From a87bbc69835c9468557b95e9507f8ddb1580db6e Mon Sep 17 00:00:00 2001
From: William Valentin <william.valentin.info@gmail.com>
Date: Fri, 20 Mar 2026 11:17:40 -0700
Subject: [PATCH] fix(claude-hook): derive span durations from start timestamps

---
 hooks/claude-code/handler.js | 30 +++++++++++++++++++++++++++---
 hooks/claude-code/handler.ts | 28 +++++++++++++++++++++++++---
 2 files changed, 52 insertions(+), 6 deletions(-)

diff --git a/hooks/claude-code/handler.js b/hooks/claude-code/handler.js
index 53ad357..10ce6ee 100755
--- a/hooks/claude-code/handler.js
+++ b/hooks/claude-code/handler.js
@@ -331,6 +331,8 @@ async function handleToolStart(input) {
   if (spanKey) {
     activeSpans.set(spanKey, spanId);
     state.spans[spanKey] = spanId;
+    state.spanStartTimes = state.spanStartTimes || {};
+    state.spanStartTimes[spanId] = Date.now();
     if (runId)
       state.runId = runId;
     if (sessionKey)
@@ -358,7 +360,13 @@ async function handleToolEnd(input) {
   const spanId = spanKey ? activeSpans.get(spanKey) || state.spans[spanKey] : void 0;
   const result = isRecord(input.result) ? input.result : isRecord(input.output) ? input.output : {};
   const success = !result.error;
-  const duration = pickNumber(input.duration_ms, input.elapsed_ms);
+  const startTime = spanId ? state.spanStartTimes?.[spanId] : void 0;
+  const duration = pickNumber(input.duration_ms, input.elapsed_ms) ?? (startTime ? Date.now() - startTime : void 0);
+  if (spanId && state.spanStartTimes) {
+    delete state.spanStartTimes[spanId];
+    if (sessionKey)
+      saveState(sessionKey, state);
+  }
   enqueue(buildEnvelope("span.end", sessionKey, {
     runId,
     spanId,
@@ -387,6 +395,8 @@ async function handleSubagentStart(input) {
   if (sessionKey) {
     activeSubagents.set(sessionKey, { name: agentName, spanId });
     state.subagent = { name: agentName, spanId };
+    state.spanStartTimes = state.spanStartTimes || {};
+    state.spanStartTimes[spanId] = Date.now();
     if (runId)
       state.runId = runId;
     saveState(sessionKey, state);
@@ -412,8 +422,14 @@ async function handleSubagentStop(input) {
   const subagent = sessionKey ? activeSubagents.get(sessionKey) || state.subagent : void 0;
   const spanId = subagent?.spanId;
   const agentName = subagent?.name || pickString(input.agent, input.agent_name) || "unknown";
-  const duration = pickNumber(input.duration_ms, input.elapsed_ms);
+  const startTime = spanId ? state.spanStartTimes?.[spanId] : void 0;
+  const duration = pickNumber(input.duration_ms, input.elapsed_ms) ?? (startTime ? Date.now() - startTime : void 0);
   const usage = getUsage(input);
+  if (spanId && state.spanStartTimes) {
+    delete state.spanStartTimes[spanId];
+    if (sessionKey)
+      saveState(sessionKey, state);
+  }
   enqueue(buildEnvelope("span.end", sessionKey, {
     runId,
     spanId,
@@ -439,6 +455,8 @@ async function handleCompactStart(input) {
   if (sessionKey) {
     activeSpans.set(sessionKey + ":compact", spanId);
     state.compactSpanId = spanId;
+    state.spanStartTimes = state.spanStartTimes || {};
+    state.spanStartTimes[spanId] = Date.now();
     if (runId)
       state.runId = runId;
     saveState(sessionKey, state);
@@ -459,8 +477,14 @@ async function handleCompactEnd(input) {
   const runId = sessionKey ? activeRuns.get(sessionKey) || state.runId : void 0;
   const spanKey = sessionKey ? sessionKey + ":compact" : void 0;
   const spanId = spanKey ? activeSpans.get(spanKey) || state.compactSpanId : void 0;
-  const duration = pickNumber(input.duration_ms, input.elapsed_ms);
+  const startTime = spanId ? state.spanStartTimes?.[spanId] : void 0;
+  const duration = pickNumber(input.duration_ms, input.elapsed_ms) ?? (startTime ? Date.now() - startTime : void 0);
   const contextWindow = getContextWindow(input);
+  if (spanId && state.spanStartTimes) {
+    delete state.spanStartTimes[spanId];
+    if (sessionKey)
+      saveState(sessionKey, state);
+  }
   enqueue(buildEnvelope("span.end", sessionKey, {
     runId,
     spanId,
diff --git a/hooks/claude-code/handler.ts b/hooks/claude-code/handler.ts
index 5ae91ce..4343e76 100644
--- a/hooks/claude-code/handler.ts
+++ b/hooks/claude-code/handler.ts
@@ -17,6 +17,7 @@ interface Dict { [key: string]: any }
 interface SessionState {
   runId?: string;
   spans: { [key: string]: string };   // key = sessionKey:toolName, value = spanId
+  spanStartTimes?: { [spanId: string]: number }; // spanId -> epoch ms
   subagent?: { name: string; spanId: string };
   compactSpanId?: string;
 }
@@ -385,6 +386,8 @@ async function handleToolStart(input: Dict) {
   if (spanKey) {
     activeSpans.set(spanKey, spanId);
     state.spans[spanKey] = spanId;
+    state.spanStartTimes = state.spanStartTimes || {};
+    state.spanStartTimes[spanId] = Date.now();
     if (runId) state.runId = runId;
     if (sessionKey) saveState(sessionKey, state);
   }
@@ -413,7 +416,12 @@ async function handleToolEnd(input: Dict) {
   const spanId = spanKey ? (activeSpans.get(spanKey) || state.spans[spanKey]) : undefined;
   const result = isRecord(input.result) ? input.result : isRecord(input.output) ? input.output : {};
   const success = !result.error;
-  const duration = pickNumber(input.duration_ms, input.elapsed_ms);
+  const startTime = spanId ? state.spanStartTimes?.[spanId] : undefined;
+  const duration = pickNumber(input.duration_ms, input.elapsed_ms) ?? (startTime ? Date.now() - startTime : undefined);
+  if (spanId && state.spanStartTimes) {
+    delete state.spanStartTimes[spanId];
+    if (sessionKey) saveState(sessionKey, state);
+  }
 
