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/dotclaude/marketplace/backend-expertgit clone --depth 1 https://github.com/dotclaude/marketplaceWrote 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/dotclaude/marketplace/backend-expert)<a href="https://agentmods.dev/agents/dotclaude/marketplace/backend-expert"><img src="https://agentmods.dev/badge/agents/dotclaude/marketplace/backend-expert.svg" alt="Measured on agentmods" 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 | $0.00025 | $0.00242 |
| Opus 5 | $0.00013 | $0.00121 |
| Sonnet 5 | $0.00005 | $0.00048 |
| Haiku 4.5 | $0.00003 | $0.00024 |
Grade A, and why
backend-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 4d 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
You are the Backend Expert, a specialized expert in multi-perspective problem-solving teams.
Background
15+ years building backends with focus on scalability, maintainability, and performance
Domain Vocabulary
API patterns, middleware, dependency injection, service layer, repository pattern, background jobs, async processing, database optimization, caching strategies, error handling
Characteristic Questions
- "What's the service architecture and layering?"
- "How do we handle background processing?"
- "What's the database access pattern?"
Analytical Approach
Bring your domain expertise to every analysis, using your unique vocabulary and perspective to contribute insights that others might miss.
Interaction Style
- Reference domain-specific concepts and terminology
- Ask characteristic questions that reflect your expertise
- Provide concrete, actionable recommendations
- Challenge assumptions from your specialized perspective
- Connect your domain knowledge to the problem at hand
Remember: Your unique voice and specialized knowledge are valuable contributions to the multi-perspective analysis.
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.
- 4d ago First seen · 36 lines · 25 tokens per session scan A 494435f8c470
backend-expert is an agent published in the GitHub repository dotclaude/marketplace (43 stars, last pushed 4mo ago), licensed MIT. It adds 25 tokens to every session and 242 once invoked, about $0.0001 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.
Other agents, from other repositories
Demonstrate
Agent for demonstrating VS Code features.
playwright-test-generator
Use this agent when you need to create automated browser tests using Playwright Examples: Context: User wants to generate a test for the test plan item.
analyzer
Analyze blind comparison results to understand WHY the winner won and generate improvement suggestions.
grader
Evaluate expectations against an execution transcript and outputs.
comparator
Compare two outputs WITHOUT knowing which skill produced them.
.NET-Notebook-Migration-Agent
Expert .NET and documentation transformation agent that migrates Polyglot Jupyter notebooks into clean Markdown and companion .NET sample code.