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 rules/fortunto2/prefect-mcp-server/build_mcp_pythongit clone --depth 1 https://github.com/fortunto2/prefect-mcp-serverWhat 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 | $0.04345 | $0.04345 |
| Opus 5 | $0.02173 | $0.02173 |
| Sonnet 5 | $0.00869 | $0.00869 |
| Haiku 4.5 | $0.00434 | $0.00434 |
Grade A, and why
build_mcp_python scanned grade A with 1 finding 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 yesterday.
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.
Asks the agent to reveal its instructionslowSystem prompt leakage
Directions to print, repeat or translate the system prompt extract configuration the operator did not intend to expose.
"""Create an echo prompt""" Downgraded: this mod is about security review, or the phrase is quoted, so it is likely naming the pattern rather than instructing it.
How it starts
The opening of the file, as written. The whole thing — 654 lines — stays where its author put it; the contents beside it link to each section on GitHub.
MCP Python SDK
Python implementation of the Model Context Protocol (MCP)
Table of Contents
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.
- yesterday First seen · 654 lines · 4,345 tokens per session scan A 873bd208370f
build_mcp_python is a cursor rule published in the GitHub repository fortunto2/prefect-mcp-server (7 stars, last pushed 10mo ago), licensed MIT. It adds 4,345 tokens to every session, about $0.0217 per session on Opus 5. A static security scan graded it A with 1 finding (asks the agent to reveal its instructions). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.
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