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

Description discloses key behaviors beyond annotations: it waits up to 240 seconds, processes only the current post's first MP4, and returns job_id plus next query action if incomplete. This adds meaningful context that annotations alone do not provide, without contradicting them.

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 dense sentence that front-loads the core purpose and then adds critical constraints and fallback behavior. There is no filler or repetition of schema details.

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 only one parameter, a full schema, output schema availability, and annotations, the description covers the essential operation, the time limit, the video-selection rule, and the asynchronous fallback. Nothing material is missing for an agent to invoke this tool correctly.

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%, so the baseline is 3. The main tool description does not add further parameter-level semantics beyond what the schema already explains about post_url; it correctly does not need to compensate.

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?

Description clearly states the action (submit speech-to-text task), the resource (X/Twitter video post URL), and the precise scope (only the first available MP4 in the current post). It is distinguishable from the sibling x_submit_video_speech_text_by_post_id because the tool is explicitly URL-based.

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 parameter schema specifies '仅在没有 post_id 时' (only when there is no post_id), which gives a clear condition for choosing this URL-based tool over the post_id variant. However, it does not explicitly name sibling tools or provide a fuller when-not-to-use statement, so it falls just short of fully explicit alternative routing.

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