game_center_challenge_images_update_instance

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

No annotations are provided, so the description carries the full behavioral burden, and it discloses almost nothing: no auth/permission requirements, no indication of which fields are updatable or whether the update is partial versus full replacement, and no note on side effects. Pointing at the OpenAPI schema for the body envelope is the only substantive disclosure.

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 short, but it wastes its limited space: the identical PATCH path is printed twice in parentheses, and the body-shape hint duplicates the schema's own description. Front-loading the route is fine, but the redundancy means not every sentence earns its place.

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 mutation tool with a nested JSON:API body, two required parameters, no annotations, and no output schema, this description is too thin. It never explains what a valid GameCenterChallengeImageUpdateRequest contains or what the caller gets back, so an agent cannot invoke it correctly without going outside the definition.

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% (both 'id' and 'body' are described in the schema), so the baseline is 3. The description adds nothing beyond what the schema already says, merely repeating the OpenAPI component name for the body shape, so it neither compensates for nor improves on the schema.

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 echoes the route 'PATCH /v1/gameCenterChallengeImages/{id}', which does convey the verb (partial update) and the resource (a Game Center challenge image). However, it is a mechanical restatement of the tool name rather than a plain-language statement of what changes, and it offers no differentiation from sibling update tools such as game_center_challenge_localizations_update_instance or the leaderboard/achievement image updaters.

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?

There is no guidance on when to use this tool versus game_center_challenge_images_get_instance, _create_instance, or _delete_instance, nor any mention of prerequisites (e.g., the image must already exist). The agent is left to infer usage entirely from the HTTP verb.

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