A manual session checkpoint that saves the current work state for later continuation. It writes a combined handoff record and updates pointer files used to resume the workspace.

Use it before pausing, switching tasks or taking a risky step. It is intended for explicit checkpoint requests and saves the handoff under the workspace's operations archive.

It prevents important context from being lost during a long session or task switch. It records where work stands without clearing the current session or continuing implementation.

checkpoint — Skill for Claude Code by mishahanin

Install

Getting it into your agent

This one installs as part of its plugin. Adding the marketplace and installing the plugin brings it with everything else the plugin ships.

Claude Code

/plugin marketplace add mishahanin/heading-os-marketplace

Claude Code

/plugin install heading-core

Made for: Claude Code.

Or install heading-core, the plugin that ships this one along with the rest of its 3 skills, 2 commands.

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-marketplace/checkpoint/github.svg)](https://agentmods.dev/skills/mishahanin/heading-os-marketplace/checkpoint)

Your own site

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

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

Your own site · 80×15

<a href="https://agentmods.dev/skills/mishahanin/heading-os-marketplace/checkpoint"><img src="https://agentmods.dev/badge/skills/mishahanin/heading-os-marketplace/checkpoint.svg" alt="Reviewed on agentmods" width="80" 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 3,542 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.

Origin 95% copy Near-identical to another mod 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	$0.03542
Opus 5	$0.00033	$0.01771
Sonnet 5	$0.00013	$0.00708
Haiku 4.5	$0.00007	$0.00354

Measured 11d ago against content hash c88ba27c4641, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, 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 11d 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

This is a copy

95% identical to checkpoint — 30 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

plugins/heading-core/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 "${CLAUDE_PLUGIN_ROOT}"/scripts/checkpoint-paths.py --auto on
python "${CLAUDE_PLUGIN_ROOT}"/scripts/checkpoint-paths.py --auto off
python "${CLAUDE_PLUGIN_ROOT}"/scripts/checkpoint-paths.py --auto status
python "${CLAUDE_PLUGIN_ROOT}"/scripts/checkpoint-paths.py --unattended on
python "${CLAUDE_PLUGIN_ROOT}"/scripts/checkpoint-paths.py --unattended off
python "${CLAUDE_PLUGIN_ROOT}"/scripts/checkpoint-paths.py --unattended status
python "${CLAUDE_PLUGIN_ROOT}"/scripts/checkpoint-paths.py --compact-at 35
python "${CLAUDE_PLUGIN_ROOT}"/scripts/checkpoint-paths.py --compact-at off
python "${CLAUDE_PLUGIN_ROOT}"/scripts/checkpoint-paths.py --compact-at status

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.

11d ago First seen · 308 lines · 66 tokens per session scan A c88ba27c4641

Subscribe to this mod's changes

checkpoint is a skill published in the GitHub repository mishahanin/heading-os-marketplace (2 stars, last pushed 4d ago), licensed Apache-2.0. It adds 66 tokens to every session and 3,542 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 0 findings. It is 95% identical to checkpoint, differing in 30 lines, and is treated as a copy.

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