/anthropics/anthropic-sdk-go"
+	"github.com/anthropics/anthropic-sdk-go/packages/ssestream"
 	"github.com/anthropics/anthropic-sdk-go/shared/constant"
 	"github.com/coder/aibridge/mcp"
+	"github.com/coder/aibridge/tracing"
 	"github.com/google/uuid"
 	mcplib "github.com/mark3labs/mcp-go/mcp"
 	"github.com/tidwall/sjson"
+	"go.opentelemetry.io/otel/attribute"
+	"go.opentelemetry.io/otel/trace"
 
 	"cdr.dev/slog"
 )
@@ -26,12 +30,13 @@ type AnthropicMessagesStreamingInterception struct {
 	AnthropicMessagesInterceptionBase
 }
 
-func NewAnthropicMessagesStreamingInterception(id uuid.UUID, req *MessageNewParamsWrapper, cfg AnthropicConfig, bedrockCfg *AWSBedrockConfig) *AnthropicMessagesStreamingInterception {
+func NewAnthropicMessagesStreamingInterception(id uuid.UUID, req *MessageNewParamsWrapper, cfg AnthropicConfig, bedrockCfg *AWSBedrockConfig, tracer trace.Tracer) *AnthropicMessagesStreamingInterception {
 	return &AnthropicMessagesStreamingInterception{AnthropicMessagesInterceptionBase: AnthropicMessagesInterceptionBase{
 		id:         id,
 		req:        req,
 		cfg:        cfg,
 		bedrockCfg: bedrockCfg,
+		tracer:     tracer,
 	}}
 }
 
@@ -43,6 +48,10 @@ func (s *AnthropicMessagesStreamingInterception) Streaming() bool {
 	return true
 }
 
+func (s *AnthropicMessagesStreamingInterception) TraceAttributes(r *http.Request) []attribute.KeyValue {
+	return s.AnthropicMessagesInterceptionBase.baseTraceAttributes(r, true)
+}
+
 // ProcessRequest handles a request to /v1/messages.
 // This API has a state-machine behind it, which is described in https://docs.claude.com/en/docs/build-with-claude/streaming#event-types.
 //
@@ -62,13 +71,16 @@ func (s *AnthropicMessagesStreamingInterception) Streaming() bool {
 // b) if the tool is injected, it will be invoked by the [mcp.ServerProxier] in the remote MCP server, and its
 // results relayed to the SERVER. The response from the server will be handled synchronously, and this loop
 // can continue until all injected tool invocations are completed and the response is relayed to the client.
-func (i *AnthropicMessagesStreamingInterception) ProcessRequest(w http.ResponseWriter, r *http.Request) error {
+func (i *AnthropicMessagesStreamingInterception) ProcessRequest(w http.ResponseWriter, r *http.Request) (outErr error) {
 	if i.req == nil {
 		return fmt.Errorf("developer error: req is nil")
 	}
 
+	ctx, span := i.tracer.Start(r.Context(), "Intercept.ProcessRequest", trace.WithAttributes(tracing.InterceptionAttributesFromContext(r.Context())...))
+	defer tracing.EndSpanErr(span, &outErr)
+
 	// Allow us to interrupt watch via cancel.
-	ctx, cancel := context.WithCancel(r.Context())
+	ctx, cancel := context.WithCancel(ctx)
 	defer cancel()
 	r = r.WithContext(ctx) // Rewire context for SSE cancellation.
 
@@ -118,12 +130,13 @@ func (i *AnthropicMessagesStreamingInterception) ProcessRequest(w http.ResponseW
 	isFirst := true
 newStream:
 	for {
+		// TODO add outer loop span (https://github.com/coder/aibridge/issues/67)
 		if err := streamCtx.Err(); err != nil {
 			lastErr = fmt.Errorf("stream exit: %w", err)
 			break
 		}
 
-		stream := svc.NewStreaming(streamCtx, messages)
+		stream := i.newStream(streamCtx, svc, messages)
 
 		var message anthropic.Message
 		var lastToolName string
@@ -270,7 +283,7 @@ newStream:
 							continue
 						}
 
-						res, err := tool.Call(streamCtx, input)
+						res, err := tool.Call(streamCtx, input, i.tracer)
 
 						_ = i.recorder.RecordToolUsage(streamCtx, &ToolUsageRecord{
 							InterceptionID:  i.ID().String(),
@@ -522,3 +535,11 @@ func (s *AnthropicMessagesStreamingInterception) encodeForStream(payload []byte,
 	buf.WriteString("\n\n")
 	return buf.Bytes()
 }
+
+// newStream traces svc.NewStreaming(streamCtx, messages)
+func (s *AnthropicMessagesStreamingInterception) newStream(ctx context.Context, svc anthropic.MessageService, messages anthropic.MessageNewParams) *ssestream.Stream[anthropic.MessageStreamEventUnion] {
+	_, span := s.tracer.Start(ctx, "Intercept.ProcessRequest.Upstream", trace.WithAttributes(tracing.InterceptionAttributesFromContext(ctx)...))
+	defer span.End()
+
+	return svc.NewStreaming(ctx, messages)
+}
diff --git a/intercept_openai_chat_base.go b/intercept_openai_chat_base.go
@@ -7,20 +7,25 @@ import (
 	"strings"
 
 	"github.com/coder/aibridge/mcp"
+	"github.com/coder/aibridge/tracing"
 	"github.com/google/uuid"
 	"github.com/openai/openai-go/v2"
 	"github.com/openai/openai-go/v2/option"
 	"github.com/openai/openai-go/v2/shared"
+	"go.opentelemetry.io/otel/attribute"
+	"go.opentelemetry.io/otel/trace"
 
 	"cdr.dev/slog"
 )
 
 type OpenAIChatInterceptionBase struct {
-	id  uuid.UUID
-	req *ChatCompletionNewParamsWrapper
+	id      uuid.UUID
+	req     *ChatCompletionNewParamsWrapper
+	baseURL string
+	key     string
 
-	baseURL, key string
-	logger       slog.Logger
+	logger slog.Logger
+	tracer trace.Tracer
 
 	recorder Recorder
 	mcpProxy mcp.ServerProxier
@@ -42,6 +47,17 @@ func (i *OpenAIChatInterceptionBase) Setup(logger slog.Logger, recorder Recorder
 	i.mcpProxy = mcpProxy
 }
 
+func (s *OpenAIChatInterceptionBase) baseTraceAttributes(r *http.Request, streaming bool) []attribute.KeyValue {
+	return []attribute.KeyValue{
+		attribute.String(tracing.RequestPath, r.URL.Path),
+		attribute.String(tracing.InterceptionID, s.id.String()),
+		attribute.String(tracing.InitiatorID, actorFromContext(r.Context()).id),
+		attribute.String(tracing.Provider, ProviderOpenAI),
+		attribute.String(tracing.Model, s.Model()),
+		attribute.Bool(tracing.Streaming, streaming),
+	}
+}
+
 func (i *OpenAIChatInterceptionBase) Model() string {
 	if i.req == nil {
 		return "coder-aibridge-unknown"