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

Annotations only declare write/destructive/idempotent-false; the description goes well beyond them by disclosing the credit cost source (the price get_video lists in after_steps), the refund-on-failure behavior, the content validation rules (no price, no fabricated presenter history), and the asynchronous id-return-with-polling contract. These are exactly the operational facts an agent needs before calling a costly mutation.

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?

Purpose is front-loaded, but the prose is dense and repetitive ('as the person asks, made again into a new video beside it, as the app's Change does'), and the credit/polling details are packed into the same paragraph. Every sentence carries information, but the wording taxes readability.

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 5-parameter, no-output-schema mutation tool, the description covers prerequisites, cost and refund, validation limits, and how to retrieve the result. It stops short of clarifying the 'part' parameter's role or what the returned id is for beyond polling, but nothing critical to correct invocation 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 coverage is 100%, so the baseline is 3, but the description adds meaning the schema does not: it explains that 'credits' must match the after_steps price (a different figure is refused) and constrains 'change' with the app's validation rules beyond the schema's 'in the person's words'. It still does not clarify the 'part' selector, which the schema handles.

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?

States a specific verb and resource: it changes one finished video into a new video alongside it, explicitly tied to the app's 'Change' operation. It also names its precondition ('Only for a video whose after_steps offers it') and its follow-up sibling (get_video), so an agent can separate it from make_video and list_videos. The phrasing is awkward and roundabout ('as the person asks, made again into a new video beside it'), which keeps it short of a 5.

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?

Gives an explicit eligibility condition ('Only for a video whose after_steps offers it') and the follow-up loop ('call get_video with it about once a minute until its status is ready or failed'). It does not name make_video or other alternatives as the when-to-use comparison, so it stops short of full alternative routing.

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