signal-ckpt

signal-ckpt is a skill for Claude Code from mattbaconz/signal. It costs 80 tokens per session (1,402 once invoked), scanned A, original, MIT.

A manual command that compresses the current coding session into a very short checkpoint containing the project, progress, blockers, and next task.

In plain words
What is it for?
Use it when you type /signal-ckpt, ask to checkpoint or compress the session, or need to save a compact progress summary.
Why use it?
It keeps a long conversation from using too much context while preserving the information needed to continue the work.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin.

Part of the signal plugin — 8 skills shipped together

Good fit Use it when you type /signal-ckpt, ask to checkpoint or compress the session, or need to save a compact progress summary.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/mattbaconz/signal/signal-ckpt
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.

Any agent
npx skills add mattbaconz/signal --skill signal-ckpt
Clone the repo
git clone --depth 1 https://github.com/mattbaconz/signal

Made for: Claude Code.

Or install signal, the plugin that ships this one along with the rest of its 8 skills.

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.

agentmods badge for signal-ckpt

README.md
[![agentmods](https://agentmods.dev/badge/skills/mattbaconz/signal/signal-ckpt/github.svg)](https://agentmods.dev/skills/mattbaconz/signal/signal-ckpt)
Your own site
<a href="https://agentmods.dev/skills/mattbaconz/signal/signal-ckpt"><img src="https://agentmods.dev/badge/skills/mattbaconz/signal/signal-ckpt/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.

agentmods 80×15 button for signal-ckpt

Your own site · 80×15
<a href="https://agentmods.dev/skills/mattbaconz/signal/signal-ckpt"><img src="https://agentmods.dev/badge/skills/mattbaconz/signal/signal-ckpt.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 80 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,402 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 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 5.1 $0.00080 $0.01402
Opus 5 $0.00040 $0.00701
Sonnet 5 $0.00016 $0.00280
Haiku 4.5 $0.00008 $0.00140

Measured 12d ago against content hash f2c8d8099f1e, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-12, from the pricing page.

Security

Grade A, and why

signal-ckpt 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 12d 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-signal/skills/signal-ckpt/SKILL.md · 185 lines

How it starts

The opening of the file, as written. The whole thing — 185 lines — stays where its author put it; the contents beside it link to each section on GitHub.

⚡ signal-ckpt — Manual Checkpoint

Collapse the session into a ≤50 token state atom. Drop all prior history. Resume from the atom.


Invocation Triggers

Activate when user says any of:

  • /signal-ckpt
  • "checkpoint", "compress context", "summarize session"
  • "save state", "compress history", "ckpt"
  • Auto-fires in SIGNAL-3 mode every 5 turns

Output Format

CKPT[N]:
  §project={name} §stack={tech}
  progress=[{task}✓, {task}✗, {task}∅, {task}/]
  blockers=[{issue}⊥{component}]
  next={next_task}
  §decisions=[{decision}✓]

N = checkpoint sequence number, starting at 1. Increment on each checkpoint.

Minimal valid checkpoint (when session is simple):

CKPT[1]:
  §project=my-app
  progress=[auth✓, api/]
  next=finish api endpoints

Full checkpoint (active blockers, decisions, aliases):

CKPT[3]:
  §project=data-pipeline §stack=python+airflow
  [X1]=schema_validation_step [X2]=postgres_loader
  progress=[ingest✓, transform✓, X1✗, X2∅]
  blockers=[X1⊥schema_mismatch]
  next=fix schema_mismatch in X1
  §decisions=[use_upsert✓]

Hard Rules

  1. ≤50 tokens total. Count ruthlessly. If over, compress further: merge related tasks, abbreviate names, drop resolved items.

  2. Checkpoint replaces conversation history. After this fires, all prior turns can be dropped. The checkpoint IS the history.

  3. Only active blockers. Resolved blockers are gone. They do not appear anywhere in the checkpoint.

  4. Only future-relevant decisions. §decisions only includes decisions that affect work not yet complete. Past decisions with no forward implication are dropped.

  5. next is singular. One task. The most immediate pending action. Not a backlog.

  6. Carry active aliases forward. Any [Xn] aliases still in use must appear in the checkpoint. Aliases for resolved items are dropped.


Collapse Algorithm

When generating a checkpoint:

  1. Identify all tasks mentioned in the session. Assign each a status from its last known state ( / ).

Read the full file on GitHub · 185 lines

Files

What ships with it

1 file 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.

  1. 12d ago First seen · 185 lines · 80 tokens per session scan A f2c8d8099f1e

Subscribe to this mod's changes

signal-ckpt is a skill published in the GitHub repository mattbaconz/signal (10 stars, last pushed 2mo ago), licensed MIT. It adds 80 tokens to every session and 1,402 once invoked, about $0.0004 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.

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