fetch_email_attachment

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It effectively describes the operation (download), prerequisites (requires IDs from fetch_email_content), and return format (including contentBase64 encoding). It does not mention potential errors, rate limits, or authentication needs, but covers core behavior adequately for a read operation.

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 front-loaded with the core purpose in the first sentence, followed by prerequisites and return details. Every sentence adds essential information without redundancy, making it efficient and well-structured for an AI agent.

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?

Given the tool's moderate complexity (download operation with 3 parameters), no annotations, and no output schema, the description does a good job covering purpose, prerequisites, and return format. However, it lacks details on error handling or edge cases (e.g., invalid IDs, large files), which would enhance completeness for a tool without structured output documentation.

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 already documents all parameters (id, attachment_id, mailbox). The description adds minimal value beyond the schema by mentioning that attachment_id is 'obtained from fetch_email_content', but does not provide additional syntax, format, or usage details for parameters. This meets the baseline for high schema coverage.

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 specific action ('Download a specific attachment from an email'), identifies the resource ('attachment'), and distinguishes it from sibling tools like fetch_email_content (which provides attachment IDs) and list_emails_* tools (which list emails rather than download attachments). The verb 'download' is precise and 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 explicitly states when to use this tool ('Requires the email id and the attachment id (obtained from fetch_email_content)'), providing clear prerequisites. However, it does not specify when NOT to use it or mention alternatives (e.g., if there are other ways to get attachments), which prevents a perfect score.

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