fix(kiro): report real output tokens and stop discarding usable turns

open-sse/executors/kiro.js

@@ -144,6 +144,12 @@ function normalizeStopReason(value) {
   return reason || null;
 }
 
+// Of the reasons stopDisposition() folds into "terminal_incomplete", only these
+// mean "usable as far as it got, then the budget ran out" -- the case
+// finish_reason "length" exists for. cancelled / pause_turn are abandoned turns
+// whose partial content must stay private, so they are deliberately absent.
+const KIRO_TRUNCATION_STOP_REASONS = new Set(["model_context_window_exceeded", "max_tokens"]);
+
 function stopDisposition(stopReason, hasToolCalls) {
   if (["malformed_model_output", "invalid_model_output"].includes(stopReason)) return "retryable_protocol_failure";
   if (["cancelled", "pause_turn", "model_context_window_exceeded"].includes(stopReason)) return "terminal_incomplete";
@@ -711,14 +717,25 @@ export class KiroExecutor extends BaseExecutor {
     };
     const emitTools = (controller) => {
       for (const tool of state.tools.values()) {
-        const input = parsedToolInput(tool);
-        if (tool.name === "tool_call") {
-          if (typeof input.name !== "string" || !input.name.trim()) {
-            throw new Error("Invalid Kiro tool_call payload: missing nested MCP tool name");
-          }
-          if (!Object.prototype.hasOwnProperty.call(input, "arguments")) {
-            throw new Error("Invalid Kiro tool_call payload: missing nested MCP tool arguments");
+        // Validate per tool, not per turn: one unusable fragment used to throw out
+        // of emitTools and take every other complete tool call in the same turn
+        // with it, which the client saw as a turn that answered nothing.
+        let input;
+        try {
+          input = parsedToolInput(tool);
+          if (tool.name === "tool_call") {
+            if (typeof input.name !== "string" || !input.name.trim()) {
+              throw new Error("Invalid Kiro tool_call payload: missing nested MCP tool name");
+            }
+            if (!Object.prototype.hasOwnProperty.call(input, "arguments")) {
+              throw new Error("Invalid Kiro tool_call payload: missing nested MCP tool arguments");
+            }
           }
+        } catch (error) {
+          state.droppedTools = (state.droppedTools || 0) + 1;
+          state.toolValidationError ||= error.message;
+          console.error(`[Kiro] dropping unusable tool call ${tool.id} (${tool.name}): ${error.message}`);
+          continue;
         }
         const index = state.toolCounter++;
         emitDelta(controller, {
@@ -729,14 +746,26 @@ export class KiroExecutor extends BaseExecutor {
             function: { name: tool.name, arguments: "" }
           }]
         });
+        const serializedInput = JSON.stringify(input);
         emitDelta(controller, {
-          tool_calls: [{ index, function: { arguments: JSON.stringify(input) } }]
+          tool_calls: [{ index, function: { arguments: serializedInput } }]
         });
+        // Tool arguments are billed output like any other completion bytes. They
+        // were never added to totalContentLength, so the /4 estimator in finish()
+        // reported OUT 0 -- or the Math.max floor of 1 -- for every turn whose
+        // entire answer was a tool call.
+        state.totalContentLength += tool.name.length + serializedInput.length;
         state.hasToolCalls = true;
       }
       state.tools.clear();
       state.bufferedToolBytes = 0;
-      if (state.stopReason === "tool_use" && !state.hasToolCalls) {
+      // A declared tool turn that emitted no usable call is only fatal when the
+      // turn produced nothing else. Throwing unconditionally here escaped
+      // emitTools() with provenance "invalid_tool_call", which the integrity gate
+      // re-derived into a repair retry -- discarding text the client had already
+      // been promised.
+      if (state.stopReason === "tool_use" && !state.hasToolCalls &&
+          !state.hasText && !state.hasReasoning && !state.hasCode) {
         throw new Error("Kiro tool_use stop reason did not include a complete tool call");
       }
     };
@@ -796,7 +825,6 @@ export class KiroExecutor extends BaseExecutor {
         emitDelta(controller, { content: event.payload.content });
       } else if (eventType === "toolUseEvent") {
         state.sawToolUse = true;
-        if (state.toolValidationError) return true;
         const values = Array.isArray(event.payload) ? event.payload : [event.payload];
         if (!values[0]) throw new Error("Kiro toolUseEvent is empty");
         for (const value of values) {
@@ -924,9 +952,10 @@ export class KiroExecutor extends BaseExecutor {
         } catch (error) {
           const bufferExceeded = error.code === "KIRO_BUFFER_EXCEEDED";
           if (!bufferExceeded) {
+            // Keep whatever is already buffered: the rejected fragment belongs to
+            // one tool, and clearing the map dropped the complete calls too.
             state.toolValidationError ||= error.message;
-            state.tools.clear();
-            state.bufferedToolBytes = 0;
+            console.error(`[Kiro] tool fragment rejected, keeping ${state.tools.size} buffered tool(s): ${error.message}`);
             continue;
           }
           fail(
@@ -958,7 +987,16 @@ export class KiroExecutor extends BaseExecutor {
       }
       state.transportState = "clean_eof";
       const declaredDisposition = stopDisposition(state.stopReason, state.sawToolUse);
-      if (["retryable_protocol_failure", "terminal_incomplete", "terminal_refusal", "unknown_failure"].includes(declaredDisposition)) {
+      // model_context_window_exceeded / max_tokens map to terminal_incomplete. When
+      // they arrive after the model already streamed content, fail() threw away a
+      // complete-enough answer; a truncated turn is what finish_reason "length" is
+      // for. chunkIndex > 0 means at least one delta already reached the client.
+      const declaredTruncatedAfterOutput = declaredDisposition === "terminal_incomplete" &&
+        KIRO_TRUNCATION_STOP_REASONS.has(state.stopReason) && state.chunkIndex > 0;
+      if (declaredTruncatedAfterOutput) {
+        console.error(`[Kiro] truncated after ${state.chunkIndex} chunk(s) (stop_reason=${state.stopReason}); keeping output`);
+      }
+      if (!declaredTruncatedAfterOutput && ["retryable_protocol_failure", "terminal_incomplete", "terminal_refusal", "unknown_failure"].includes(declaredDisposition)) {
         const code = declaredDisposition === "retryable_protocol_failure"
           ? "kiro_retryable_protocol_failure"
           : declaredDisposition === "terminal_refusal"
@@ -975,16 +1013,6 @@ export class KiroExecutor extends BaseExecutor {
         );
         return;
       }
-      if (state.toolValidationError) {
-        fail(
-          controller,
-          "invalid_tool_call",
-          "invalid_kiro_tool_call",
-          state.toolValidationError,
-          { transport_state: state.transportState, stop_disposition: "retryable_protocol_failure" }
-        );
-        return;
-      }
       try {
         emitTools(controller);
       } catch (error) {
@@ -997,6 +1025,22 @@ export class KiroExecutor extends BaseExecutor {
         );
         return;
       }
+      // Fail only when the turn has nothing usable left. emitTools() validates
+      // per tool and drops just the unusable ones, so this has to run AFTER it:
+      // before, the rejected tool was still buffered and tools.size was never 0.
+      // A turn that also produced text keeps that text -- the dropped call is
+      // logged, not fatal.
+      if (state.toolValidationError && !state.hasToolCalls &&
+          !state.hasText && !state.hasReasoning && !state.hasCode) {
+        fail(
+          controller,
+          "invalid_tool_call",
+          "invalid_kiro_tool_call",
+          state.toolValidationError,
+          { transport_state: state.transportState, stop_disposition: "retryable_protocol_failure" }
+        );
+        return;
+      }
 
