learn: retrospective learnings

[peco-engineer-bot]

Rolling retrospective learnings

This PR accumulates one dated section of learnings per day (from merged PRs and engineer-bot author runs) until it is merged; merging it starts a fresh one. The bot never writes the canonical log directly.

Latest update 2026-09-09: 1 new learning(s) since 2026-09-08T17:27:48Z.

[peco-review-bot]

✅ No issues identified by the review bot.

[peco-review-bot]

✅ No issues identified by the review bot.

[peco-review-bot]

✅ No issues identified by the review bot.

[peco-review-bot]

✅ No issues identified by the review bot.

[github-actions]

Thanks for your contribution! To satisfy the DCO policy in our contributing guide every commit message must include a sign-off message. One or more of your commits is missing this message. You can reword previous commit messages with an interactive rebase (git rebase -i main).

[peco-review-bot]

✅ No issues identified by the review bot.

[github-actions]

Thanks for your contribution! To satisfy the DCO policy in our contributing guide every commit message must include a sign-off message. One or more of your commits is missing this message. You can reword previous commit messages with an interactive rebase (git rebase -i main).

[peco-review-bot]

✅ No issues identified by the review bot.

[github-actions]

Thanks for your contribution! To satisfy the DCO policy in our contributing guide every commit message must include a sign-off message. One or more of your commits is missing this message. You can reword previous commit messages with an interactive rebase (git rebase -i main).

[peco-review-bot]

✅ No issues identified by the review bot.

[github-actions]

Thanks for your contribution! To satisfy the DCO policy in our contributing guide every commit message must include a sign-off message. One or more of your commits is missing this message. You can reword previous commit messages with an interactive rebase (git rebase -i main).

[peco-review-bot]

Verdict: 1 Nit

Looks good — this PR only appends dated retrospective learning entries to .claude/knowledge/learning-log.md; no executable code changes, so nothing to check for correctness/security/tests. One cosmetic nit: the "No learnings have been recorded yet" placeholder line is now stale since entries follow it.

Other findings

• ⚪ Nit — The intro placeholder paragraph ("No learnings have been recorded yet — the first retrospective PR will append the initial dated section below.") is now stale: several dated sections follow it. Consider removing or rewording the placeholder now that entries exist, so the header no longer contradicts the body. Purely cosmetic — the retrospective flow appends below it as designed.

[github-actions]

Thanks for your contribution! To satisfy the DCO policy in our contributing guide every commit message must include a sign-off message. One or more of your commits is missing this message. You can reword previous commit messages with an interactive rebase (git rebase -i main).

[peco-review-bot]

Verdict: 1 Low

Docs-only change: appends dated retrospective learnings to the knowledge log. Content is well-formed; one low-severity doc inconsistency — the "No learnings have been recorded yet" placeholder paragraph is now stale and contradicts the appended ## Entries section. Nit: consider a blank line between that paragraph and the new ## Entries heading for cleaner rendering.

[peco-review-bot]

🔵 Low — This PR appends an ## Entries section with many dated learnings directly below the placeholder paragraph that still reads "No learnings have been recorded yet — the first retrospective PR will append the initial dated section below." That sentence is now stale and self-contradictory: learnings clearly have been recorded. Since the append flow is now active, the placeholder paragraph should be removed (or rewritten) so the file's intro no longer contradicts the entries immediately following it.