Add rate limits to the token_usage event

pkg/chat/chat.go

@@ -114,12 +114,13 @@ type MessageStreamChoice struct {
 
 // MessageStreamResponse represents a streaming response from the model
 type MessageStreamResponse struct {
-	ID      string                `json:"id"`
-	Object  string                `json:"object"`
-	Created int64                 `json:"created"`
-	Model   string                `json:"model"`
-	Choices []MessageStreamChoice `json:"choices"`
-	Usage   *Usage                `json:"usage,omitempty"`
+	ID        string                `json:"id"`
+	Object    string                `json:"object"`
+	Created   int64                 `json:"created"`
+	Model     string                `json:"model"`
+	Choices   []MessageStreamChoice `json:"choices"`
+	Usage     *Usage                `json:"usage,omitempty"`
+	RateLimit *RateLimit            `json:"rate_limit,omitempty"`
 }
 
 type Usage struct {
@@ -130,6 +131,13 @@ type Usage struct {
 	ReasoningTokens   int64 `json:"reasoning_tokens,omitempty"`
 }
 
+type RateLimit struct {
+	Limit      int64 `json:"limit,omitempty"`
+	Remaining  int64 `json:"remaining,omitempty"`
+	Reset      int64 `json:"reset,omitempty"`
+	RetryAfter int64 `json:"retry_after,omitempty"`
+}
+
 // MessageStream interface represents a stream of chat completions
 type MessageStream interface {
 	// Recv gets the next completion chunk

pkg/model/provider/anthropic/adapter.go

@@ -6,6 +6,7 @@ import (
 	"fmt"
 	"io"
 	"net/http"
+	"strconv"
 	"strings"
 
 	"github.com/anthropics/anthropic-sdk-go"
@@ -23,14 +24,16 @@ type streamAdapter struct {
 	toolCall   bool
 	toolID     string
 	// For single retry on context length error
-	retryFn func() *streamAdapter
-	retried bool
+	retryFn            func() *streamAdapter
+	retried            bool
+	getResponseTrailer func() http.Header
 }
 
-func newStreamAdapter(stream *ssestream.Stream[anthropic.MessageStreamEventUnion], trackUsage bool) *streamAdapter {
+func (c *Client) newStreamAdapter(stream *ssestream.Stream[anthropic.MessageStreamEventUnion], trackUsage bool) *streamAdapter {
 	return &streamAdapter{
-		stream:     stream,
-		trackUsage: trackUsage,
+		stream:             stream,
+		trackUsage:         trackUsage,
+		getResponseTrailer: c.getResponseTrailer,
 	}
 }
 
@@ -163,11 +166,30 @@ func (a *streamAdapter) Recv() (chat.MessageStreamResponse, error) {
 		} else {
 			response.Choices[0].FinishReason = chat.FinishReasonStop
 		}
+
+		// MessageStopEvent is the last event. Let's drain the response to get the trailing headers.
+		trailers := a.getResponseTrailer()
+		if trailers.Get("X-RateLimit-Limit") != "" {
+			response.RateLimit = &chat.RateLimit{
+				Limit:      parseHeaderInt64(trailers.Get("X-RateLimit-Limit")),
+				Remaining:  parseHeaderInt64(trailers.Get("X-RateLimit-Remaining")),
+				Reset:      parseHeaderInt64(trailers.Get("X-RateLimit-Reset")),
+				RetryAfter: parseHeaderInt64(trailers.Get("Retry-After")),
+			}
+		}
 	}
 
 	return response, nil
 }
 
+func parseHeaderInt64(headerValue string) int64 {
+	value, err := strconv.ParseInt(headerValue, 10, 64)
+	if err != nil {
+		return 0
+	}
+	return value
+}
+
 // Close closes the stream
 func (a *streamAdapter) Close() {
 	if a.stream != nil {

pkg/model/provider/anthropic/beta_adapter.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"io"
 	"log/slog"
+	"net/http"
 
