Search messages

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It only states the basic search operation and does not reveal how filters combine, what the return format is, whether it returns full messages or metadata, or any other runtime behaviors. This is a significant gap for a search tool.

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 consists of a single, tight sentence that is front-loaded with the action and resource. It is concise and free of unnecessary words, making it easy for an agent to quickly grasp the tool's core purpose.

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 5 parameters, no required fields, no output schema, and only 60% schema description coverage, the description is insufficient. It does not explain the meaning of all parameters, the behavior of filters in combination, or what a successful search returns. This leaves the agent with many unknowns.

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 description lists three filter criteria (sender, subject, body text) that map to the from, subject, and text parameters. However, the schema already provides descriptions for these fields, so the description adds no new meaning. It omits the limit and mailbox parameters entirely, leaving those without any description to compensate for schema gaps.

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 function: searching a mailbox by sender, subject, or body text. It uses a specific verb and resource, and the criteria distinguish it from list_messages (which lists without search) and get_message (which retrieves a single 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 tool is for searching messages with specific filters, but it does not explicitly state when to use this tool over list_messages or get_message, nor does it mention any exclusions or alternative tools. The context is implied by the search criteria but not elaborated.

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