search_messages

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

Annotations already mark readOnlyHint=true and destructiveHint=false, covering safety. The description adds that it is a 'Full-text search' (searching entire message content) and mentions 'Graph $search', which signals specific API behavior. However, it does not disclose pagination behavior, query syntax, or result ordering, so transparency is limited but present.

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?

A single sentence conveys the core purpose without unnecessary words. It is concise and front-loaded, though it lacks structure like usage examples. It is appropriately sized for a simple search tool.

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?

Despite having an output schema and simple parameters, the description omits essential context for effective use: no query syntax guidance, no note on result limits, and no relation to sibling tools. The tool is part of a rich email/calendar set, and this description leaves an agent with too little to select and invoke it correctly.

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 0%, so the description must compensate for undocumented parameters. It does not explain what 'query' should contain (e.g., KQL syntax) or what 'top' limits (e.g., number of results). The phrase 'Full-text search' implies query is the search string, but no syntax or defaults are clarified.

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 verb ('search') and the resource ('the mailbox'), specifying 'Full-text search' to indicate scope. It distinguishes from siblings like 'search_events' (which searches calendar events) and 'list_messages' (which lists without full-text search).

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?

No guidance is given on when to use this tool versus alternatives. The description does not mention exclusions or reference sibling tools, so an agent cannot tell from the description alone whether to use search_messages or list_messages / search_events for a given task.

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