Save an attachment for reading

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

Annotations already declare readOnlyHint=true, destructiveHint=false, and idempotentHint=true. The description adds the specific behavior of saving to a configured temporary directory, which is beyond annotations and informs the agent of a side effect (writing a local file) that is still non-destructive. No contradiction with annotations.

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 sentence that is front-loaded with the core action ('Save one attachment') and provides a concise purpose. No wasted words; every word earns its place.

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?

The tool is simple, has an output schema, and annotations cover safety. The description adds the essential behavior of saving to a temp directory. It lacks an explicit hint about needing to call get_email first, but that is inferable from the schema and sibling names. Overall, sufficient for a low-complexity 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 description coverage is 100%, so the schema fully documents id and attachment_id. The description does not add extra parameter-level meaning beyond noting 'one attachment' and the temp directory. Baseline 3 is appropriate when schema carries the parameter semantics.

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 states a clear verb ('Save') and resource ('one attachment') with a purpose ('for reading'). It is distinct from siblings like get_email (which retrieves content) and get_thread (which retrieves threads), so the purpose is unambiguous.

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 when needing to read an attachment, but it does not explicitly state when not to use it or mention alternatives. There is no guidance on the prerequisite of calling get_email to obtain an attachment_id, though the schema description covers that. Thus, usage context is clear but exclusions/alternatives are absent.

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