gmail_search_messages

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

With no annotations, the description bears the full burden of disclosing behavior. It does not state whether the tool is read-only, what the response contains (list of message IDs vs. full messages), whether authentication is required, or any pagination/rate-limit behavior. The examples of Gmail syntax provide some operational context, but significant behavioral traits remain undisclosed.

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 a single, front-loaded sentence that immediately states the action and resource. It uses parentheses for examples, keeping the main clause clean. Every word earns its place, and there is no redundancy or filler.

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?

There is no output schema, so the description should clarify what the tool returns. It does not mention whether results are full message objects, summaries, or just IDs. It also omits any prerequisites (e.g., account must be authenticated) and does not reference pagination behavior despite the pageToken parameter. This leaves the agent under-informed for a search tool.

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 100%: all four parameters (query, accountId, pageToken, maxResults) have descriptions. The description adds value by giving example query values, which helps understand the 'query' parameter. However, it does not elaborate on other parameters beyond what the schema already states, so the 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's function: 'Search for messages in Gmail using Gmail search syntax'. It provides concrete examples ('from:user@example.com', 'subject:hello', 'is:unread') that illustrate the query format. This differentiates it from sibling tools like gmail_get_message (fetch a specific message) and gmail_list_labels (list labels).

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 implies usage by giving search syntax examples but does not explicitly state when to choose this tool over alternatives like gmail_get_message or gmail_get_messages_batch. It lacks exclusions or explicit situational guidance, so it falls into the 'implied usage' category rather than clear context with alternatives.

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