       const hasOutput = state.hasText || state.hasReasoning || state.hasCode || state.hasToolCalls;
       if (!hasOutput && !state.explicitStop) {
@@ -1011,7 +1055,13 @@ export class KiroExecutor extends BaseExecutor {
       }
 
       const disposition = stopDisposition(state.stopReason, state.hasToolCalls);
-      if (["retryable_protocol_failure", "terminal_incomplete", "terminal_refusal", "unknown_failure"].includes(disposition)) {
+      // Same reasoning as declaredTruncatedAfterOutput above.
+      const truncatedAfterOutput = disposition === "terminal_incomplete" &&
+        KIRO_TRUNCATION_STOP_REASONS.has(state.stopReason) && state.chunkIndex > 0;
+      if (truncatedAfterOutput) {
+        console.error(`[Kiro] truncated after ${state.chunkIndex} chunk(s) (stop_reason=${state.stopReason}); closing as length`);
+      }
+      if (!truncatedAfterOutput && ["retryable_protocol_failure", "terminal_incomplete", "terminal_refusal", "unknown_failure"].includes(disposition)) {
         const code = disposition === "retryable_protocol_failure"
           ? "kiro_retryable_protocol_failure"
           : disposition === "terminal_refusal"
@@ -1041,18 +1091,24 @@ export class KiroExecutor extends BaseExecutor {
           total_tokens: prompt + completion
         };
       }
-      const finishReason = state.hasToolCalls
-        ? "tool_calls"
-        : disposition === "length"
-          ? "length"
-          : "stop";
+      const finishReason = truncatedAfterOutput
+        ? "length"
+        : state.hasToolCalls
+          ? "tool_calls"
+          : disposition === "length"
+            ? "length"
+            : "stop";
       controller.enqueue(sseChunk({}, finishReason, state.usage));
       controller.enqueue(encoder.encode(SSE_DONE));
       state.finished = true;
       options.onTerminalState?.(diagnostics({
         terminal_provenance: state.terminalProvenance || "clean_eventstream_eof",
         transport_state: state.transportState,
-        stop_disposition: disposition
+        // Report what this exit actually did, not the raw disposition. The
+        // integrity gate re-derives its verdict from stop_disposition, so
+        // reporting "terminal_incomplete" for a turn we deliberately kept made
+        // it discard the very bytes we just released to the client.
+        stop_disposition: truncatedAfterOutput ? "length" : disposition
       }));
     };
 

