search_messages

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

The description discloses sorting order, output format (#N), and parameter behaviors such as limit's upper bound and include_preview's effect on response length. Even with readOnlyHint true, it adds useful context beyond the annotation.

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 begins with a one-line purpose, then formatted Args with concise bullet-like explanations. Every parameter earns its place, and the structure makes it easy to scan. No unnecessary words.

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 output schema exists, so return values need no explanation. The description covers the search orientation, sorting, ID format, and all parameter constraints, making it sufficiently complete for correct invocation.

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?

All 8 parameters are described with richer semantics than the schema provides: query covers subject/body, from_address is partial match, since/until specify date format, and limit has explicit defaults and max. This fully compensates for the 0% schema description 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 tool searches emails in descending order and that the leading #N is a short ID for organizing tools. This distinguishes it from sibling tools like get_message (single message) and move_by_search (search-and-move).

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 positions this as the search entry point that provides short IDs for other organizing tools, making its use case clear. It doesn't explicitly list alternatives or exclude other tools, but the context is unambiguous enough for an agent to select it when searching is required.

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