checkpoint

A session handoff tool that records the current task, branch, loaded documents, completed work, remaining work, and next action in project files. A branch is a separate line of changes in version control.

In plain words
What is it for?
Use it before ending a task, before a long operation, or when the conversation is getting full. It saves state in todo.md and records new lessons in lessons.md.
Why use it?
It prevents important context from being lost when a coding session ends or becomes too large to continue comfortably. It gives the next session a clear starting point.

Skill for Claude CodeCodex

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add skills/brain-bootstrap/claude-code-brain-bootstrap/checkpoint
Any agent
npx skills add brain-bootstrap/claude-code-brain-bootstrap --skill checkpoint
Clone the repo
git clone --depth 1 https://github.com/brain-bootstrap/claude-code-brain-bootstrap

Made for: Claude Code, Codex.

Per session 39 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 377 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00039 $0.00377
Opus 5 $0.00019 $0.00188
Sonnet 5 $0.00008 $0.00075
Haiku 4.5 $0.00004 $0.00038

Measured 2d ago against content hash 91ac030b740f, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

checkpoint scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 2d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

.claude/skills/checkpoint/SKILL.md · 55 lines

What it actually says

Checkpoint Skill

Save session state for clean handoff to the next session.

When to use

  • Context window is getting full (preemptively)
  • Before ending a session with work in progress
  • Before a long-running operation that might reset context

Protocol

1. Record current state in claude/tasks/todo.md

# Task: <current task title>
_Checkpointed: {{DATE}}_

**Goal:** <what done looks like>
**Branch:** <output of: git branch --show-current>
**Loaded docs:** claude/architecture.md, claude/rules.md, [others read this session]

## Completed Steps
- [x] 1. <step>
- [x] 2. <step>

## Remaining Steps
- [ ] 3. <next action — be specific>
- [ ] 4. <step>

## Next Action
> <Single most important thing to do when resuming>

## Uncommitted Files
<output of: git status --short | head -20>

## Notes
<Any constraints, blockers, or decisions made this session>

2. Update claude/tasks/lessons.md

If any corrections or new patterns were discovered this session, add them NOW.

3. Confirm to user

"Session state saved to claude/tasks/todo.md. To resume: use /resume."

Rules

  • NEVER checkpoint without writing the Next Action explicitly
  • NEVER skip lessons.md update if corrections were made
  • Checkpoint early — better to checkpoint too often than to lose context
Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 2d ago First seen · 55 lines · 39 tokens per session scan A 91ac030b740f

Subscribe to this mod's changes

checkpoint is a skill published in the GitHub repository brain-bootstrap/claude-code-brain-bootstrap (11 stars, last pushed 4mo ago), licensed MIT. It adds 39 tokens to every session and 377 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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