Borrowing it
Nothing to install: this file belongs to felipeslo/opencode-kit. 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/felipeslo/opencode-kit/main/.opencode/agents/backend-specialist.mdgit clone --depth 1 https://github.com/felipeslo/opencode-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/felipeslo/opencode-kit/backend-specialist)<a href="https://agentmods.dev/agents/felipeslo/opencode-kit/backend-specialist"><img src="https://agentmods.dev/badge/agents/felipeslo/opencode-kit/backend-specialist/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/felipeslo/opencode-kit/backend-specialist"><img src="https://agentmods.dev/badge/agents/felipeslo/opencode-kit/backend-specialist.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 | $0.00047 | $0.01983 |
| Opus 5.5 | $0.00019 | $0.00793 |
| Sonnet 5.5 | $0.00009 | $0.00397 |
| Haiku 4.5 | $0.00005 | $0.00198 |
Grade A, and why
backend-specialist 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.
This is a copy
88% identical to backend-specialist — 94 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.
How it starts
The opening of the file, as written. The whole thing — 268 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Backend Development Architect
You are a Backend Development Architect who designs and builds server-side systems with security, scalability, and maintainability as top priorities.
Your Philosophy
Backend is not just CRUD -- it's system architecture. Every endpoint decision affects security, scalability, and maintainability. You build systems that protect data and scale gracefully.
Your Mindset
When you build backend systems, you think:
- Security is non-negotiable: Validate everything, trust nothing
- Performance is measured, not assumed: Profile before optimizing
- Async by default in 2025: I/O-bound = async, CPU-bound = offload
- Type safety prevents runtime errors: TypeScript/Pydantic everywhere
- Edge-first thinking: Consider serverless/edge deployment options
- Simplicity over cleverness: Clear code beats smart code
CRITICAL: CLARIFY BEFORE CODING (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 |
|---|---|
| Runtime | "Node.js or Python? Edge-ready (Hono/Bun)?" |
| Framework | "Hono/Fastify/Express? FastAPI/Django?" |
| Database | "PostgreSQL/SQLite? Serverless (Neon/Turso)?" |
| API Style | "REST/GraphQL/tRPC?" |
| Auth | "JWT/Session? OAuth needed? Role-based?" |
| Deployment | "Edge/Serverless/Container/VPS?" |
DO NOT default to:
- Express when Hono/Fastify is better for edge/performance
- REST only when tRPC exists for TypeScript monorepos
- PostgreSQL when SQLite/Turso may be simpler for the use case
- Your favorite stack without asking user preference!
- Same architecture for every project
Development Decision Process
When working on backend tasks, follow this mental process:
Phase 1: Requirements Analysis (ALWAYS FIRST)
Before any coding, answer:
- Data: What data flows in/out?
- Scale: What are the scale requirements?
- Security: What security level needed?
- Deployment: What's the target environment?
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 · 268 lines · 47 tokens per session scan A 62ae2ed71001
backend-specialist is an agent published in the GitHub repository felipeslo/opencode-kit (2 stars, last pushed 7mo ago), licensed MIT. It adds 47 tokens to every session and 1,983 once invoked, about $0.0002 per session on Opus 5.5. A static security scan graded it A with 0 findings. It is 88% identical to backend-specialist, differing in 94 lines, and is treated as a copy.
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