Borrowing it
Nothing to install: this file belongs to SioYooo/RepoGrammar. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/SioYooo/RepoGrammar/main/.agents/skills/mcp-contract-change/SKILL.mdgit clone --depth 1 https://github.com/SioYooo/RepoGrammarWrote 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/sioyooo/repogrammar/mcp-contract-change)<a href="https://agentmods.dev/skills/sioyooo/repogrammar/mcp-contract-change"><img src="https://agentmods.dev/badge/skills/sioyooo/repogrammar/mcp-contract-change/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/sioyooo/repogrammar/mcp-contract-change"><img src="https://agentmods.dev/badge/skills/sioyooo/repogrammar/mcp-contract-change.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 | $0.00028 | $0.00369 |
| Opus 5.5 | $0.00011 | $0.00148 |
| Sonnet 5.5 | $0.00006 | $0.00074 |
| Haiku 4.5 | $0.00003 | $0.00037 |
Grade A, and why
mcp-contract-change 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 2mo 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
Purpose
Protect the MCP contract while keeping transport concerns out of the domain model.
Trigger conditions
Use when changing src/rust/interfaces/mcp/, planned MCP tools, transport-neutral
contract types, serialization behavior, or documented MCP error semantics.
Required reading
docs/specifications/mcp-api.mddocs/architecture/dependency-rules.mddocs/development/branching-and-commits.md
Preconditions
- Decide whether the change is a major feature.
- Confirm no MCP SDK type leaks into
core. - Preserve the default minimal MCP surface unless an ADR changes it:
repogrammar_contextwith explicit operations rather than multiple default pattern-family tools.
Step-by-step procedure
- Update the MCP specification first.
- Keep domain and transport types separated.
- Add serialization and deserialization tests when concrete schemas exist.
- Analyze compatibility with existing tool names and responses.
- Update CHANGELOG for user-visible contract changes.
- Add or update an ADR for breaking or durable contract decisions.
Required verification
Run formatting, clippy, tests, repository guard, and guide equality checks.
Documentation updates
Update docs/specifications/mcp-api.md, README, CHANGELOG, and ADRs as needed.
Commit requirements
Use a major-feature branch for breaking or user-visible MCP changes.
Completion report
Report changed tools, compatibility impact, tests, branch cleanup status when merged, and any deferred schema work.
Failure and rollback handling
If compatibility cannot be proven, mark the contract unstable and do not claim a stable MCP API.
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.
- 2mo ago First seen · 60 lines · 28 tokens per session scan A de3fb01f6ecb
mcp-contract-change is a skill published in the GitHub repository SioYooo/RepoGrammar (0 stars, last pushed yesterday), licensed MIT. It adds 28 tokens to every session and 369 once invoked, about $0.0001 per session on Opus 5.5. 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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