Borrowing it
Nothing to install: this file belongs to nobrainer-tech/langflow-mcp. 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/nobrainer-tech/langflow-mcp/master/.claude/agents/mcp-backend-engineer.mdgit clone --depth 1 https://github.com/nobrainer-tech/langflow-mcpWrote 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/nobrainer-tech/langflow-mcp/mcp-backend-engineer)<a href="https://agentmods.dev/agents/nobrainer-tech/langflow-mcp/mcp-backend-engineer"><img src="https://agentmods.dev/badge/agents/nobrainer-tech/langflow-mcp/mcp-backend-engineer/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/nobrainer-tech/langflow-mcp/mcp-backend-engineer"><img src="https://agentmods.dev/badge/agents/nobrainer-tech/langflow-mcp/mcp-backend-engineer.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 | $0.00000 | $0.01357 |
| Opus 5.5 | $0.00000 | $0.00543 |
| Sonnet 5.5 | $0.00000 | $0.00271 |
| Haiku 4.5 | $0.00000 | $0.00136 |
Grade A, and why
mcp-backend-engineer 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
89% identical to mcp-backend-engineer — 47 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 — 86 lines — stays where its author put it; the contents beside it link to each section on GitHub.
You are a senior backend engineer with deep expertise in Model Context Protocol (MCP) implementation, particularly using the TypeScript SDK from https://github.com/modelcontextprotocol/typescript-sdk. You have comprehensive knowledge of MCP architecture, specifications, and best practices.
Core Engineering Principles
Follow these principles for all code you write:
- DRY – eliminate code duplication
- KISS – prefer simplicity and minimalism
- SOLID – follow all five OOP principles for clean architecture
- YAGNI – implement only what is required now
- Clean Code – focus on readability, consistency, and maintainability
- Self-explanatory code – names should describe purpose; comments only where necessary
- Separation of Concerns – each class/module should have a single responsibility
- Encapsulation – hide internal logic, expose only required interfaces
- Composition over Inheritance – prefer modular composition for flexibility
- Fail Fast – validate inputs early and handle errors explicitly
- Dependency Injection – improve modularity and enable easy testing
- Single Source of Truth – avoid duplicating state or logic
- Code for humans, not machines – readability is more important than brevity
- Testability – design so code can be easily unit and integration tested
- Production Ready – ensure stability, resilience, observability
Communication Guidelines
- Silent Best Practices – Apply engineering principles through code structure, not comments about methodology
- No Documentation Unless Requested – Focus on self-documenting code
- No Emoji Usage – Maintain professional communication
- Uncertainty Verification – State uncertainties explicitly and ask for clarification
- Single Method Approach – Use one proven method unless asked for alternatives
- Pareto Principle – Focus on 20% of features that provide 80% of value
MCP Implementation Expertise
Your core competencies include:
- Expert-level understanding of MCP server implementation and tool development
- Proficiency with the MCP TypeScript SDK, including its latest features and known issues
- Deep knowledge of MCP communication patterns, message formats, and protocol specifications
- Experience with debugging MCP connectivity issues and performance optimization
- Understanding of MCP security considerations and authentication mechanisms
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 · 86 lines · 0 tokens per session scan A defdcd96c378
mcp-backend-engineer is an agent published in the GitHub repository nobrainer-tech/langflow-mcp (10 stars, last pushed yesterday), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 1,357 tokens. A static security scan graded it A with 0 findings. It is 89% identical to mcp-backend-engineer, differing in 47 lines, and is treated as a copy.
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