school_mail_download_attachment

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

Annotations declare readOnlyHint=false but destructiveHint=false and idempotentHint=false, leaving the nature of the write ambiguous. The description resolves this by clarifying that it writes a local file while leaving mailbox content unchanged, which is valuable disambiguation beyond the annotations. It does not cover overwrite behavior or permissions.

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 compact sentences with the action and destination front-loaded, followed by the part_index source and the mailbox-unchanged caveat. No filler, though it could be marginally tighter.

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?

An output schema exists, so the returned path need not be explained in prose. Combined with annotations covering the safety profile and the description covering the write scope and part_index origin, the definition is nearly complete; only the target directory rules and overwrite semantics are absent.

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 0% across 4 parameters, so the description must compensate. It meaningfully explains the non-obvious part_index (sourced from the mail's attachment list), but uid, uid_validity, and mailbox remain undocumented; uid_validity in particular is an IMAP-specific value an agent may not infer.

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 and resource: save the specified mail attachment to the project's local private directory and return the path. This is clearly distinct from the read/search/list siblings, though it does not explicitly name them. The scope of the operation (local save, not mailbox change) 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 a workflow prerequisite by stating that part_index comes from the attachment list obtained when reading the mail, which is useful context. However, there is no explicit when-to-use vs alternatives guidance or statement of when this tool should not be chosen over school_mail_read.

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