A manual session checkpoint tool that saves the current work state for later continuation. It writes a combined handoff record and updates pointers that help a future session find it.

Use it before switching tasks, pausing long work, handling a context limit, or preparing a resume-ready handoff.

It preserves context before a pause or task switch without ending the current session or automatically clearing its context.

checkpoint — Skill for Claude Code by mishahanin

Install

Getting it into your agent

It runs from inside its repository, so the clone comes first — what it calls does not travel with the file alone.

Clone the repo

git clone --depth 1 https://github.com/mishahanin/heading-os

agentmods

npx agentmods add skills/mishahanin/heading-os/checkpoint

Made for: Claude Code.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

README.md

[![agentmods](https://agentmods.dev/badge/skills/mishahanin/heading-os/checkpoint.svg)](https://agentmods.dev/skills/mishahanin/heading-os/checkpoint)

Your own site

<a href="https://agentmods.dev/skills/mishahanin/heading-os/checkpoint"><img src="https://agentmods.dev/badge/skills/mishahanin/heading-os/checkpoint.svg" alt="Measured on agentmods" height="20"></a>

Per session 66 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 3,412 The whole file, excluding the scripts and references it only reads on demand.

Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe. Third-party audits

NVIDIA SkillSpector warn 7 Sept 2026

SkillSpector: 1 finding, up to high

These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →

high Memory Poisoning · line 303
Skill manipulates agent memory, state, or stored context. Memory corruption can alter personality, override safety rules, or cause unpredictable behavior.

Fix: Protect agent memory and state from modification by untrusted content. Use read-only memory for critical instructions and validate all state changes.

How audits are shown

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.

Model	Per session	Once invoked
Fable 5.1	$0.00066	$0.03412
Opus 5	$0.00033	$0.01706
Sonnet 5	$0.00013	$0.00682
Haiku 4.5	$0.00007	$0.00341

Measured 7d ago against content hash a78b51bfe5b2, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-07, 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 7d 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.

Origin

Copies of this mod

1 near-identical copy found in the catalogue:

checkpoint — 95% identical, 30 lines differ

.claude/skills/checkpoint/SKILL.md · 308 lines

How it starts

The opening of the file, as written. The whole thing — 308 lines — stays where its author put it; the contents beside it link to each section on GitHub.

/checkpoint

Save a manual session checkpoint without running /compact or clearing context.

What this does

Writes ONE combined handoff file to outputs/operations/handoff-archive/
Updates FOUR pointer files. This session's pair sits under .latest/{session-slug}/{summary.md,prompt.md}, which the SessionStart inject hook reads. The shared pair sits at .latest/{summary.md,prompt.md}, which /next reads as "the newest handoff in this workspace"
Does NOT run /compact
Does NOT clear the session
Does NOT continue implementation after writing - wait for the user to direct next action

When to use

Soft / hard checkpoint offer fired (Stop hook surfaced the context threshold)
About to switch to an unrelated task, want resume-ready snapshot
Mid-implementation, want to save state before risky action
Long session approaching natural pause point

Procedure

Step 0 - Handle a switch argument first

Split $ARGUMENTS on whitespace. If the FIRST token is exactly auto, exactly unattended, or exactly compact-at, this is a switch. It is not a checkpoint. Anything else is a note, including a word that merely begins with one of them. Match the whole token, never a prefix. compact-at takes the SECOND token as its value.

Run one of these, then stop. Do not write any file.

python scripts/checkpoint-paths.py --auto on
python scripts/checkpoint-paths.py --auto off
python scripts/checkpoint-paths.py --auto status
python scripts/checkpoint-paths.py --unattended on
python scripts/checkpoint-paths.py --unattended off
python scripts/checkpoint-paths.py --unattended status
python scripts/checkpoint-paths.py --compact-at 35
python scripts/checkpoint-paths.py --compact-at off
python scripts/checkpoint-paths.py --compact-at status

Report the command output in one line. For auto on, continue to Step 1 and write the checkpoint as well. The operator asked at a threshold and expects this one on disk. For unattended on, stop after the report. The operator is about to leave, so a question here defeats the switch.

Read the full file on GitHub · 308 lines

Files

What ships with it

2 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

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.

7d ago First seen · 308 lines · 66 tokens per session scan A a78b51bfe5b2

Subscribe to this mod's changes

checkpoint is a skill published in the GitHub repository mishahanin/heading-os (11 stars, last pushed yesterday), licensed Apache-2.0. It adds 66 tokens to every session and 3,412 once invoked, about $0.0003 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.

Claude Code LLM Memory and context Security ai-agent anthropic automation

agentsview-usage

Search prior session history to recall how similar work was handled before. Use when you want to leverage a past approach, check prior experience on a topic, answer "how was this handled before", or cross-verify current handling against precedent from earlier sessions.

josix/agent-flow · 55 tokens

letter-hooker

Erweitert automation-self-care um Letter Hooks, Preflight-Bootloader, Dokument-Traversierungsregeln und selbstheilende Prompt-Kontext- Anreicherung für KI-Agenten und CLIs ohne native, ereignisgetriebene JSON-Lifecycle-Hooks (wie Antigravity / Gemini CLI). Nutzen, wenn ein Agent Preflight-Regeln injizieren, vor…

ellmos-ai/skills · 129 tokens

checkpoint