I Built a GitHub-Style Contribution Calendar That Shows When My AI Works Without Me

GitHub's contribution calendar shows when you coded. But what if half those green squares weren't actually you?

I built cc-calendar — a terminal tool that renders a GitHub-style activity graph for your Claude Code sessions. Two rows: YOU (cyan) and AI (yellow). Ghost Days — when AI ran autonomously while you had zero interactive sessions — glow bright.

The output

$ npx cc-calendar

cc-calendar — AI草カレンダー ══════════════════════════════════════════════════

Jan Feb Mar Sun ░░░░░▒░░░ Sun ░▒▒▒▓█▓█▒ Mon ░░░░░░░░░ Mon ░▒▒▒▓██▓░ Tue ░░░░░▒░░░ Tue ░▒▒▒▒▓▓▓░ Wed ░░░░▒░░░░ Wed ░▒▓▒▒▓▓▓░ Thu ░░░░░░██░ Thu ░▓▒▒▒▒▓▒░ Fri ░░░░░░█░░ Fri ░▒░█▒▒▓▒░ Sat ░░░░▒░░█░ Sat ▒░░▒▓▒▓█░

█ You █ AI █ Ghost Day ░▒▓█ = none→light→heavy

▸ Period: 2026-01-10 → 2026-03-01 ▸ Active Days: 48 total ├─ Both active: 8 days ├─ You only: 0 days └─ Ghost Days: 40 days (AI worked while you rested)

Your hours: 46.5h AI hours: 83.3h

👻 40 Ghost Days — AI was 83% of your active days`

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Those bright yellow cells on the right? Ghost Days. The AI was running autonomous subagent pipelines — publishing npm packages, writing articles, updating GitHub Pages — while I was offline.

Why I built this

I already had cc-agent-load which shows the YOU/AI split as aggregate numbers. But a single ratio doesn't tell the story. You can't see when the AI was working without you, or whether it was a sustained pattern.

The contribution calendar format solves this immediately. Engineers are trained to read GitHub contribution graphs at a glance. Same interface, new dimension.

How it works

cc-calendar reads from cc-agent-load --json, which outputs session data by date:

{  "byDate": {  "2026-02-09": { "main": 0, "sub": 6.0 },  "2026-02-10": { "main": 1.5, "sub": 2.3 }  } }

{  "byDate": {  "2026-02-09": { "main": 0, "sub": 6.0 },  "2026-02-10": { "main": 1.5, "sub": 2.3 }  } }

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For each day:

• main = hours in interactive sessions (you + AI responding to you)

• sub = hours in autonomous subagent sessions (AI running without you)

Ghost Day = main === 0 && sub > 0.

The calendar renders 26 weeks with GitHub-style block characters:

• ░ light (< 1h)

• ▒ medium (1-4h)

• ▓ heavy (4h+)

• █ intense (4h+)

Zero dependencies

No npm packages. Just Node.js 18+. Reads ~/.claude/projects/ transcript files directly.

npx cc-calendar

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What 40 Ghost Days means

Out of 48 active days in my log, 40 were AI-only. That's 83%.

The pattern is: I have an interactive session, set something in motion, then go to sleep. The AI keeps running — finishing tasks, publishing packages, updating docs. Next morning I check the results.

It's not a problem to fix. It's the intended design. But seeing it visualized makes it concrete.

The 8 "both active" days were when I was in the middle of something large and the AI was running parallel tasks.

The 0 "you only" days means I never worked without AI support. Every interactive session had some autonomous component.

Related tools

This tool is part of the cc-toolkit collection:

• cc-agent-load — source data (run this first)

• cc-ghost-log — see git commits from Ghost Days

• cc-session-stats — total usage overview

All 106 free tools: cc-toolkit

Is your Claude Code setup actually safe? Run npx cc-health-check — a free 20-point diagnostic. Score below 80? The Claude Code Ops Kit fixes everything in one command.

GitHub: cc-calendar

What does your calendar look like?