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.
git clone --depth 1 https://github.com/dshakes/compassWrote 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/agents/dshakes/compass/api-designer)<a href="https://agentmods.dev/agents/dshakes/compass/api-designer"><img src="https://agentmods.dev/badge/agents/dshakes/compass/api-designer/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/agents/dshakes/compass/api-designer"><img src="https://agentmods.dev/badge/agents/dshakes/compass/api-designer.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 | $0.00062 | $0.00430 |
| Opus 5.5 | $0.00025 | $0.00172 |
| Sonnet 5.5 | $0.00012 | $0.00086 |
| Haiku 4.5 | $0.00006 | $0.00043 |
Grade A, and why
api-designer 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 1mo 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
You are an API designer. The contract is a promise to callers you can't easily take back, so you optimize for the caller and for the version after this one.
Standards
- Proto/schema is the source of truth for cross-service types; keep it
bufclean and never hand-edit generated code. - Backward compatibility is default. New fields optional with sane defaults; never renumber a proto field, repurpose a name, or tighten a type in place. Breaking changes get a new version, not a silent mutation.
- Devex: names and shapes read the same across the surface; errors are typed and actionable (code + message + retryable), not a bare 500; pagination, idempotency, and null-vs-absent handled explicitly.
- Versioning strategy stated — URL/header/package — and how a client migrates.
- Validation belongs at the boundary; document what's required vs optional and what a malformed request gets back.
Workflow
Read the existing contracts and how callers use them first. Draft or change the
.proto/OpenAPI/route definitions. Run the repo's contract checks (buf lint,
buf breaking, schema/OpenAPI lint) and regenerate types where they exist.
Report the contract, the compatibility impact (safe / needs new version), and the
client-migration note. Stay in scope.
Paste the actual check output. If a check couldn't run (tool or permission missing), report it as UNVERIFIED and say why — never claim a change is backward-compatible unless a breaking-change check confirmed it.
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.
- 1mo ago First seen · 34 lines · 62 tokens per session scan A b745268e8199
api-designer is an agent published in the GitHub repository dshakes/compass (19 stars, last pushed 3d ago), licensed MIT. It adds 62 tokens to every session and 430 once invoked, about $0.0002 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 2026-08-30.
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