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

Beyond the annotations, the description discloses that the operation is paid from the user's credits, that pricing must be pre-agreed and bounded by max_credits, and that a call may already have started even when no answer came back. That async/partial-execution warning is behavior the annotations (readOnlyHint false, idempotentHint false) cannot express, and it directly guards against duplicate charges.

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?

It is front-loaded with the core action and packs constraints, pricing, and retry guidance without filler. The pricing sentence is somewhat tangled ('the photo's prices from get_shoot or list_photos name it'), which costs a point on readability but not on economy.

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 credit-consuming, non-idempotent generation tool with no output schema, the description covers cost, input constraints, and how to recover results after a failed or silent call (check list_photos). It never states what a successful call returns or how long results take, which is the remaining gap.

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 0%, so the description carries the full burden, and it does: photo_id as the target person's photo, with_photo_id as the garment source (and its exclusion rules), part as an optional top/bottom selector, and max_credits as a price ceiling with a stated source. Every parameter gets meaning the bare schema lacks.

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 names a specific verb and resource ('Puts the clothes another of the user's photos shows ... on the person in one of their photos') and scopes the 'part' option to top or bottom only. This clearly distinguishes it from sibling tools such as combine, edit, or replace_background.

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?

It gives concrete preconditions: with_photo_id may not be a selfie and may not equal photo_id, and max_credits must match the price the user agreed to, sourced from get_shoot or list_photos. It also tells the agent what to do after an unanswered call. It stops short of naming an explicit alternative tool for cases where these conditions fail, so it falls just 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.