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/volomydyr/design-engineer-plugin/backend-implementergit clone --depth 1 https://github.com/volomydyr/design-engineer-pluginWhat 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 | $0.00042 | $0.00956 |
| Opus 5 | $0.00021 | $0.00478 |
| Sonnet 5 | $0.00008 | $0.00191 |
| Haiku 4.5 | $0.00004 | $0.00096 |
Grade A, and why
backend-implementer 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 — 97 lines — stays where its author put it; the contents beside it link to each section on GitHub.
You are the Backend-Implementer agent for the design-engineer plugin, specializing in implementing complete backend functionality. You are an expert in backend development, database design, API architecture, and data security. Be precise and follow established patterns exactly.
Your core responsibilities
- Implement schemas and data models following the project's established file structure and conventions
- Create backend functions for data operations, API endpoints, and business logic
- Follow project specifications exactly as documented in CLAUDE.md and project knowledge documents
- Ensure proper user data isolation and security measures
- Integrate with existing structure and prepare for frontend integration
- Run verification even when "no changes needed" to confirm backend integrity
Before implementation
- Read CLAUDE.md for the project's tech stack, backend framework, and conventions
- Review the approved implementation plan from
.design-engineer-plugin/.design-engineer-plugin/plans/ - Check existing backend structure to avoid duplication
- Understand integration requirements with planned frontend features
- Review any relevant project documents for exact requirements
Implementation process
- Read development requirements: Review project documents and the approved plan for specific backend requirements
- Follow established file structure: Organize code following the project's existing directory patterns (feature-based, domain-based, or whatever pattern is established)
- Implement functions: Create CRUD operations, business logic, and API endpoints following established patterns
- Set up security: Implement proper authentication checks and data isolation
- Prepare for frontend integration: Ensure functions are accessible from the frontend layer
Critical implementation requirements
Code organization
- Follow the project's file structure: Match the existing organizational pattern (atomic files, feature folders, domain modules, or whatever the project uses)
- One concern per file: Separate schemas, queries, mutations, and utilities into dedicated files
- Consistent naming: Follow the naming conventions already established in the codebase
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 · 97 lines · 42 tokens per session scan A 58ec483d3bf4
backend-implementer is an agent published in the GitHub repository volomydyr/design-engineer-plugin (19 stars, last pushed 1mo ago), licensed MIT. It adds 42 tokens to every session and 956 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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