search_messages

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

Declares 'Read-only with no side effects', which covers safety. No annotations exist, so description carries full burden. Could mention search scope (message bodies only) but is adequate.

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?

Two sentences only, no wasted words. Front-loaded with purpose and scope.

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 output schema exists, description is comprehensive: covers usage scope, safety, sorting, and links to alternative. Only minor omission is pagination details, but acceptable.

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. Description adds value by explaining scope ('within one chat or across all chats') and sort order ('newest-first'), enhancing what schema provides.

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?

Clearly states the tool searches message bodies by keyword, within one chat or all, and returns newest-first. Distinguishes from sibling read_messages by specifying its use for content search versus chronological browsing.

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 tells when to use ('to find messages by content') and when not to ('use read_messages instead to browse a specific chat chronologically'), with a direct sibling alternative.

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