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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is covered. The description adds useful scope information ('your uploaded media files') and return content details, but it doesn't disclose behaviors like pagination defaults or ordering. With strong annotation coverage, this is adequate but not exceptional.

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 each earn their place: the first states the action, the second lists what is returned, and the third explains a practical downstream use. There is no redundancy or filler.

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 simple, read-only list tool, the description is complete: it states scope, return fields, and a relevant use case. The schema covers parameters, annotations cover safety, and the description covers what the agent will receive. No essential information is missing.

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%, with both limit and offset already described as 'Number of media items to return' and 'Offset for pagination'. The description adds no parameter-specific detail beyond this, so the schema carries the burden and the baseline of 3 is appropriate.

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 verb ('List') and resource ('your uploaded media files'), and the mention of returned media IDs, URLs, and types distinguishes it from sibling tools like upload_media or delete_media. An agent can immediately identify what action this tool performs.

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 provides clear context: it lists uploaded media and notes that media IDs are useful when creating posts with previously uploaded content. However, it doesn't explicitly state when not to use it or name alternative tools, though the usage context is sufficient for most cases.

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