mcp-builder
Warn
Audited by Gen Agent Trust Hub on Mar 4, 2026
Risk Level: MEDIUMCOMMAND_EXECUTIONEXTERNAL_DOWNLOADSPROMPT_INJECTION
Full Analysis
- [COMMAND_EXECUTION]: The
scripts/connections.pyandscripts/evaluation.pyfiles implement functionality to spawn subprocesses on the local system. Specifically, theMCPConnectionStdioclass uses thestdio_clientto execute commands provided via CLI arguments. While intended for testing local MCP servers, this provides a direct path for arbitrary command execution on the host. - [EXTERNAL_DOWNLOADS]: The
SKILL.mdfile directs the agent to fetch documentation and SDK information from the officialmodelcontextprotocolorganization on GitHub. These references are used to provide the agent with the necessary context for server implementation and are documented as trusted sources. - [PROMPT_INJECTION]: The
scripts/evaluation.pyscript ingests data from external XML files (qa_pairelements) and tool responses, which are then fed directly into the LLM context. This creates an indirect prompt injection vulnerability where malicious data from a tested API or a crafted evaluation file could influence the agent's behavior during the evaluation loop. - Ingestion points:
scripts/evaluation.pyreads from XML files viaparse_evaluation_fileand tool outputs viaconnection.call_tool. - Boundary markers: The script uses XML tags like
<summary>,<feedback>, and<response>to structure the agent's output, but it does not apply strict delimiters or 'ignore instructions' guards to the untrusted tool data being read. - Capability inventory: The skill can execute local commands via
stdiotransport and make network requests via SSE/HTTP transports and the Anthropic API. - Sanitization: The script performs JSON encoding for structured tool results but does not sanitize or filter the content of strings returned by tools before inclusion in the prompt.
Audit Metadata