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.
/plugin marketplace add asfbay-bit/opchain-skills/plugin install opchainWrote 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/asfbay-bit/opchain-skills/oc-checkpoint-protocol)<a href="https://agentmods.dev/skills/asfbay-bit/opchain-skills/oc-checkpoint-protocol"><img src="https://agentmods.dev/badge/skills/asfbay-bit/opchain-skills/oc-checkpoint-protocol/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/asfbay-bit/opchain-skills/oc-checkpoint-protocol"><img src="https://agentmods.dev/badge/skills/asfbay-bit/opchain-skills/oc-checkpoint-protocol.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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 | $0.00034 | $0.08698 |
| Opus 5 | $0.00017 | $0.04349 |
| Sonnet 5 | $0.00007 | $0.01740 |
| Haiku 4.5 | $0.00003 | $0.00870 |
Grade A, and why
oc-checkpoint-protocol 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 6d 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.
How it starts
The opening of the file, as written. The whole thing — 729 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Checkpoint Protocol
A cross-skill convention for session persistence. Any skill that runs multi-step workflows across conversations adopts this protocol to save, resume, and recover state without the user re-explaining context.
This is a protocol, not a skill. It defines a file format, naming convention, resume behavior, and integration contract that individual skills implement. Think of it like HTTP — the spec lives here, the implementations live in each skill.
Two versions, don't confuse them
protocol_version— the on-disk schema version, currently"1.1". It lives inside every checkpoint file and only changes when the file shape grows in a way the validator must know about. The validator (scripts/checkpoint.mjs) enforces it and accepts both"1.0"and"1.1".- Skill release version — the
versionin this file's YAML frontmatter. It tracks the evolution of the docs and tooling (thepm_refsextension, thedoctor/nextcommands, etc.) and moves independently, in lockstep with the rest of the catalog. oc-release-ops bumps it.
Additive fields, two ways to ship them. An optional additive field can ride
under the same wire version — pm_refs (skill release 1.2) was added under
schema "1.0" with no wire bump, because old checkpoints stayed valid and the
shape only grew. OR a release can group additive fields into a marked minor
wire bump when it wants a visible protocol revision. v1.6 ("the instrumented
pipeline") took the second path: cost, eval_scores, and telemetry_handle
landed together as wire "1.1". It is still fully backward compatible —
"1.0" checkpoints validate unchanged, those three fields stay optional — the
1.1 stamp just marks the revision. New writes stamp "1.1"; oc-migration-ops
sweeps existing "1.0" files forward. A wire bump is never a breaking change
here: it only ever adds optional fields, never removes or repurposes one.
Problem Statement
Claude's context resets between conversations. Multi-step skills (oc-app-architect, tri-dev, oc-reverse-spec, oc-stack-forge, oc-code-auditor, oc-deploy-ops, oc-git-ops) lose all progress when a session ends. Today:
What ships with it
3 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.
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.
- 6d ago Changed 18e76a217f8a
- 9d ago First seen · 729 lines · 34 tokens per session scan A eaefadcc8705
oc-checkpoint-protocol is a skill published in the GitHub repository asfbay-bit/opchain-skills (0 stars, last pushed 5d ago), licensed Apache-2.0. It adds 34 tokens to every session and 8,698 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 2026-08-31.
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