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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds minimal extra behavioral context beyond scope ('user's library'), but does not disclose pagination, ordering, or default workspace behavior beyond what schema already provides.

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 a single sentence that directly states the tool's purpose without redundancy or filler. It is front-loaded and every word contributes meaning.

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 filtered-list tool, the description is sufficient when combined with complete schema documentation, strong annotations, and an output schema. There are no complex behaviors or hidden side effects to explain.

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 each parameter documented (limit, offset, assetType, workspaceId). The description adds no new parameter nuance beyond mentioning media types, which duplicates the assetType enum. Baseline 3 is appropriate because the schema carries the semantic load.

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 ('List') and resource ('media files in user's library'), and clarifies scope with media types ('videos, audio, images'). This clearly distinguishes it from siblings like media_assets_get (singular asset retrieval) and media_folders_list (folders).

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 implicitly establishes usage context: use this tool to list media assets in the user's library. It doesn't explicitly name alternatives or exclusions, but the purpose is clear enough and no conflicting sibling offers the same list functionality with these filters.

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