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

The description is rich in behavioral detail (server downloads, immediate return, asset lifecycle, quota, idempotent re-submission), but it contradicts the idempotentHint annotation. The annotation says idempotentHint: false, yet the description states 'Re-submitting the same URL to the same channel returns the original asset instead of importing twice,' which is idempotent behavior. This direct contradiction triggers a score of 1 per the rules.

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 dense but every sentence provides necessary constraints or behavioral context. It is front-loaded with purpose, then details usage limits, process, quota, and idempotency. No wasted words; structure is logical and appropriately sized for the tool's complexity.

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?

Given the tool's complexity and lack of output schema, the description covers return behavior ('Returns immediately; asset then goes downloading -> pending -> transcoding -> ready'), quota impact, and edge cases like re-submission. It also references set_asset_weight for weight adjustments, providing a complete picture for effective use.

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 description adds significant meaning for the url parameter by detailing acceptable formats and exclusions, far beyond the schema's 'Direct, public media URL.' It also clarifies the weight parameter's purpose and timing ('Set it here rather than after'). However, channel_id, tags, and title remain undocumented beyond their schema entries, and schema coverage is only 40%, so the description does not fully compensate for all parameters.

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's function: 'Add a video to a channel from a direct media URL.' It also specifies this is the main way to add content over MCP, distinguishing it from local file uploads and other tools. The verb and resource are specific, and the mention of 'not a YouTube/Vimeo watch page' helps differentiate from import_youtube_video.

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 explicit when-to-use and when-not-to-use guidance. It states the URL must be a direct, public, unauthenticated link to specific formats, not a web page, not behind a login, and not a YouTube/Vimeo watch page. It also advises on handling local files and mentions the quota. This clearly defines the tool's intended use versus alternatives.

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