 	"github.com/anthropics/anthropic-sdk-go"
 	"github.com/anthropics/anthropic-sdk-go/packages/ssestream"
@@ -14,18 +15,22 @@ import (
 
 // betaStreamAdapter adapts the Anthropic Beta stream to our interface
 type betaStreamAdapter struct {
-	stream   *ssestream.Stream[anthropic.BetaRawMessageStreamEventUnion]
-	toolCall bool
-	toolID   string
+	stream     *ssestream.Stream[anthropic.BetaRawMessageStreamEventUnion]
+	trackUsage bool
+	toolCall   bool
+	toolID     string
 	// For single retry on context length error
-	retryFn func() *betaStreamAdapter
-	retried bool
+	retryFn            func() *betaStreamAdapter
+	retried            bool
+	getResponseTrailer func() http.Header
 }
 
 // newBetaStreamAdapter creates a new Beta stream adapter
-func newBetaStreamAdapter(stream *ssestream.Stream[anthropic.BetaRawMessageStreamEventUnion]) *betaStreamAdapter {
+func (c *Client) newBetaStreamAdapter(stream *ssestream.Stream[anthropic.BetaRawMessageStreamEventUnion], trackUsage bool) *betaStreamAdapter {
 	return &betaStreamAdapter{
-		stream: stream,
+		stream:             stream,
+		trackUsage:         trackUsage,
+		getResponseTrailer: c.getResponseTrailer,
 	}
 }
 
@@ -111,11 +116,13 @@ func (a *betaStreamAdapter) Recv() (chat.MessageStreamResponse, error) {
 			return response, fmt.Errorf("unknown delta type: %T", deltaVariant)
 		}
 	case anthropic.BetaRawMessageDeltaEvent:
-		response.Usage = &chat.Usage{
-			InputTokens:       eventVariant.Usage.InputTokens,
-			OutputTokens:      eventVariant.Usage.OutputTokens,
-			CachedInputTokens: eventVariant.Usage.CacheReadInputTokens,
-			CacheWriteTokens:  eventVariant.Usage.CacheCreationInputTokens,
+		if a.trackUsage {
+			response.Usage = &chat.Usage{
+				InputTokens:       eventVariant.Usage.InputTokens,
+				OutputTokens:      eventVariant.Usage.OutputTokens,
+				CachedInputTokens: eventVariant.Usage.CacheReadInputTokens,
+				CacheWriteTokens:  eventVariant.Usage.CacheCreationInputTokens,
+			}
 		}
 	case anthropic.BetaRawMessageStopEvent:
 		if a.toolCall {

pkg/model/provider/anthropic/beta_client.go

@@ -103,7 +103,8 @@ func (c *Client) createBetaStream(
 		"message_count", len(params.Messages))
 
 	stream := client.Beta.Messages.NewStreaming(ctx, params)
-	ad := newBetaStreamAdapter(stream)
+	trackUsage := c.ModelConfig.TrackUsage == nil || *c.ModelConfig.TrackUsage
+	ad := c.newBetaStreamAdapter(stream, trackUsage)
 
 	// Set up single retry for context length errors
 	ad.retryFn = func() *betaStreamAdapter {
@@ -120,7 +121,7 @@ func (c *Client) createBetaStream(
 		slog.Warn("Retrying with clamped max_tokens after context length error", "original", maxTokens, "clamped", newMaxTokens, "used", used)
 		retryParams := params
 		retryParams.MaxTokens = newMaxTokens
-		return newBetaStreamAdapter(client.Beta.Messages.NewStreaming(ctx, retryParams))
+		return c.newBetaStreamAdapter(client.Beta.Messages.NewStreaming(ctx, retryParams), trackUsage)
 	}
 
 	slog.Debug("Anthropic Beta API chat completion stream created successfully", "model", c.ModelConfig.Model)

pkg/model/provider/anthropic/client.go

@@ -6,7 +6,9 @@ import (
 	"encoding/json"
 	"errors"
 	"fmt"
+	"io"
 	"log/slog"
+	"net/http"
 	"net/url"
 	"strings"
 
