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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint, and the description's 'Read-only' is redundant with those. However, it adds useful behavioral context beyond the schema by specifying exactly what the search returns: matching message summaries and extracted_text, which is valuable since no output schema exists.

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?

Three short, purposeful sentences: action/scoping, safety trait, and return value. No filler or redundant elaboration. The most important information is front-loaded.

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 simple two-parameter search tool with safety carried by annotations, the description gives enough return-shape information ('message summaries and extracted_text') to inform usage. It doesn't mention pagination, defaults, or query syntax beyond the schema, but those are minor given the tool's low complexity.

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 schema already describes 'q' as an AND-across-tokens search query, but 'limit' has no schema description. The tool description adds no additional parameter meaning, so the 50% schema coverage gap for 'limit' is not compensated. The meaning of 'limit' is fairly self-evident, keeping this at a mid-level score.

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 a specific action ('Search stored Cooper mail for this account') and the result format ('message summaries and extracted_text'). It does not explicitly differentiate from similar sibling tools like cooper_list_messages or cooper_get_message, but 'search' plus 'matching' makes the resource and operation clear.

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 siblings such as cooper_list_messages or cooper_get_message. The phrase 'for this account' provides some scope, but there are no exclusions, alternatives, or use-case conditions to help the agent choose correctly.

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