mcp-builder
Pass
Audited by Gen Agent Trust Hub on Sep 18, 2026
Risk Level: SAFECOMMAND_EXECUTIONEXTERNAL_DOWNLOADSINDIRECT_PROMPT_INJECTION
Full Analysis
- [COMMAND_EXECUTION]: The evaluation harness and connection library support launching local processes as MCP servers.
- Evidence in
scripts/evaluation.pyandscripts/connections.py: Thestdiotransport mode uses themcpSDK to execute commands (e.g.,python server.py) provided by the user via command-line arguments to facilitate local testing and development. - [EXTERNAL_DOWNLOADS]: The skill documentation directs the agent to retrieve the latest protocol specifications and SDK documentation from official sources.
- Evidence in
SKILL.md: Instructs the agent to useWebFetchto load documentation fromhttps://modelcontextprotocol.ioand raw README files from themodelcontextprotocolorganization on GitHub. These sources are established for the protocol and are used exclusively for retrieving informational markdown files. - [INDIRECT_PROMPT_INJECTION]: The skill provides an evaluation script that processes external data files, which creates a surface for indirect prompt injection during testing.
- Ingestion points:
scripts/evaluation.pyparses XML files (e.g.,scripts/example_evaluation.xml) containing test questions that are passed directly into the LLM's prompt. - Boundary markers: The system prompt in
scripts/evaluation.pydefines specific output tags (<summary>,<feedback>,<response>) to structure the model's output and mitigate instruction leakage, though the input questions are not encapsulated in unique delimiters. - Capability inventory: The agent being evaluated has access to the tools exposed by the MCP server being tested via the
connection.call_toolmethod. - Sanitization: The questions extracted from the XML are not sanitized or escaped before interpolation into the prompt, as the script is intended for use with developer-controlled test suites.
Audit Metadata