Download Media Attachment to Local Disk

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

Annotations already expose mutability (readOnlyHint=false), idempotency, and non-destructive behavior. The description adds the operational constraint that the destination path must be within configured MCP allowed roots, which is useful beyond the 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?

Three short sentences, front-loaded with the core purpose, followed by the key constraint and the alternative tool. No filler or repetition.

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 download operation, the description explains what it does, the key path constraint, and the metadata alternative; an output schema exists, so return-value details are not necessary. Minor ambiguity about the default destination when file_path is omitted prevents a 5.

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 baseline is 3. The description adds the 'destination path' framing, but it largely restates file_path's root constraint and does not clarify the file_path schema phrase about 'upload or send' or the behavior when file_path is omitted.

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 first sentence names a specific operation ('Download an attachment or media file'), the resource (message attachment), and the destination (local filesystem). It clearly distinguishes itself from siblings like get_media_info (metadata only) and send_file (upload).

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 gives clear context: use it to physically fetch media, and use get_media_info when only metadata is needed. It lacks an explicit exclusion for send_file or a fuller when-not-to-use statement, but the main alternative is named.

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