gmail_messages_get

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

Annotations already declare readOnlyHint, idempotentHint and openWorldHint, so the safety profile is fully covered by structured fields. The description adds no behavioral context at all beyond the annotations — no return shape, no notes on large/raw payloads, no scope restrictions (e.g., full/raw being unavailable under gmail.metadata).

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?

A single short sentence with the action front-loaded and no filler. Slightly awkward phrasing ('by the id messages_list returns') but nothing wasted.

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 single-item read tool, the combination of rich schema documentation and accurate annotations covers most of what an agent needs. The description is adequate but adds little; with no output schema, some hint about the returned representation would have helped, though the format parameter documents this in the schema.

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 100%, so all four parameters (id, format, userId, metadataHeaders) are already fully explained by the schema, including format enum behavior and Gmail's defaults. The description adds only the provenance of the id, which the schema also states, so baseline 3 applies.

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 (Read) and resource (one message), and the singular scope clearly separates it from the sibling gmail_messages_list. It stops short of an explicit contrast statement, but an agent can still tell the two apart.

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 tells the agent where to get the id ('messages_list returns'), which is implied usage guidance for a prerequisite step. It says nothing about when to prefer this over siblings like gmail_threads_get or how to handle missing/deleted ids.

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