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.
npx skills add monkilabs/opencastle --skill session-checkpointsgit clone --depth 1 https://github.com/monkilabs/opencastleWrote 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.
[](https://agentmods.dev/skills/monkilabs/opencastle/session-checkpoints)<a href="https://agentmods.dev/skills/monkilabs/opencastle/session-checkpoints"><img src="https://agentmods.dev/badge/skills/monkilabs/opencastle/session-checkpoints/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.
<a href="https://agentmods.dev/skills/monkilabs/opencastle/session-checkpoints"><img src="https://agentmods.dev/badge/skills/monkilabs/opencastle/session-checkpoints.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector pass
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 | $0.00043 | $0.00380 |
| Opus 5 | $0.00022 | $0.00190 |
| Sonnet 5 | $0.00009 | $0.00076 |
| Haiku 4.5 | $0.00004 | $0.00038 |
Grade A, and why
session-checkpoints 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 5d 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.
What it actually says
Skill: Session Checkpoints
When to Checkpoint
| Trigger | Action |
|---|---|
| Before first delegation | After decomposition, before agents start |
| After each phase | When a parallel batch completes |
| Before risky work | DB migrations, large refactors, security changes |
| Session end | Any session with incomplete work |
| Context running low | Checkpoint immediately |
Phase boundaries that warrant a checkpoint: load the decomposition skill.
Creating a Checkpoint
- Write
.opencastle/SESSION-CHECKPOINT.mdfrom the canonical CHECKPOINT-TEMPLATE.md. - Commit it or save to workspace; attach to the tracker issue.
- Verify:
cat .opencastle/SESSION-CHECKPOINT.md; confirm listed files exist.
Resuming
- Read
.opencastle/SESSION-CHECKPOINT.md - Run
git status,git branch— confirm you are on correct branch - Check In Progress tasks — if stale (>1 session old), verify files match expected state
- Check Pending Approvals — remove rows for questions the user has since answered in chat
- Read tracker issues for tasks marked In Progress or Todo
- Follow Resume Instructions section in checkpoint
- Update checkpoint progress after each completed task
If checkpoint missing or corrupt: Rebuild from git log --oneline -20, tracker state.
Cleanup & Team Lead
When all issues Done: archive to tracker; delete .opencastle/SESSION-CHECKPOINT.md.
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.
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.
- 5d ago First seen · 41 lines · 43 tokens per session scan A 8be072054a6d
session-checkpoints is a skill published in the GitHub repository monkilabs/opencastle (61 stars, last pushed 11d ago), licensed MIT. It adds 43 tokens to every session and 380 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 2026-09-03.
Other skills, from other repositories
jira-ticket-builder
Turns rough input into structured Jira work. Two modes — single-ticket mode turns a bug description, meeting notes, Slack thread, incident writeup, or a few sentences into one fully-structured Jira ticket; decomposition mode turns a rough requirements doc or product brief with multiple asks and open questions into…
linear
Read Linear issues, transition state, and post comments. The entry point for ticket-driven agent workflows.
product-architect
Complete product development system with 80 agents and 36 frameworks. Use when the user wants to build a product, write a PRD, plan an MVP or roadmap, design an app, research a market or check whether a feature already exists or is novel, do competitive analysis, run a security audit, build a financial model, plan…
tsk-add
Queue a single task based on the current conversation using tsk add.
tsk-help
Use this skill when the user asks about tsk commands, delegating development tasks to AI agents, managing sandboxed task execution, or working with the tsk task queue and server.
salesforce-live-change-approval-protocol
Use this skill when any proposed mutation to a live Salesforce production org must be evaluated before execution. This is a refusal-by-default gate: if any required precondition is missing, the skill stops and refuses. Required preconditions are targetorgidentity, environmenttype, useridentity, permissionscope…