log-changes

name	log-changes
description	Use when asked to update the changelog, document version changes, prepare a release, or add entries for recent work. Handles CHANGELOG.md updates following Keep a Changelog format and Semantic Versioning. Do NOT use for committing or creating release notes outside CHANGELOG.md.
metadata	{"author":"Serghei Iakovlev","version":"1.2","category":"documentation"}

Changelog Maintenance

The changelog records notable changes to the distributed software. Every entry must answer: "Does this change affect someone who uses, upgrades, deploys, or integrates with the project?" If not, omit it.

Format authority: Keep a Changelog 1.1.0 and Semantic Versioning 2.0.0.

Project constants

Detect the following constants from the project itself - do not ask the user unless detection fails. Inspect, in order: existing CHANGELOG.md entries, project documentation (README.md, CONTRIBUTING.md, docs/), and recent git commit messages.

1. GitHub repository slug (OWNER/REPO). Read existing comparison links at the bottom of CHANGELOG.md (preferred). Fall back to git remote get-url origin and parse the slug from the URL.

2. Issue tracker. Look for tracker references in existing CHANGELOG entries, PR templates, contributing docs, and recent commit messages:

   • GitHub Issues - links of the form https://github.com/OWNER/REPO/issues/NNN, or closing keywords closes/fixes/resolves #NNN in commit/PR bodies.
   • Jira - task keys of the form [A-Z]+-[0-9]+ (e.g. ABC-123) or links to *.atlassian.net/browse/....
   • Linear - keys like ENG-123 or links to https://linear.app/....
   • Other trackers - distinct ID schemes or links in commit/PR bodies.

   For non-GitHub trackers, also detect the tracker base URL and the project key prefix (e.g. BP, ABC, ENG).

3. Subsystem labels. Read existing CHANGELOG entries to learn which subsystem prefixes the project already uses (e.g. API:, CLI:, Auth:). If none exist, propose labels that match the project's top-level directory or package layout. The human reviewer will correct any that are wrong.

Use the detected values everywhere a project key, tracker URL, or GitHub URL is needed. If a constant cannot be determined with confidence, ask the user once before proceeding. Do not guess or invent values.

When to use

• Adding entries for new features, fixes, or breaking changes.
• Preparing a release: moving Unreleased entries under a versioned heading.
• Creating CHANGELOG.md from scratch when it does not exist.

Workflow

Step 1: Read the current changelog

CHANGELOG.md, if it exists, lives at the repository root. Read it first. If the file does not exist, create it from assets/changelog-template.md (see Step 5).

Step 2: Gather changes

The merged PR is the atomic unit of a changelog entry - not the commit. A single PR often contains the feature commit, follow-up fixes, review feedback, test additions, and docs updates. These are one logical change and produce one changelog bullet. Never split a PR's commits into separate entries.

2a: Identify the release window

# Last tag, its date (window start), and recent tags for context
LAST_TAG=$(git describe --tags --abbrev=0 2>/dev/null)
git log -1 --format="%ai" "$LAST_TAG"
git tag --sort=-version:refname | head -10

If no tags exist, treat the entire git history as the unreleased window. The release window is: tag date (exclusive) → today.

2b: List merged PRs in the window

Primary: milestone-based (when the project sets milestones on PRs; replace MILESTONE_PREFIX with the prefix the project uses, e.g. M10):

gh pr list --state merged --limit 100 \
  --json number,title,mergedAt,milestone,labels \
  --jq '.[] | select(.milestone != null and (.milestone.title | startswith("MILESTONE_PREFIX")))
        | "\(.number)\t\(.mergedAt | split("T")[0])\t\(.title)"' \
  | sort -t$'\t' -k2

Fallback: date-based (when milestones are not set; replace YYYY-MM-DD with the tag date):

gh pr list --state merged --limit 200 \
  --json number,title,mergedAt,labels \
  --jq '.[] | select(.mergedAt >= "YYYY-MM-DDT00:00:00Z")
        | "\(.number)\t\(.mergedAt | split("T")[0])\t\(.title)"' \
  | sort -t$'\t' -k2

For non-GitHub trackers, also fetch resolved tasks within the same window using the tracker's search API or web UI - see references/trackers.md for the section matching the detected tracker.

