chore(observability): prefix log lines with an ISO-8601 UTC timestamp

[shgew]

What

Prefix every log line emitted by logger.fmt, bootLog, and bootWarn with an ISO-8601 UTC timestamp:

2026-06-20T19:30:00.000Z [agentmemory] info Server listening on 3111

Quiet-mode buffered boot lines stay plain to keep the CLI summary clean.

Why

Docker logs and any persisted log file now carry per-line timestamps for downstream tail/grep/log-aggregator work. Without per-line timestamps, multi-container or multi-process log streams cannot be merged chronologically.

Tests

test/logger.test.ts (new file, 5 cases): info, warn, error, field serialization, non-serializable fallback, bootWarn, verbose bootLog. Targeted suite: 5/5 pass.

Compatibility

Format change for runtime log lines. CLI summary unchanged. No env changes.

Summary by CodeRabbit

• New Features
  • Log output now includes ISO-8601 (UTC) timestamps for improved event tracing and debugging visibility.
• Tests
  • Added coverage to verify stderr formatting for normal logging and boot-time messages, including behavior when extra fields cannot be serialized.

[vercel]

@shgew is attempting to deploy a commit to the rohitg00's projects Team on Vercel.

A member of the Team first needs to authorize it.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: c0cc415a-942a-4c0f-90f5-583dde107b44

📥 Commits

Reviewing files that changed from the base of the PR and between 27c9cfc and df985b5.

📒 Files selected for processing (1)

• test/logger.test.ts

🚧 Files skipped from review as they are similar to previous changes (1)

• test/logger.test.ts

---

📝 Walkthrough

Walkthrough

src/logger.ts gains a ts() helper that returns new Date().toISOString(). The fmt() formatter, bootLog(), and bootWarn() are updated to prepend this timestamp to every stderr line. A new Vitest suite in test/logger.test.ts spies on process.stderr.write and asserts the ISO-8601 prefix across all log paths.

Changes

Timestamp-prefixed log formatting

Layer / File(s)	Summary
ts() helper and fmt/boot timestamp updates src/logger.ts	Adds a ts() helper returning new Date().toISOString() and updates fmt(), bootLog(), and bootWarn() to prefix every stderr output line with ${ts()} [agentmemory] ….
Vitest timestamp assertions test/logger.test.ts	Adds ISO_PREFIX regex, spyStderr() mock helper, and a describe("logger timestamps") suite covering logger.info, logger.warn, logger.error (circular reference), bootWarn(), and bootLog() with verbosity toggling and quiet-mode behavior.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~10 minutes

Poem

🐇 Tick-tock, said the rabbit, time stamps every line,
ISO-8601 clocks now make the log output shine.
[agentmemory] speaks with a timestamp so neat,
bootWarn and bootLog keep a timestamped beat.
No circular reference can silence the clock—
Every error still ticks, every message unlocked! 🕐

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly and specifically describes the main change: adding ISO-8601 UTC timestamp prefixes to log lines, which is the core modification across logger.ts and logger.test.ts.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

_{✏️ Tip: You can configure your own custom pre-merge checks in the settings.}

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

---

Thanks for using CodeRabbit! It's free for OSS, and your support helps us grow. If you like it, consider giving us a shout-out.

❤️ Share

• X
• Mastodon
• Reddit
• LinkedIn

_{Comment @coderabbitai help to get the list of available commands and usage tips.}

[coderabbitai]

🧹 Nitpick comments (1)

test/logger.test.ts (1)

53-60: ⚡ Quick win

Add a quiet-mode regression test for bootLog.

Please add a case asserting setBootVerbose(false) + bootLog(...) does not call process.stderr.write; this guards the stated contract that quiet boot lines stay buffered/non-timestamped.

🤖 Prompt for AI Agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

In `@test/logger.test.ts` around lines 53 - 60, Add a new test case after the
existing verbose bootLog test that verifies the quiet-mode behavior of bootLog.
In this test, call setBootVerbose(false), then call bootLog with a test message,
and assert that the stderr spy mock was not called (or has zero calls),
confirming that quiet boot lines do not write to stderr but remain buffered
instead.

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Nitpick comments:
In `@test/logger.test.ts`:
- Around line 53-60: Add a new test case after the existing verbose bootLog test
that verifies the quiet-mode behavior of bootLog. In this test, call
setBootVerbose(false), then call bootLog with a test message, and assert that
the stderr spy mock was not called (or has zero calls), confirming that quiet
boot lines do not write to stderr but remain buffered instead.

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: 7ba7847a-90eb-497e-803a-c67dc8696281

📥 Commits

Reviewing files that changed from the base of the PR and between f6f9e3c and 27c9cfc.

📒 Files selected for processing (2)

• src/logger.ts
• test/logger.test.ts