@@ -27,7 +29,20 @@ import (
 // It holds the anthropic client and model config
 type Client struct {
 	base.Config
-	clientFn func(context.Context) (anthropic.Client, error)
+	clientFn         func(context.Context) (anthropic.Client, error)
+	lastHTTPResponse *http.Response
+}
+
+func (c *Client) getResponseTrailer() http.Header {
+	if c.lastHTTPResponse == nil {
+		return nil
+	}
+
+	if c.lastHTTPResponse.Body != nil {
+		_, _ = io.Copy(io.Discard, c.lastHTTPResponse.Body)
+	}
+
+	return c.lastHTTPResponse.Trailer
 }
 
 // adjustMaxTokensForThinking checks if max_tokens needs adjustment for thinking_budget.
@@ -116,7 +131,14 @@ func NewClient(ctx context.Context, cfg *latest.ModelConfig, env environment.Pro
 		}
 	}
 
-	var clientFn func(context.Context) (anthropic.Client, error)
+	anthropicClient := &Client{
+		Config: base.Config{
+			ModelConfig:  *cfg,
+			ModelOptions: globalOptions,
+			Env:          env,
+		},
+	}
+
 	if gateway := globalOptions.Gateway(); gateway == "" {
 		authToken, _ := env.Get(ctx, "ANTHROPIC_API_KEY")
 		if authToken == "" {
@@ -132,7 +154,7 @@ func NewClient(ctx context.Context, cfg *latest.ModelConfig, env environment.Pro
 			requestOptions = append(requestOptions, option.WithBaseURL(cfg.BaseURL))
 		}
 		client := anthropic.NewClient(requestOptions...)
-		clientFn = func(context.Context) (anthropic.Client, error) {
+		anthropicClient.clientFn = func(context.Context) (anthropic.Client, error) {
 			return client, nil
 		}
 	} else {
@@ -143,7 +165,7 @@ func NewClient(ctx context.Context, cfg *latest.ModelConfig, env environment.Pro
 		}
 
 		// When using a Gateway, tokens are short-lived.
-		clientFn = func(ctx context.Context) (anthropic.Client, error) {
+		anthropicClient.clientFn = func(ctx context.Context) (anthropic.Client, error) {
 			// Query a fresh auth token each time the client is used
 			authToken, _ := env.Get(ctx, environment.DockerDesktopTokenEnv)
 			if authToken == "" {
@@ -168,6 +190,7 @@ func NewClient(ctx context.Context, cfg *latest.ModelConfig, env environment.Pro
 			}
 
 			client := anthropic.NewClient(
+				option.WithResponseInto(&anthropicClient.lastHTTPResponse),
 				option.WithAuthToken(authToken),
 				option.WithAPIKey(authToken),
 				option.WithBaseURL(baseURL),
@@ -180,14 +203,7 @@ func NewClient(ctx context.Context, cfg *latest.ModelConfig, env environment.Pro
 
 	slog.Debug("Anthropic client created successfully", "model", cfg.Model)
 
-	return &Client{
-		Config: base.Config{
-			ModelConfig:  *cfg,
-			ModelOptions: globalOptions,
-			Env:          env,
-		},
-		clientFn: clientFn,
-	}, nil
+	return anthropicClient, nil
 }
 
 // CreateChatCompletionStream creates a streaming chat completion request
@@ -304,7 +320,7 @@ func (c *Client) CreateChatCompletionStream(
 
 	stream := client.Messages.NewStreaming(ctx, params, betaHeader)
 	trackUsage := c.ModelConfig.TrackUsage == nil || *c.ModelConfig.TrackUsage
-	ad := newStreamAdapter(stream, trackUsage)
+	ad := c.newStreamAdapter(stream, trackUsage)
 
