Borrowing it
Nothing to install: this file belongs to popoloni/non_deterministic_sw_eng. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/popoloni/non_deterministic_sw_eng/main/04-context-engineering/copilot-instructions/.github/instructions/api.instructions.mdgit clone --depth 1 https://github.com/popoloni/non_deterministic_sw_engWrote 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/instructions/popoloni/non_deterministic_sw_eng/api)<a href="https://agentmods.dev/instructions/popoloni/non_deterministic_sw_eng/api"><img src="https://agentmods.dev/badge/instructions/popoloni/non_deterministic_sw_eng/api/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/instructions/popoloni/non_deterministic_sw_eng/api"><img src="https://agentmods.dev/badge/instructions/popoloni/non_deterministic_sw_eng/api.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 | $0.00184 | $0.00184 |
| Opus 5.5 | $0.00074 | $0.00074 |
| Sonnet 5.5 | $0.00037 | $0.00037 |
| Haiku 4.5 | $0.00018 | $0.00018 |
Grade A, and why
non_deterministic_sw_eng api.instructions.md 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
API Development Guidelines
When working with API endpoints in this project:
Validation
- Use zod schemas for all request validation
- Validate at the route level, not in business logic
- Return 400 for validation errors with details
Response Format
// Success response
{ data: T, meta?: { page, total } }
// Error response
{ error: { code: string, message: string, details?: unknown } }
Authentication
- All routes require auth by default
- Use
@publicdecorator for public routes - Access user via
req.userafter auth middleware
Error Handling
- Use
ApplicationErrorfor expected errors - Let unexpected errors bubble to global handler
- Log errors with request context
Reference
See src/api/users/ for canonical implementation.
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 · 35 lines · 184 tokens per session scan A eb299d655376
non_deterministic_sw_eng api.instructions.md is an instructions file published in the GitHub repository popoloni/non_deterministic_sw_eng (7 stars, last pushed 10mo ago), licensed MIT. It adds 184 tokens to every session, about $0.0007 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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