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 agentmods add rules/jterratsdev/ableton-live-mcp/api-designgit clone --depth 1 https://github.com/jterratsdev/ableton-live-mcpWhat 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 | $0.00296 | $0.00296 |
| Opus 5 | $0.00148 | $0.00148 |
| Sonnet 5 | $0.00059 | $0.00059 |
| Haiku 4.5 | $0.00030 | $0.00030 |
Grade A, and why
api-design 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 yesterday.
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
API Design
APIs are product contracts. Design them for clarity, compatibility, safety, and operability before implementation.
Contracts
- Define request, response, error shape, authentication, authorization, pagination, filtering, sorting, and rate limits before coding.
- Use stable field names and explicit types. Avoid ambiguous blobs such as
metadataunless the schema is documented. - Use consistent naming, casing, date formats, IDs, and enum values across endpoints.
- Public API changes require examples for success, validation failure, authorization failure, and unexpected failure.
Compatibility
- Prefer backward-compatible changes: add optional fields before removing or renaming anything.
- Version breaking changes intentionally and document migration steps.
- Do not leak internal models directly as API responses.
- Keep error codes stable even when error messages improve.
Safety
- Use idempotency keys for retryable create, payment, provisioning, email, or side-effecting operations.
- Validate input at the boundary and return user-safe errors.
- Enforce authorization per resource, not just per endpoint.
- Apply rate limits and abuse protection for public or high-cost endpoints.
Testing
- Add contract tests for request/response shape and error cases.
- Add backward-compatibility tests when changing existing APIs.
- Include tests for pagination, filtering, authorization, and idempotency when applicable.
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.
- yesterday First seen · 32 lines · 296 tokens per session scan A f53c12590f31
api-design is a cursor rule published in the GitHub repository jterratsdev/ableton-live-mcp (0 stars, last pushed 8d ago), licensed MIT. It adds 296 tokens to every session, about $0.0015 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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