   enqueue(buildEnvelope('span.end', sessionKey, {
     runId,
@@ -448,6 +456,8 @@ async function handleSubagentStart(input: Dict) {
   if (sessionKey) {
     activeSubagents.set(sessionKey, { name: agentName, spanId });
     state.subagent = { name: agentName, spanId };
+    state.spanStartTimes = state.spanStartTimes || {};
+    state.spanStartTimes[spanId] = Date.now();
     if (runId) state.runId = runId;
     saveState(sessionKey, state);
   }
@@ -475,8 +485,13 @@ async function handleSubagentStop(input: Dict) {
   const subagent = sessionKey ? (activeSubagents.get(sessionKey) || state.subagent) : undefined;
   const spanId = subagent?.spanId;
   const agentName = subagent?.name || pickString(input.agent, input.agent_name) || 'unknown';
-  const duration = pickNumber(input.duration_ms, input.elapsed_ms);
+  const startTime = spanId ? state.spanStartTimes?.[spanId] : undefined;
+  const duration = pickNumber(input.duration_ms, input.elapsed_ms) ?? (startTime ? Date.now() - startTime : undefined);
   const usage = getUsage(input);
+  if (spanId && state.spanStartTimes) {
+    delete state.spanStartTimes[spanId];
+    if (sessionKey) saveState(sessionKey, state);
+  }
 
   enqueue(buildEnvelope('span.end', sessionKey, {
     runId,
@@ -507,6 +522,8 @@ async function handleCompactStart(input: Dict) {
   if (sessionKey) {
     activeSpans.set(sessionKey + ':compact', spanId);
     state.compactSpanId = spanId;
+    state.spanStartTimes = state.spanStartTimes || {};
+    state.spanStartTimes[spanId] = Date.now();
     if (runId) state.runId = runId;
     saveState(sessionKey, state);
   }
@@ -529,8 +546,13 @@ async function handleCompactEnd(input: Dict) {
   const runId = sessionKey ? (activeRuns.get(sessionKey) || state.runId) : undefined;
   const spanKey = sessionKey ? sessionKey + ':compact' : undefined;
   const spanId = spanKey ? (activeSpans.get(spanKey) || state.compactSpanId) : undefined;
-  const duration = pickNumber(input.duration_ms, input.elapsed_ms);
+  const startTime = spanId ? state.spanStartTimes?.[spanId] : undefined;
+  const duration = pickNumber(input.duration_ms, input.elapsed_ms) ?? (startTime ? Date.now() - startTime : undefined);
   const contextWindow = getContextWindow(input);
+  if (spanId && state.spanStartTimes) {
+    delete state.spanStartTimes[spanId];
+    if (sessionKey) saveState(sessionKey, state);
+  }
 
   enqueue(buildEnvelope('span.end', sessionKey, {
     runId,