 	// Set up single retry for context length errors
 	ad.retryFn = func() *streamAdapter {
@@ -321,7 +337,7 @@ func (c *Client) CreateChatCompletionStream(
 		slog.Warn("Retrying with clamped max_tokens after context length error", "original max_tokens", maxTokens, "clamped max_tokens", newMaxTokens, "used tokens", used)
 		retryParams := params
 		retryParams.MaxTokens = newMaxTokens
-		return newStreamAdapter(client.Messages.NewStreaming(ctx, retryParams, betaHeader), trackUsage)
+		return c.newStreamAdapter(client.Messages.NewStreaming(ctx, retryParams, betaHeader), trackUsage)
 	}
 
 	slog.Debug("Anthropic chat completion stream created successfully", "model", c.ModelConfig.Model)

pkg/runtime/event.go

@@ -208,6 +208,7 @@ type Usage struct {
 // It embeds chat.Usage and adds Cost and Model fields.
 type MessageUsage struct {
 	chat.Usage
+	chat.RateLimit
 	Cost  float64
 	Model string
 }

pkg/runtime/runtime.go

@@ -191,6 +191,7 @@ type streamResult struct {
 	Stopped           bool
 	ActualModel       string      // The actual model used (may differ from configured model with routing)
 	Usage             *chat.Usage // Token usage for this stream
+	RateLimit         *chat.RateLimit
 }
 
 type Opt func(*LocalRuntime)
@@ -946,6 +947,9 @@ func (r *LocalRuntime) RunStream(ctx context.Context, sess *session.Session) <-c
 						Model: messageModel,
 					}
 				}
+				if res.RateLimit != nil {
+					msgUsage.RateLimit = *res.RateLimit
+				}
 
 				sess.AddMessage(session.NewAgentMessage(a, &assistantMessage))
 				r.saveSession(ctx, sess)
@@ -1119,8 +1123,9 @@ func (r *LocalRuntime) handleStream(ctx context.Context, stream chat.MessageStre
 	var actualModel string
 	var actualModelEventEmitted bool
 	var messageUsage *chat.Usage
-	modelID := getAgentModelID(a)
+	var messageRateLimit *chat.RateLimit
 
+	modelID := getAgentModelID(a)
 	toolCallIndex := make(map[string]int)   // toolCallID -> index in toolCalls slice
 	emittedPartial := make(map[string]bool) // toolCallID -> whether we've emitted a partial event
 	toolDefMap := make(map[string]tools.Tool, len(agentTools))
@@ -1138,7 +1143,6 @@ func (r *LocalRuntime) handleStream(ctx context.Context, stream chat.MessageStre
 		}
 
 		if response.Usage != nil {
-			// Capture the usage for this specific message
 			messageUsage = response.Usage
 
 			if m != nil && m.Cost != nil {
@@ -1159,6 +1163,10 @@ func (r *LocalRuntime) handleStream(ctx context.Context, stream chat.MessageStre
 			telemetry.RecordTokenUsage(ctx, modelName, sess.InputTokens, sess.OutputTokens, sess.Cost)
 		}
 
+		if response.RateLimit != nil {
+			messageRateLimit = response.RateLimit
+		}
+
 		if len(response.Choices) == 0 {
 			continue
 		}
@@ -1195,6 +1203,7 @@ func (r *LocalRuntime) handleStream(ctx context.Context, stream chat.MessageStre
 				Stopped:           true,
 				ActualModel:       actualModel,
 				Usage:             messageUsage,
+				RateLimit:         messageRateLimit,
 			}, nil
 		}
 
@@ -1267,6 +1276,7 @@ func (r *LocalRuntime) handleStream(ctx context.Context, stream chat.MessageStre
 		Stopped:           stoppedDueToNoOutput,
 		ActualModel:       actualModel,
 		Usage:             messageUsage,
+		RateLimit:         messageRateLimit,
 	}, nil
 }