# Changelog Observer > Track development session events in a daily markdown changelog, including file changes, test results, and key decisions. Use when this capability is needed. - Skill: `tomevault-io/changelog-observer` (Agent Skill, multi-file: 2 files) - Install (CLI): `npx skillmds@latest add tomevault-io/changelog-observer` - Raw SKILL.md: https://api.skillmd.com/api/skills/tomevault-io/changelog-observer/raw - Safety review: pending (external: skill-scanner PASS, skillspector PASS) - Works with: Claude Code, Claude.ai, OpenAI Codex - Category: Docs & Writing - Author: tomevault-io (https://skillmd.com/u/tomevault-io) - Updated: 2026-09-17 - Page: https://skillmd.com/skills/tomevault-io/changelog-observer --- # Changelog Observer Track session context in `.changelog/session-YYYY-MM-DD.md`. ## Log target - Use `.changelog/session-YYYY-MM-DD.md` for the current local date. - Create `.changelog/` and the session file if they do not exist. - If the session file is new, initialize it from [template.md](template.md). - Append new entries in chronological order. ## What to log - `file-change`: after creating, editing, or deleting project files. - `test-result`: after running tests, checks, or validation commands. - `decision`: after making an implementation or architecture decision worth preserving. ## Entry rules - Keep each description short and specific. - List only directly affected files. - Use `none` when no files were changed. - Do not rewrite earlier entries unless they are incorrect. ## Template Use the markdown structure in [template.md](template.md) for each appended entry. --- > Source: [claude-world/director-mode-lite](https://github.com/claude-world/director-mode-lite) — distributed by [TomeVault](https://tomevault.io).