2c: Inspect individual PRs and link to tracker tasks

# PR title, body (scope/intent), and constituent commits
gh pr view <NUMBER> --json title,body --jq '"\(.title)\n\(.body)"' | head -40
gh pr view <NUMBER> --json commits --jq '.commits[].messageHeadline'

Extract issue/task references from the PR body using the extraction commands in references/trackers.md for the tracker detected in Step 1. Read each linked issue/task for the user-facing problem statement: PR titles are implementation-focused, tracker items are user/operator-focused.

Use the PR body's Scope & Context section (when present) to understand the user-facing or operator-facing impact. Do not rely on git log --oneline - it shows commits, not logical changes.

If the user describes changes verbally, use that as the primary source.

Step 3: Filter - decide what belongs

The changelog records notable changes to the distributed software. A change is notable when it alters what a consumer of the project can observe: new capabilities, changed behavior, fixed bugs, security patches, removed features, or deprecation notices.

Apply the following filter to every commit or change before writing an entry.

ALWAYS include:

Signal	Why it matters to consumers
New user-facing feature (CLI flag, integration, config option, API surface, UI capability)	Consumers discover new capabilities
Changed behavior of existing feature	Consumers must adjust usage
Bug fix for incorrect behavior	Consumers know issues are resolved
Security or vulnerability fix	Operators must act on upgrades
Deprecation of public interface	Consumers prepare for removal
Removal of feature or public interface	Consumers must adapt before upgrading
Performance improvement with measurable impact	Consumers benefit from upgrading
New or changed persistence schema (migration)	Operators plan upgrade procedures
Changed CLI flags, env vars, deployment, or config file format	Operators must update deployment config

NEVER include - these are noise, not signal:

Noise	Why it does not belong
Internal variable/function/type renames	No observable effect on consumers
Code formatting, whitespace, linting fixes	No observable effect on consumers
Test-only changes (new tests, test refactors)	Not shipped to consumers
CI/CD pipeline changes (workflows, actions)	Not shipped to consumers
Dotfile changes (.gitignore, .github/*, CODEOWNERS)	Not shipped to consumers
Documentation-only changes (README, CLAUDE.md, AGENTS.md, comments)	Not shipped to consumers
Merge commits	Infrastructure artifact, not a change
Internal refactoring with no behavior change	No observable effect on consumers
Dev-only dependency bumps	Not shipped to consumers
Project scaffolding and repo housekeeping	Not shipped to consumers

Edge cases - include only when the threshold is met:

Change	Include when...	Omit when...
Dependency bump	Major version, security fix, or changed behavior	Routine patch/minor with no user impact
Refactoring	It changes observable performance, error messages, or log output	Purely internal restructuring
New internal module/package	It introduces a new adapter or public API surface	It reorganizes existing code
ADR or architecture doc update	It records a decision that changes system behavior	It clarifies existing behavior

When in doubt, ask: "If I were a consumer of this project reading this before upgrading, would I need to know this?" If the answer is no, leave it out.

Step 4: Classify each change

Place every surviving entry under exactly one category:

Category	When to use
Added	New user-facing capability: CLI command, integration, config option, API surface, UI capability
Changed	Existing behavior altered in a way consumers can observe
Deprecated	Still works but scheduled for removal in a future version
Removed	Previously available feature or interface deleted
Fixed	Bug fix - incorrect behavior corrected
Security	Vulnerability patch, dependency CVE fix

Writing rules:

