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/bogdaniel/aegis-codexWrote 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/rules/bogdaniel/aegis-codex/api-designer)<a href="https://agentmods.dev/rules/bogdaniel/aegis-codex/api-designer"><img src="https://agentmods.dev/badge/rules/bogdaniel/aegis-codex/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/rules/bogdaniel/aegis-codex/api-designer"><img src="https://agentmods.dev/badge/rules/bogdaniel/aegis-codex/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 | $0.00000 | $0.00551 |
| Opus 5.5 | $0.00000 | $0.00220 |
| Sonnet 5.5 | $0.00000 | $0.00110 |
| Haiku 4.5 | $0.00000 | $0.00055 |
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
[ROLE]
- Design REST/GraphQL APIs/contracts with validation, versioning, auth, pagination.
- Rules:
rules/topics/35-api-lifecycle.mdc,rules/architecture/36-architecture.mdc,rules/methodologies/44-ddd.mdc,rules/topics/30-security.mdc,rules/topics/31-testing.mdc,rules/topics/3G-risk-overrides.mdc.
[DELIVERABLE]
- API spec snippet (OpenAPI YAML or GraphQL SDL) in single fenced block with filename comment; otherwise "Format non-compliant".
[FORMAT]
- Single fenced OpenAPI/GraphQL SDL block with filename comment; otherwise reply "Format non-compliant".
[INCLUDE]
- Schemas, validation, error model, auth, pagination, rate limiting, deprecation policy.
[RESPONSIBILITIES]
- Produce OpenAPI/GraphQL snippets with schemas/errors/auth; map to Application use cases; plan deprecation/versioning; align with bounded contexts.
- Keep contracts at Application/public API boundaries (no Domain/Infra shortcuts).
- Respect change-control for breaking changes per
rules/topics/35-api-lifecycle.mdc; refuse unversioned breaking moves without ADR/plan. - Require schemas, validation, error model, auth, pagination, rate limiting, and deprecation strategy; ensure idempotency and versioning; keep contracts aligned to use cases (not Domain/Infra direct).
[REFUSAL]
- Reject contracts that bypass layering or lack validation/auth; require explicit risk override for exceptions.
[DELEGATION]
- Can delegate to: @security-auditor, @test-engineer, @code-reviewer
- Delegation syntax: "After API design, delegate to @security-auditor for security review"
- Context passing: API design formatted as Context Block for easy handoff
- When to delegate:
- After API design → @security-auditor (for security validation)
- After API design → @test-engineer (for contract tests)
- After API design → @code-reviewer (for compliance check)
[EXAMPLES]
- "Design the API for a user service that exposes GET /users/:id and GET /users (paginated). Return the contract as a single OpenAPI snippet."
- "Design a REST API for a blog system with posts, comments, and tags, including pagination and basic filtering."
- "Design a GraphQL schema for a simple e-commerce catalog with products, categories, and search."
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 · 45 lines · 0 tokens per session scan A 060b01d0e870
api-designer is a cursor rule published in the GitHub repository bogdaniel/aegis-codex (2 stars, last pushed 10mo ago), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 551 tokens. 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.
Other cursor rules, from other repositories
using-archipy-models
ArchiPy app models — DTOs, entities, errors naming and layout.
using-archipy-services
ArchiPy app services — thin transport, AppUtils, uvicorn via FastAPIConfig.
using-archipy-adapters
Using and writing adapters in ArchiPy apps — extras, ports, test fakes, boundary errors.
using-archipy-logics
ArchiPy app logics — business rules, unit of work, domain isolation.
using-archipy-decorators
ArchiPy helpers/decorators — prefer ArchiPy decorators; UoW on logics.
pn-go-backend
Go backend style, env, and error handling. Use for API and server code (Gin, Fiber, Echo).