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

Annotations already declare non-read-only, non-idempotent, non-destructive, closed-world behavior. The description adds real context on top: the call is paid from the user's credits, and a call that got no answer may already have started, which warns against duplicate charging. It still doesn't say what is returned (e.g. a new photo id) or whether the source photo is altered.

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?

Three sentences, front-loaded with the core action, then geometry, then pricing and retry safety. Dense and largely waste-free, though the clause 'the photo's prices from get_shoot or list_photos name it' is awkwardly inverted.

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?

Covers cost, frame geometry and the non-idempotent retry hazard, which is most of what a credit-spending mutation needs. Since there is no output schema, the missing piece is what the tool produces or how the new photo is identified, which the description never mentions.

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?

With 0% schema coverage the description must carry the load, and it does for the geometry: x, y, w are fractions of the photo from 0 to 1 representing left edge, top edge and width, with the largest frame centred when omitted. max_credits is explained as the agreed price and photo_id as one of the user's photos; ratio is only alluded to as 'the given shape' and is left to the enum.

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 precise verb and resource: cuts a frame of a given shape from one of the user's photos and upscales it to a full photo. That is materially more specific than the title and separates it from plain upscale, but it never explicitly names upscale/edit/reroll as the alternatives, so sibling differentiation is only implicit.

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 concrete routing guidance: prices to pass as max_credits come from get_shoot or list_photos, and a retry should be preceded by a list_photos check. It does not state when to prefer this over upscale or reroll, which is the remaining gap.

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