• One bullet per logical change between releases. A logical change is everything the consumer observes as a single unit of value. It may span multiple PRs and commits if they all deliver, refine, or fix the same capability within the release window.
• Fold within-release churn. If a feature is introduced in one PR and then corrected, polished, or adjusted in subsequent PRs before the release ships, all of that work produces one changelog entry describing the final state. From the consumer's perspective there was no intermediate broken state - only the delivered result.
• Fold sub-fixes into the feature entry. If a PR introduces a feature and also fixes a bug found during its implementation, describe the fix as part of the feature bullet. Only create a standalone Fixed entry when the PR's sole purpose is a bug fix that is independent of any in-progress feature.
• Reference the issue/task when one exists; fall back to the PR otherwise. Each bullet ends with a parenthetical reference using a full URL (plain #NNN or bare tracker keys are not clickable in rendered markdown). When a tracker issue/task is linked from the PR, reference the issue/task only - not also the PR. When multiple distinct issues/tasks are linked, list all of them. See references/trackers.md for the URL format matching the detected tracker.
• Start each bullet with what changed, not with "Fixed" or "Added" (the heading already says that).
• Be specific: "coroutine 'main' was never awaited bug after async migration" not "Fixed async bug".
• Identify the subsystem when it helps locate the change, using the labels detected in Step 1 (e.g. API:, CLI:, Auth:, Dashboard:).
• Reference types or functions in backticks when they help the reader.
• Do not copy git commit messages verbatim - rewrite for a human reader.

Step 5: Write the entry

Use assets/changelog-template.md as the structural template when creating CHANGELOG.md from scratch or adding the first versioned section. The template covers the preamble, [Unreleased] placeholder, a versioned section, and bottom comparison links.

Structural rules:

• Reverse chronological order (newest first).
• [Unreleased] section always present at the top.
• Dates in ISO 8601 (YYYY-MM-DD).
• Comparison links at the bottom for every version.
• Empty categories are omitted (no ### Removed if nothing was removed).

Step 6: Determine the version bump

When cutting a release, choose the version number:

Bump	Trigger
Major	Breaking API/CLI change for users or operators, removed public functionality
Minor	New feature, backward-compatible behavior change
Patch	Bug fix, security patch

To cut a release:

1. Replace ## [Unreleased] with ## [X.Y.Z] - YYYY-MM-DD.
2. Add a fresh empty ## [Unreleased] section above it.
3. Update the comparison links at the bottom.

Step 7: Verify

• Every entry passes the filter from Step 3 (no noise).
• Newest version is at the top.
• Every version has a date (except Unreleased).
• Bottom links are correct and complete.
• No empty category headings.
• No git-log copy-paste - entries are human-readable.
• Entries identify the subsystem where helpful.
• Tracker references are full URLs, not bare keys or plain #NNN.
• When an issue/task exists, the bullet references the issue/task only - not also the PR.
• If the project's tracker is not GitHub Issues: no https://github.com/OWNER/REPO/issues/NNN links are present in the changelog.

Error Recovery

Problem	Fix
Missing comparison links	Reconstruct from git tag --sort=-version:refname
Duplicate entries	Deduplicate, keep the more descriptive version
Entry under wrong category	Move it; if ambiguous, prefer Changed over Added
No tags in repository	Use commit SHAs in comparison links as a temporary measure
Noise entry slipped in	Remove it - a leaner changelog is more trustworthy

Anti-Patterns

Anti-pattern	Why it's wrong	Correct approach
One entry per commit	Commits are implementation steps, not logical changes. A 6-commit PR produces one changelog bullet.	Use gh pr list to enumerate PRs; write one bullet per logical change.
Using git log --oneline as the primary source	Produces commit-level noise: test commits, review feedback, merge commits, formatting fixes.	Query merged PRs via gh pr list --state merged filtered by milestone or date range since the last git tag.
Plain #NNN references	Not clickable in rendered markdown - readers must manually construct the URL to navigate to the change.	Use full URLs (see references/trackers.md).
Including both the issue/task and the PR in one bullet	Doubles the noise and misleads the reader: the issue/task already describes the user-visible problem, the PR is its implementation.	Reference the issue/task only when one exists; fall back to the PR only when no issue/task is available.
Bare tracker keys (e.g. BP-123, ENG-42)	Not clickable; readers cannot navigate to the task without knowing the tracker URL.	Use the full tracker URL (see references/trackers.md).
GitHub Issue links in changelog when the project's tracker is not GitHub Issues	The detected tracker is the authoritative source for task references. Adding /issues/NNN links is misleading and breaks over time as the GitHub Issues tab is unused.	Use tracker links for all task references; GitHub links remain only for PRs.