Download media from a message

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

The description adds behavioral details beyond annotations: the download destination directory, an environment variable override, and the return of the absolute path. This is consistent with readOnlyHint (no remote state mutation) and provides practical context.

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 concise sentences, front-loaded with the core purpose, and every word adds value. No redundant or extraneous information.

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 straightforward download tool, the description covers the key operational aspects: where files are stored, how to override the path, and what is returned. It lacks edge cases (e.g., no media attached) but is adequate given the simple nature and the absence of an output schema.

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%, and the description does not explain the meaning or purpose of peer, messageId, or accountId. The parameter names are somewhat self-explanatory, but the description fails to add any clarifying value, leaving a significant gap.

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 uses a specific verb 'download' and resource 'media attached to a message', clearly distinguishing it from siblings like download_profile_photo. It also specifies where files land, reinforcing the purpose.

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 intended use is clear: download media from a message. It does not explicitly state when to avoid using it or compare to alternatives, but the context is sufficiently clear without being misleading.

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