devday

DevDay

A two-command journal for any git repo. Git captures what changed. You forget why by Friday. DevDay closes that gap.

DevDay is a Claude Code plugin — but the spec is self-contained. The same two commands run as plain shell, in any agent, in any git repository. Git is the only hard requirement.

• /devday-log — append a timestamped checkpoint to today's log while you work
• /devday — synthesise the day into a structured report at end of session

The methodology predates the skill. Hundreds of devlogs accumulated over months across every kind of git work — software, research, writing, infrastructure, talks, client work, side experiments — before this was packaged as a portable convention in May 2026.

Background read: DevDay — a two-command journal for any git project · Project page: smarason.is/en/projects/devday

Install — pick one

1. Tell your agent (works in Claude Code, Cursor, any agent that reads READMEs)

Paste this into the chat:

Install DevDay from https://github.com/Magnussmari/devday — read the README,
set up the /devday and /devday-log commands, and confirm when ready.

The agent reads this repo, places the skill and commands under ~/.claude/, and you're done. No flags, no manual paths.

2. Claude Code plugin marketplace

/plugin marketplace add Magnussmari/devday
/plugin install devday@devday

This installs DevDay as a managed Claude Code plugin — updates land via /plugin update.

3. One-line shell install

curl -fsSL https://raw.githubusercontent.com/Magnussmari/devday/main/install.sh | bash

Idempotent. Re-run anytime to update. Uninstall:

curl -fsSL https://raw.githubusercontent.com/Magnussmari/devday/main/install.sh | bash -s -- --uninstall

4. Manual (curl the files yourself)

# Skill
mkdir -p ~/.claude/skills/DevDay
curl -fsSL https://raw.githubusercontent.com/Magnussmari/devday/main/skills/devday/SKILL.md \
  > ~/.claude/skills/DevDay/SKILL.md

# Slash commands
mkdir -p ~/.claude/commands
curl -fsSL https://raw.githubusercontent.com/Magnussmari/devday/main/commands/devday.md \
  > ~/.claude/commands/devday.md
curl -fsSL https://raw.githubusercontent.com/Magnussmari/devday/main/commands/devday-log.md \
  > ~/.claude/commands/devday-log.md

First run

cd <any git repo>
/devday-log    # auto-orients; prints one line confirming project + log dir

From the second invocation onward, the orient step is invisible. If the auto-detected layout is not what you want, edit .devday/config.json once and commit. The skill respects the config from then on.

If you do not use Claude Code, skills/devday/SKILL.md is a self-contained specification — implement the same two commands in any agent or as plain shell scripts. Git is all the runtime you need.

Why this works when other journals do not

Three design choices, each from a real failure:

1. The only hard requirement is git. No database. No external app. No login. If you are in a git repository, DevDay works. If you are not, DevDay refuses to run and tells you so in one line. Knowledge-management experiments die on a second source of truth. Git is already the source of truth for code; the journal lives next to it.

2. The skill orients itself on first run. Phase 0 detects the project name from package.json / pyproject.toml / Cargo.toml / go.mod / repo basename — whichever it finds first. It probes a sensible log directory (docs/devlogs/, .devlogs/, falling back to creating one). It detects the default branch. It writes .devday/config.json so it never has to ask again. From the second invocation onward, orient is a one-line cache hit.