feat(agents): add thinking time logging between tool calls (#244)

* feat(agents): add thinking time logging between tool calls

Adds a ThinkingTimer utility that tracks the gap between tool results and
the next tool call. When the gap exceeds 3 seconds, it logs the duration
with a stopwatch emoji (⏱️ 4.2s).

Uses performance.now() for high-resolution timing and Intl.NumberFormat
for rendering duration in seconds with optional fraction digits.

Integrated across all 5 agents: Claude, Codex, Cursor, Gemini, OpenCode.

Closes #127

* fix: adjusting tests for mocking performance.now.

* fix: reducing diff for claude.

* fix: rm unused args for claude.

* rm unused args for codex.

* fix: rm unused args for gemini.

* fix: rm unused args for opencode.

* mv THINKING_THRESHOLD.

* rev: I decided to pospone node:perf_hooks integration since it requires more comprehensive refactoring.

* fix: using Intl unit formatting.

* tests for ThinkingTimer.

* fix: narrow unit.

* fix: making durationFormatter a class instance property since using one agent per run.

* fix: inverting condition in markToolCall.

* thinking timer improvements and fix actions/checkout v6 auth

- thinking timer: use » chevron and "thought for X seconds" format
- thinking timer: add debug timestamps for sanity checking
- demote PID namespace isolation logs to debug
- remove redundant "setting up git authentication" log
- fix duplicate Authorization header with actions/checkout v6: clean up
  includeIf credential entries that v6 persists via external config files

Co-authored-by: Cursor <cursoragent@cursor.com>

* standardize tool call log prefix to » double chevron

Co-authored-by: Cursor <cursoragent@cursor.com>

* update timer tests for new thinking log format

Co-authored-by: Cursor <cursoragent@cursor.com>

---------

Co-authored-by: pullfrog[bot] <226033991+pullfrog[bot]@users.noreply.github.com>
Co-authored-by: Robin Tail <robin_tail@me.com>
Co-authored-by: Colin McDonnell <colinmcd94@gmail.com>
Co-authored-by: Cursor <cursoragent@cursor.com>

agents/opencode.ts

@@ -8,6 +8,7 @@ import { getIdleMs, markActivity } from "../utils/activity.ts";
 import { log } from "../utils/cli.ts";
 import { installFromNpmTarball } from "../utils/install.ts";
 import { spawn } from "../utils/subprocess.ts";
+import { ThinkingTimer } from "../utils/timer.ts";
 import { type AgentRunContext, agent } from "./shared.ts";
 
 async function installOpencode(): Promise<string> {
@@ -61,6 +62,7 @@ export const opencode = agent({
 
     const startTime = Date.now();
     let eventCount = 0;
+    const thinkingTimer = new ThinkingTimer();
 
     let output = "";
     let stdoutBuffer = ""; // buffer for incomplete lines across chunks
@@ -109,7 +111,7 @@ export const opencode = agent({
             markActivity(); // reset activity timeout on every event
             const handler = messageHandlers[event.type as keyof typeof messageHandlers];
             if (handler) {
-              await handler(event as never);
+              await handler(event as never, thinkingTimer);
             } else {
               // log unhandled event types for visibility
               log.info(
@@ -441,7 +443,7 @@ const messageHandlers = {
       currentStepType = null;
     }
   },
-  tool_use: (event: OpenCodeToolUseEvent) => {
+  tool_use: (event: OpenCodeToolUseEvent, thinkingTimer: ThinkingTimer) => {
     const toolName = event.part?.tool;
     const toolId = event.part?.callID;
     const parameters = event.part?.state?.input;
@@ -459,6 +461,7 @@ const messageHandlers = {
         stepHistory[stepHistory.length - 1].toolCalls.push(toolName);
       }
 
+      thinkingTimer.markToolCall();
       log.toolCall({
         toolName,
         input: parameters || {},
@@ -470,12 +473,14 @@ const messageHandlers = {
       }
     }
   },
-  tool_result: (event: OpenCodeToolResultEvent) => {
+  tool_result: (event: OpenCodeToolResultEvent, thinkingTimer: ThinkingTimer) => {
     // handle both new part structure and legacy flat structure
     const toolId = event.part?.callID || event.tool_id;
     const status = event.part?.state?.status || event.status || "unknown";
     const output = event.part?.state?.output || event.output;
 
+    thinkingTimer.markToolResult();
+
     if (toolId) {
       const toolStartTime = toolCallTimings.get(toolId);
       if (toolStartTime) {