search_messages

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

The description explicitly says 'Read-only', consistent with annotations. It details query behavior (free-text search, KQL), folder types, date range formats, and max messages. No contradictions with annotations; adds significant behavioral context.

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 well-structured docstring with a clear one-line purpose followed by a bulleted parameter list. Every sentence provides value; no redundancy. It is appropriately concise for the complexity.

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 no output schema, the description could mention return fields (e.g., message metadata). It explains inputs thoroughly but omits output structure. Still, it covers core functionality well for most use cases.

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?

With 0% schema description coverage, the description fully explains each parameter: query (KQL search), folder (well-known or custom), top (1-100), since (ISO 8601 or relative). This adds essential meaning beyond the schema's default values.

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 starts with 'Search or list mail messages. Read-only.' which clearly states the action (search/list) and resource (mail messages). It distinguishes itself from siblings like get_message (single message) and list_inbox_rules (rules management).

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 explains that an empty query lists messages, provides example KQL syntax, and mentions folder restrictions. It implicitly tells when to use this tool vs siblings (e.g., not for a specific message). The 'Read-only' note clarifies it's safe.

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