A progress-saving skill for archiving findings and shortening old session logs. It can process previous sessions and record detected issues or missing information.

Checkpointing work, reviewing older sessions, recording issues, and preparing context for continued work.

It helps continue longer tasks without keeping every old session record in the active context.

checkpoint — Skill for Claude Code and Codex by moonxorsun: A progress-saving skill for archiving findings and shortening old…

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/moonxorsun/focus-claude-code/checkpoint

Any agent

npx skills add moonxorsun/focus-claude-code --skill checkpoint

Clone the repo

git clone --depth 1 https://github.com/moonxorsun/focus-claude-code

Made for: Claude Code, Codex.

Or install focus, the plugin that ships this one along with the rest of its 4 skills, 4 commands, 5 hooks.

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/moonxorsun/focus-claude-code/checkpoint.svg)](https://agentmods.dev/skills/moonxorsun/focus-claude-code/checkpoint)

Your own site

<a href="https://agentmods.dev/skills/moonxorsun/focus-claude-code/checkpoint"><img src="https://agentmods.dev/badge/skills/moonxorsun/focus-claude-code/checkpoint.svg" alt="Measured on agentmods" height="20"></a>

Per session 15 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 1,054 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.

Model	Per session	Once invoked
Fable 5	$0.00015	$0.01054
Opus 5	$0.00008	$0.00527
Sonnet 5	$0.00003	$0.00211
Haiku 4.5	$0.00002	$0.00105

Measured 3d ago against content hash 9ed0a94d18fa, 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 3d 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.

plugins/focus/skills/checkpoint/SKILL.md · 149 lines

How it starts

The opening of the file, as written. The whole thing — 149 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Environment

Variable	Default
`CLAUDE_FOCUS_DIR`	`.claude/tmp/focus`

Use $CLAUDE_FOCUS_DIR in paths. If unset, use the default .claude/tmp/focus.

Checkpoint Workflow

Execute this workflow when user invokes /focus:checkpoint.

Step 1: Choose Processing Mode

Ask user which mode to use:

Mode	Description
Silent	Process all old sessions automatically
Interactive	Process only the oldest session, then pause
Oldest	Alias for Interactive

Step 2: Run Checkpoint Script

python "{{FOCUS_PLUGIN_ROOT}}/scripts/checkpoint_session.py" --mode=<mode> [--dry-run]

Options:

--mode=silent - Process all old sessions
--mode=interactive - Process only oldest session
--mode=oldest - Same as interactive
--dry-run - Show what would be done without modifying files

What the script does:

Processes sessions from old to new (skips current session)
Error detection → writes to pending_issues.md
Omission detection → calls Haiku API to find unrecorded information
Removes processed session records from operations.jsonl

Step 3: Handle Omission Detection Results

The script outputs omission detection results like:

### Session abc12345...
[Issue] Some bug that wasn't recorded
[Decision] A decision that was made but not documented
[Finding] An insight that was discovered

For each item:

[Issue] → Add to the appropriate section in focus_context.md
[Decision] → Add to the appropriate section in focus_context.md
[Finding] → Add to the appropriate section in focus_context.md
NONE or ERROR → No action needed

Step 4: Review Pending Issues

If pending_issues.md has items:

Read .claude/tmp/focus/pending_issues.md
For each issue, decide:
- Archive: If it reveals a pattern → use /focus:done when session completes
- Discard: If it's a user rejection or transient error

Read the full file on GitHub · 149 lines

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.

3d ago First seen · 149 lines · 15 tokens per session scan A 9ed0a94d18fa

Subscribe to this mod's changes

checkpoint is a skill published in the GitHub repository moonxorsun/focus-claude-code (5 stars, last pushed 6mo ago), licensed MIT. It adds 15 tokens to every session and 1,054 once invoked, about $0.0001 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 2026-08-31.

systematic-debugging

Use when encountering any bug, test failure, or unexpected behavior, before proposing fixes.

obra/superpowers · 21 tokens

brainstorming

You MUST use this before any creative work - creating features, building components, adding functionality, or modifying behavior. Explores user intent, requirements and design before implementation.

obra/superpowers · 37 tokens

auto-perf-optimize

Run agent-driven VS Code performance or memory investigations. Use when asked to launch Code OSS, automate a VS Code scenario, run the Chat memory smoke runner, capture renderer heap snapshots, take workflow screenshots, compare run summaries, or drive a repeatable scenario before heap-snapshot analysis.

microsoft/vscode · 62 tokens

chat-perf

Run chat perf benchmarks and memory leak checks against the local dev build or any published VS Code version. Use when investigating chat rendering regressions, validating perf-sensitive changes to chat UI, or checking for memory leaks in the chat response pipeline.

microsoft/vscode · 51 tokens

chat-pet-sprite-creation

Use when creating or changing VS Code chat pet sprite art, sprite sheets, state animations, eye treatments, Stable/Insiders variants, or pet transitions under src/vs/workbench/contrib/chat/browser/widget/media/chatPet.

microsoft/vscode · 53 tokens

cpu-profile-analysis

Analyze V8/Chrome CPU profiles (.cpuprofile) and DevTools trace files (Trace-.json). Use when: profiling performance, investigating slow functions, comparing code paths, finding bottlenecks, analyzing timeToRequest, understanding call trees from sampling profiler data, analyzing layout/paint/rendering, investigating…

microsoft/vscode · 71 tokens