Search a Gmail account

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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the agent knows it is safe. The description adds valuable context: default returns headers/snippets, include_body controls full text, and a security warning that message content is untrusted. This goes beyond annotations and covers the key behavioral aspect of the returned data.

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 sentences, each earning its place: purpose with example, default return behavior, and a security caution. Information is front-loaded and no words are wasted. The structure is clean and immediately actionable.

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 lacking an output schema, the description explains what is returned (headers, snippets, optional full body) and warns about untrusted content. It also clarifies the account parameter source. For an agent, this is sufficient to invoke the tool and interpret results 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 75%, so the description is not required to fully compensate, but it adds meaning: it explains include_body's purpose (read full text) and gives a query syntax example that clarifies the query parameter. max_results lacks a schema description and is not addressed in the description, which is a minor gap, but the overall added value is solid.

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 uses a specific verb ('Search') with a clear resource ('one account') and scope via Gmail query syntax. It distinguishes itself from sibling read tools like gmail_read_message and gmail_read_thread by focusing on search across the account. The example query reinforces purpose.

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 clearly indicates use for searching an account with Gmail query syntax and provides a concrete example. It references the account parameter from gmail_list_accounts, implying a prerequisite. It does not explicitly state when not to use it or name alternatives, so it falls short of a 5.

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