search_messages

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

Since no annotations are provided, the description fully explains behavior: hybrid ranking, mode field reporting, auto-collection, local search, and honest notice on empty index with no session. No contradictions or omissions.

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 concise (3-4 sentences) with front-loaded purpose. Every sentence provides essential information about ranking, auto-collection, and error handling. No redundancy or unnecessary details.

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 absence of output schema and the complexity of hybrid search and auto-collection, the description covers all critical aspects: ranking details, mode field, behavior under different index states, and honesty about empty results. It is complete for an AI agent to understand.

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?

Although input schema coverage is 100% with descriptions for both parameters, the tool description adds significant value beyond the schema: it explains that query accepts plain keywords and natural-language descriptions, and that limit controls maximum results. This enriches the semantic understanding.

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 searches across LINE messages, distinguishing it from other tools. It specifies hybrid ranking (FTS5 + semantic) and the mode field, which gives a precise purpose and differentiates it from siblings like collect_messages or send_message.

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 guidance on when to use: auto-collects if index empty and session live, searches locally if populated, returns honest notice if empty and no session. It implicitly tells agents not to use it for sending or manipulating messages, but lacks explicit 'when not to use' or mention of alternatives.

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