feat: Enhance usage tracking across response handlers

open-sse/translator/response/claude-to-openai.js

@@ -92,9 +92,34 @@ export function claudeToOpenAIResponse(chunk, state) {
     }
 
     case "message_delta": {
+      // Extract usage from message_delta event (Claude native format)
+      // Normalize to OpenAI format (prompt_tokens/completion_tokens) for consistent logging
+      if (chunk.usage && typeof chunk.usage === "object") {
+        const inputTokens = typeof chunk.usage.input_tokens === "number" ? chunk.usage.input_tokens : 0;
+        const outputTokens = typeof chunk.usage.output_tokens === "number" ? chunk.usage.output_tokens : 0;
+        const cacheReadTokens = typeof chunk.usage.cache_read_input_tokens === "number" ? chunk.usage.cache_read_input_tokens : 0;
+        const cacheCreationTokens = typeof chunk.usage.cache_creation_input_tokens === "number" ? chunk.usage.cache_creation_input_tokens : 0;
+        
+        // Use OpenAI format keys for consistent logging in stream.js
+        state.usage = {
+          prompt_tokens: inputTokens,
+          completion_tokens: outputTokens,
+          input_tokens: inputTokens,
+          output_tokens: outputTokens
+        };
+        
+        // Store cache tokens if present
+        if (cacheReadTokens > 0) {
+          state.usage.cache_read_input_tokens = cacheReadTokens;
+        }
+        if (cacheCreationTokens > 0) {
+          state.usage.cache_creation_input_tokens = cacheCreationTokens;
+        }
+      }
+      
       if (chunk.delta?.stop_reason) {
         state.finishReason = convertStopReason(chunk.delta.stop_reason);
-        results.push({
+        const finalChunk = {
           id: `chatcmpl-${state.messageId}`,
           object: "chat.completion.chunk",
           created: Math.floor(Date.now() / 1000),
@@ -104,7 +129,41 @@ export function claudeToOpenAIResponse(chunk, state) {
             delta: {},
             finish_reason: state.finishReason
           }]
-        });
+        };
+        
+        // Include usage in final chunk if available
+        if (state.usage && typeof state.usage === "object") {
+          const inputTokens = state.usage.input_tokens || 0;
+          const outputTokens = state.usage.output_tokens || 0;
+          const cachedTokens = state.usage.cache_read_input_tokens || 0;
+          const cacheCreationTokens = state.usage.cache_creation_input_tokens || 0;
+          
+          // prompt_tokens = input_tokens + cache_read + cache_creation (all prompt-side tokens)
+          // completion_tokens = output_tokens
+          // total_tokens = prompt_tokens + completion_tokens
+          const promptTokens = inputTokens + cachedTokens + cacheCreationTokens;
+          const completionTokens = outputTokens;
+          const totalTokens = promptTokens + completionTokens;
+          
+          finalChunk.usage = {
+            prompt_tokens: promptTokens,
+            completion_tokens: completionTokens,
+            total_tokens: totalTokens
+          };
+          
+          // Add prompt_tokens_details if cached tokens exist
+          if (cachedTokens > 0 || cacheCreationTokens > 0) {
+            finalChunk.usage.prompt_tokens_details = {};
+            if (cachedTokens > 0) {
+              finalChunk.usage.prompt_tokens_details.cached_tokens = cachedTokens;
+            }
+            if (cacheCreationTokens > 0) {
+              finalChunk.usage.prompt_tokens_details.cache_creation_tokens = cacheCreationTokens;
+            }
+          }
+        }
+        
+        results.push(finalChunk);
         state.finishReasonSent = true;
       }
       break;