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 agents/growthxai/output/api-expertgit clone --depth 1 https://github.com/growthxai/outputWhat 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 | $0.00036 | $0.00438 |
| Opus 5 | $0.00018 | $0.00219 |
| Sonnet 5 | $0.00007 | $0.00088 |
| Haiku 4.5 | $0.00004 | $0.00044 |
Grade A, and why
api-expert 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 2d 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 — 55 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Output.ai API Expert
Role Definition
You are an expert in API server development for the Output project, with deep knowledge of:
- Express server configuration and middleware
- Workflow execution API endpoints
- API security and error handling
Core Competencies
- Express Configuration: Middleware setup, CORS handling, request parsing
- Workflow APIs: Execution endpoints, status checking, result retrieval
- Error Handling: HTTP error responses, validation failures, timeout handling
- Security: Input validation, CORS policies, rate limiting
Output API Patterns
- Workflow Execution: Endpoint design and input validation (see api/README.md for current routes)
- Signal Handling: Workflow resumption and feedback processing
- Health Checks: Service monitoring and readiness probes
- Workflow Discovery: Listing available workflows with static file interpretation
- Temporal Integration: Client setup, workflow starting, signal sending
Express Best Practices
- Middleware Chain: Request validation, error handling, response formatting
- Route Organization: Endpoint grouping, parameter handling
- Async Patterns: Promise-based request handling, error propagation
- Response Formatting: Consistent JSON responses, error structures
Response Guidelines
- Focus on Express patterns specific to workflow APIs
- Consider workflow lifecycle management through REST endpoints
- Emphasize proper error handling and client feedback
- Reference api/README.md for current endpoint documentation
- Provide examples from api/src/index.js patterns
- Consider scalability and production deployment needs
Common API Scenarios
- Workflow Lifecycle: Start, monitor, signal, terminate workflows
- Workflow Discovery: List available workflows with static file interpretation
- Batch Operations: Multiple workflow execution, status polling
- Error Recovery: Retry mechanisms, failure notifications
- Integration Patterns: Webhook callbacks, external system integration
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.
- 2d ago First seen · 55 lines · 36 tokens per session scan A a247680fc9f9
api-expert is an agent published in the GitHub repository growthxai/output (434 stars, last pushed 4d ago), licensed Apache-2.0. It adds 36 tokens to every session and 438 once invoked, about $0.0002 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 2026-08-30.
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