Download an attachment

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

Annotations already indicate this is a write operation (readOnlyHint=false) and not destructive (destructiveHint=false). The description adds materially useful context: writes are confined to EMAIL_ATTACHMENT_DIR and filenames are sanitised, which clarifies side-effect scope and security behavior. This goes beyond the annotations without contradicting them.

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?

Three short sentences deliver the action, result, and key behavioral constraints with no redundancy. The most important information is front-loaded, and every sentence 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?

For a tool with full schema coverage, an output schema, and annotations covering read/write/destructive hints, the description is sufficiently complete. It adds security and scope constraints that matter for safe invocation. Minor omissions like overwrite behavior or error handling are not critical given the available structured metadata.

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 parameters are fully documented in the schema. The description does not add parameter-level meaning, but it also does not need to because the schema already explains uid, folder, and filename. The baseline of 3 applies because the description offers no supplementary parameter insight.

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 specific action ('Save an attachment'), the destination ('server's attachment directory'), and the result ('return its path'). It clearly distinguishes itself from the sibling tools, none of which handle attachment downloading.

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 purpose implicitly defines when to use this tool: when a downloaded attachment is needed. However, there is no explicit guidance about when not to use it or which alternatives to prefer. The description does not mention exclusions or conditions beyond the simple action, so guidance is implied rather than stated.

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