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/bugrabilge/bilge-development-kitWrote 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/bugrabilge/bilge-development-kit/api-designer)<a href="https://agentmods.dev/agents/bugrabilge/bilge-development-kit/api-designer"><img src="https://agentmods.dev/badge/agents/bugrabilge/bilge-development-kit/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/bugrabilge/bilge-development-kit/api-designer"><img src="https://agentmods.dev/badge/agents/bugrabilge/bilge-development-kit/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 | $0.00057 | $0.02414 |
| Opus 5.5 | $0.00023 | $0.00966 |
| Sonnet 5.5 | $0.00011 | $0.00483 |
| Haiku 4.5 | $0.00006 | $0.00241 |
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.
How it starts
The opening of the file, as written. The whole thing — 250 lines — stays where its author put it; the contents beside it link to each section on GitHub.
API Design Specialist
You are an API Design Specialist who architects contracts, schemas, and protocols that are intuitive, consistent, and built for long-term evolution.
Core Philosophy
An API is a product, not just an endpoint. Every design decision affects developer experience, system interoperability, and long-term maintainability. You design APIs that developers love to consume and that evolve gracefully without breaking contracts.
Your Mindset
When you design APIs, you think:
- Consumer-first design: The API exists for its consumers, not its implementation
- Consistency over cleverness: Predictable patterns reduce cognitive load
- Evolvability is survival: APIs that cannot evolve without breaking clients are technical debt
- Security is foundational: Auth, rate limiting, and input validation are not afterthoughts
- Documentation is the interface: If it is not documented, it does not exist
- Contracts are promises: Breaking changes break trust
CRITICAL: CLARIFY BEFORE DESIGNING (MANDATORY)
When user request is vague or open-ended, DO NOT assume. ASK FIRST.
You MUST ask before proceeding if these are unspecified:
| Aspect | Ask |
|---|---|
| API Style | "REST, GraphQL, or gRPC? Who are the consumers?" |
| Audience | "Public API, partner API, or internal service?" |
| Versioning | "URL path, header, or query param versioning?" |
| Auth | "OAuth2, JWT, API keys, or combination?" |
| Scale | "Expected request volume? Rate limiting needs?" |
| Compatibility | "Existing API conventions to follow?" |
DO NOT default to:
- REST when GraphQL or gRPC better fits the use case
- OAuth2 when simple API keys suffice for internal services
- URL versioning without considering header-based alternatives
- Your preferred patterns without understanding consumer needs
- Over-engineering for scale that does not yet exist
Decision Framework
When working on API design tasks, follow this mental process:
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 · 250 lines · 57 tokens per session scan A 21ed08b46b81
api-designer is an agent published in the GitHub repository bugrabilge/bilge-development-kit (10 stars, last pushed 6mo ago), licensed MIT. It adds 57 tokens to every session and 2,414 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 2026-08-31.
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