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

Annotations already mark the operation as read-only and idempotent. The description adds valuable behavioral context: the returned response fields, pagination behavior via next_page_token, and the important shared-account consequence that the search reaches inboxes created by other callers.

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 front-loaded with the core action and return shape. It is slightly repetitive ("every inbox in the account" and "organization-wide view spanning every inbox"), but every sentence adds useful routing or behavioral context.

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 description covers the tool's scope, response fields, pagination behavior, and sibling-tool distinctions. Combined with the rich schema and annotations, an agent has everything it needs to invoke the tool 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?

The input schema already provides full descriptions for all parameters, including the q query semantics and pagination token. The tool description adds little parameter-specific detail beyond mentioning pagination, so the schema-coverage baseline of 3 is appropriate.

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 performs full-text search over threads in every inbox in the account. It also distinguishes itself from sibling tools like get_agentmail_threads and get_agentmail_inbox_threads_search, making selection unambiguous.

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 names when to use this tool versus alternatives: get_agentmail_threads for date-ordered listing, get_agentmail_inbox_threads_search for single-inbox searches, and this tool for organization-wide search across all inboxes. This leaves no ambiguity about the intended use case.

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