gmail_search_messages

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

Annotations already declare readOnlyHint=true, destructiveHint=false, idempotentHint=true, and openWorldHint=true, so 'Read-only' in the description is redundant. The one piece of added context is the return shape ('message IDs with snippet and labels'), which is useful but thin, and nothing is said about pagination behavior despite a page_token parameter.

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 sentences with zero filler, and the level distinction is front-loaded before the return-shape detail. Nothing needs trimming.

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 search tool with no output schema, the brief return description helps, but two of three parameters are undocumented and pagination via page_token is never explained. An agent could call it on the required query alone, but would not know how to page or cap 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 description coverage is only 33%, so the description carries most of the burden, yet it explains no parameters at all. The query syntax is conveyed only by the schema's inline example, and page_token and max_results (with its 1-50 cap and default 10) are undocumented in both the description and the schema.

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?

States a specific verb and resource ('Searches Gmail at message level') and immediately contrasts it with the sibling that operates at thread level, gmail_list_threads. An agent can distinguish this from gmail_list_threads without opening either schema.

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?

Names the alternative gmail_list_threads explicitly and gives the condition that selects this tool ('message level vs thread level'). However, it does not address other plausible alternatives in the sibling set such as gmail_semantic_search or gmail_get_message_details, leaving the boundary partially inferred.

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