retrieve_tools

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

While annotations provide readOnlyHint=true (read-only) and destructiveHint=true (contradictory internally), the description explains the tool's behavior well: it performs BM25 search, excludes quarantined servers, and returns results with annotations and call_with recommendations. It does not contradict annotations but adds context beyond them. The internal annotation contradiction is not reflected in the description.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is relatively long but well-structured and front-loaded with the most critical instruction. Each sentence provides useful information (usage guidance, search algorithm, result contents, exclusions, server addition). While it could be slightly more concise, the structured information justifies the length for an important tool discovery mechanism.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given the tool's complexity (5 parameters, no output schema, annotations present), the description covers purpose, usage guidelines, behavioral details, parameter usage, and related tools. It partially covers output by mentioning 'annotations' and 'call_with' recommendations. It could mention pagination or error handling, but the existing information is largely sufficient for an agent to invoke this tool correctly.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100%, so baseline is 3. The description adds meaningful context for parameters: it explains that 'query' should be a natural language description with examples, that 'debug' enables ranking explanations, and how 'explain_tool' works in debug mode. This adds value beyond what the schema provides, justifying a 4.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the tool's purpose: 'CALL THIS FIRST to discover relevant tools!' It specifically identifies the action (retrieve tools), the resource (tools across all MCP servers), and the method (BM25 full-text search). It distinguishes itself from sibling tools by being the primary discovery mechanism and explicitly advises using it before calling any specific tools. The verb 'retrieve' combined with the explanatory text provides excellent clarity.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description provides explicit guidance: 'Always use this before attempting to call any specific tools' and 'Use natural language to describe what you want to accomplish.' It also tells when not to use this tool (quarantined servers) and directs to alternatives: 'Use 'quarantine_security' tool to examine and manage quarantined servers' and 'Use 'list_registries' then 'search_servers' to find and add new MCP servers.' This clearly differentiates when to use this tool versus siblings.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.