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 toolsdk-ai/toolsdk-mcp-registry --skill check-mcp-jsongit clone --depth 1 https://github.com/toolsdk-ai/toolsdk-mcp-registryWrote 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/toolsdk-ai/toolsdk-mcp-registry/check-mcp-json)<a href="https://agentmods.dev/skills/toolsdk-ai/toolsdk-mcp-registry/check-mcp-json"><img src="https://agentmods.dev/badge/skills/toolsdk-ai/toolsdk-mcp-registry/check-mcp-json/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/toolsdk-ai/toolsdk-mcp-registry/check-mcp-json"><img src="https://agentmods.dev/badge/skills/toolsdk-ai/toolsdk-mcp-registry/check-mcp-json.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 | $0.00068 | $0.01064 |
| Opus 5 | $0.00034 | $0.00532 |
| Sonnet 5 | $0.00014 | $0.00213 |
| Haiku 4.5 | $0.00007 | $0.00106 |
Grade A, and why
check-mcp-json 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 10d 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 — 115 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Check MCP JSON
Review registry contributions by validating their package JSON without installing, executing, or probing submitted MCP packages and services. The trusted registry validator is the merge gate.
Load Repository Rules
Read these files before acting:
AGENTS.mddocs/PR_REVIEW.mddocs/CONTRIBUTING.md
Repository instructions and the user's latest authorization override this skill.
Safety Boundaries
- Run the validator from a clean checkout whose
HEADequals the latest trusted base ref. - Never run scripts from a contributor branch.
- Never install or execute a submitted package. Do not run
make build,pnpm install, package lifecycle scripts, or a contributor-provided validation command. - Do not comment, close, edit, mark ready, or merge a PR until the user authorizes that action.
- Never use
--admin,--auto, or a merge method other than squash. - Review independent PRs in parallel. PRs with pairwise-disjoint changed paths and registry
identities may submit squash merges concurrently; retry GitHub's transient
Base branch was modifiedrejection after another merge lands. - Disable repository hooks for authorized commits and pushes with
-c core.hooksPath=/dev/null; hooks may run repository scripts unexpectedly.
Review Workflow
-
Refresh the trusted checkout:
git switch main git fetch origin main git pull --ff-only origin main -
Run the bundled read-only reviewer:
.agents/skills/check-mcp-json/scripts/review-pr.sh <pr-number>The script records PR state, lists changed files, creates a detached temporary worktree, and invokes the trusted validator against
origin/main. It does not execute contributor code. -
Inspect the complete diff with
gh pr diff <pr-number>. For registry submissions, require only package JSON files and reject unrelated workflow, dependency, generated output, workspace, or build changes. -
Classify the PR:
- Ready: scope, trusted validation, checks, and identity all pass.
- Simple authorized fix: metadata can be corrected without redesigning the submission.
- Comment and close: duplicate, invalid JSON, unrelated changes, or no registry-compatible representation.
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.
- 10d ago First seen · 115 lines · 68 tokens per session scan A fa52a5446120
check-mcp-json is a skill published in the GitHub repository toolsdk-ai/toolsdk-mcp-registry (187 stars, last pushed 14d ago), licensed MIT. It adds 68 tokens to every session and 1,064 once invoked, about $0.0003 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 2026-08-30.
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