search_messages

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

With no annotations provided, the description must carry the full burden of behavioral disclosure. It usefully discloses that only up to 500 recent messages are scanned, which is a key limitation. However, it does not explicitly state that the operation is read-only, nor does it mention any authentication requirements or side effects.

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, front-loaded sentence that immediately communicates the core purpose and key constraint. Every word earns its place, with no filler or repetition of schema 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?

The tool is simple with three fully documented parameters, but there is no output schema and the description does not explain the return format or behavior for empty results. While the phrase 'Search for messages' implies a return of matching messages, the lack of explicit return-value details leaves some ambiguity, especially given the 500-message scan limit.

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%, so the parameters are fully documented in the schema itself. The description does not add additional meaning beyond what the schema provides, such as how limit interacts with the 500-message scan scope. This aligns with the baseline of 3 for full schema coverage.

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 action (search), the target resource (messages), and the specific scope (containing a keyword in a channel). This distinguishes it from sibling tools like get_messages, which likely retrieves messages without keyword filtering, and 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 implies the use case (keyword search within a channel) but provides no explicit guidance on when to choose this over get_messages or other sibling tools. It does mention the 500-message scanning limit, which helps set expectations, but lacks explicit exclusions or alternatives.

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