gmail_messages_attachments_get

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

Annotations already declare readOnly/idempotent/openWorld, so safety is covered. The description adds real behavioral value beyond them: text attachments return as text and binary ones are 'reported, not decoded', which sets return expectations for a tool with no output schema.

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?

Two tight sentences with zero filler; the core action and the id provenance are front-loaded, and the return-format caveat follows.

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 read-only tool with no output schema, the description covers the important unknown (how content is returned). What 'reported, not decoded' actually looks like for a binary attachment remains slightly ambiguous.

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%, so both required params and userId are documented in the schema; baseline is 3. The description clarifies where the attachmentId originates, but adds no format or constraint detail beyond 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?

Specific verb+resource ('Read one attachment') and it explicitly names the sibling tools (messages_get, threads_get) that produce the attachmentId, so the agent can place it precisely among the gmail_* family.

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?

States the context of use by tying the call to the id returned by messages_get/threads_get, which is the key prerequisite. It does not, however, state any exclusion or alternative for fetching attachment content another way.

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