open-sse/translator/request/claude-to-kiro.js

@@ -287,6 +287,18 @@ export function claudeToKiroRequest(model, body, stream, credentials) {
     toolSpecs,
     nameMap,
   });
+  // canonicalizeKiroConversation() already ran its second-chance repair (flatten
+  // every structured tool turn to text, then re-validate). A body that is STILL
+  // invalid here cannot be made shippable, and Kiro answers it with
+  // 400 {"message":"Improperly formed request.","reason":"REQUEST_BODY_INVALID"}.
+  // Fail locally instead: chatCore turns a falsy return into a 400 without
+  // spending an upstream call or a per-account cooldown. The taxonomy
+  // (role:N | pair:N | id:N | spec:N | orphan:0 | current) names the offending
+  // turn so the shape can be diagnosed from the log alone.
+  if (!canonical.valid) {
+    console.error(`[Kiro] refusing invalid conversation (claude → kiro): ${(canonical.errors || []).join(", ") || "unknown"} | turns=${(canonical.history || []).length + 1}`);
+    return null;
+  }
   const replayCurrent = canonical.currentMessage.userInputMessage;
   const userInputMessage = {
     content: replayCurrent.content || "",

open-sse/translator/request/openai-to-kiro.js

@@ -379,6 +379,18 @@ export function openaiToKiroRequest(model, body, stream, credentials) {
     toolSpecs,
     nameMap,
   });
+  // canonicalizeKiroConversation() already ran its second-chance repair (flatten
+  // every structured tool turn to text, then re-validate). A body that is STILL
+  // invalid here cannot be made shippable, and Kiro answers it with
+  // 400 {"message":"Improperly formed request.","reason":"REQUEST_BODY_INVALID"}.
+  // Fail locally instead: chatCore turns a falsy return into a 400 without
+  // spending an upstream call or a per-account cooldown. The taxonomy
+  // (role:N | pair:N | id:N | spec:N | orphan:0 | current) names the offending
+  // turn so the shape can be diagnosed from the log alone.
+  if (!canonical.valid) {
+    console.error(`[Kiro] refusing invalid conversation (openai → kiro): ${(canonical.errors || []).join(", ") || "unknown"} | turns=${(canonical.history || []).length + 1}`);
+    return null;
+  }
   const replayCurrent = canonical.currentMessage.userInputMessage;
 
   const payload = {

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

@@ -75,6 +75,15 @@ export function kiroToClaudeResponse(chunk, state) {
         ? data.usage.completion_tokens
         : 0;
     state.usage = { input_tokens: promptTokens, output_tokens: outputTokens };
+    // Claude clients read cache_read/cache_creation to price a turn and to size
+    // their prompt cache. Both spellings are accepted because the Kiro executor
+    // emits the Chat shape and passthrough responses use the nested details form.
+    const cacheRead = data.usage.cache_read_input_tokens
+      ?? data.usage.prompt_tokens_details?.cached_tokens;
+    const cacheCreation = data.usage.cache_creation_input_tokens
+      ?? data.usage.prompt_tokens_details?.cache_creation_tokens;
+    if (typeof cacheRead === "number") state.usage.cache_read_input_tokens = cacheRead;
+    if (typeof cacheCreation === "number") state.usage.cache_creation_input_tokens = cacheCreation;
   }
 
   // First chunk → emit message_start.
@@ -254,6 +263,13 @@ export function kiroToClaudeNonStreaming(data) {
     usage: {
       input_tokens: usage.prompt_tokens || 0,
       output_tokens: usage.completion_tokens || 0,
+      // Same cache preservation as the streaming path above.
+      ...(typeof (usage.cache_read_input_tokens ?? usage.prompt_tokens_details?.cached_tokens) === "number"
+        ? { cache_read_input_tokens: usage.cache_read_input_tokens ?? usage.prompt_tokens_details.cached_tokens }
+        : {}),
+      ...(typeof (usage.cache_creation_input_tokens ?? usage.prompt_tokens_details?.cache_creation_tokens) === "number"
+        ? { cache_creation_input_tokens: usage.cache_creation_input_tokens ?? usage.prompt_tokens_details.cache_creation_tokens }
+        : {}),
     },
   };
 }