search_tools

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

Annotations include readOnlyHint and openWorldHint, so the description doesn't need to restate safety. It adds behavioral context by explaining it returns 'matching tool names + descriptions ranked by relevance' and operates 'without loading every definition', which is useful and not redundant with annotations.

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?

Three sentences: the first states the main function, the second gives return details, and the third provides use-case context. No fluff, every sentence adds value, and the key information is front-loaded.

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 simplicity, the description fully covers purpose, usage, return contents, and context. The absence of an output schema is compensated by the explicit description of what is returned. Even with a large sibling list, this tool's role is clear and self-contained.

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 description coverage is 100%, and the schema already provides clear descriptions for 'query' and 'limit'. The description reinforces the keyword search nature but doesn't add significantly beyond the schema, so the baseline of 3 is appropriate.

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 with a specific verb ('Search'), resource ('full NowAIKit tool catalog'), and outcome ('discover the right tool'). It distinguishes itself from sibling tools by being a meta-search tool rather than a domain-specific operation.

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?

Explicitly instructs to 'Use this FIRST when you are unsure which tool to call' and mentions the specific benefit with MCP_TOOL_DISCOVERY=lean. This provides clear when-to-use guidance and differentiates it from direct task tools.

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