search_messages

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

There are no annotations to disclose read-only or destructive behavior. The description only mentions 'search', suggesting a read operation, but does not explicitly state that it does not modify data, nor does it mention authentication or rate limits. It does not contradict any annotations (none provided), but it fails to carry the burden of behavioral disclosure without them.

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 a single, well-formed sentence that directly states the tool's purpose without any filler. It is front-loaded and concise, ideal for an agent to quickly understand the tool's function.

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?

For a tool with only 2 parameters and no output schema, the description is adequate but minimal. It does not describe the return format (e.g., message objects, IDs, or metadata), nor does it mention pagination or result sorting. While the simplicity of the tool lowers the bar, the description omits details that would help an agent anticipate the response shape, making it incomplete.

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?

The schema already provides 100% coverage, documenting both parameters. The description's phrase 'by contact name, phone number, or message content' mirrors the schema's description of query, adding no new meaning. The limit parameter is not mentioned, but its schema description is sufficient. Since the schema does the heavy lifting, the description adds minimal value beyond it.

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 for messages using specific criteria (contact name, phone number, or content). It distinguishes from siblings like read_recent_messages (retrieves recent messages) and get_conversation (fetches a full conversation). The verb 'search' plus the resource 'messages' and the scope of search fields make the purpose unambiguous.

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 implies when to use the tool: when you need to find messages by contact details or content. However, it does not explicitly contrast with alternatives like read_recent_messages or list_chats_structured, nor does it state when not to use it. The guidance is clear but not exhaustive.

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