download_post_attachment

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

No annotations are provided, so the description carries full burden. It clearly covers different behaviors (save to disk, return ImageContent for supported types, error for unsupported) and lists supported file types, but does not mention file overwrite policies 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?

The description is well-structured with sections, bullet points for file types, and clear arg descriptions. It front-loads the core action, though could be slightly more concise.

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?

No output schema exists, but the description covers all return types (ImageContent, DownloadAttachmentResponse, DownloadAttachmentErrorResponse, error string). All parameters are explained, and supported file types are listed, making the tool self-contained.

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?

The input schema has no parameter descriptions (0% coverage), but the description's Args section fully explains all 4 parameters, including the purpose of output_path and that file_guid comes from get_post_attachments.

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 tool downloads a specific attachment from a post, with a specific verb and resource. It differentiates from siblings by explicitly covering file download behavior.

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 explains usage conditions based on output_path and file type, but does not explicitly state when not to use this tool or compare to sibling tools like get_post_attachments or upload_file_to_chat.

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