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

Goes well beyond the annotations (destructiveHint=true) by disclosing the coin cost model, the confirmation-threshold flow, the confirmation_token mechanics, the returned task id and the follow-up tool, and that unlimited-plan allowances do not apply. The request_id charge-idempotency note adds context the annotations cannot express.

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?

Front-loaded with the core action, then cost and confirmation flow, then return/follow-up. The final two sentences ('charged in VerseIn coins', 'unlimited-plan allowances do not apply') partly restate the earlier 'Spends the user's coins' line, a small redundancy that keeps it from a 5.

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 an 11-parameter generative mutation with an output schema, the description covers the essentials: cost and approval gating, token round-trip, and what to do after the call (get_tasks). Return-value detail is correctly left to the output schema.

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 73%, so the schema already documents aspect_ratio, prompt, max_total_coins, confirmation_token and request_id in detail. The description reinforces the confirmation_token and cost workflow but adds little about the placement coordinates (x_start/x_end/y_start/y_end) or resolution that is not already in the schema; baseline 3 applies.

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 (reframe / change aspect ratio) and resource (a video, a VerseIn media URL) plus the distinctive behavior of filling new areas with generated content. This separates it clearly from edit_video, extend_video and upscale_video without needing to open any schema.

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 clear operational guidance: prices depend on length, above-threshold calls return needs_confirmation with a token, the user must be asked, then the call is repeated with the token, and the task is followed via get_tasks. It does not explicitly state when to pick this over edit_video, so it falls short of a 5.

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