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

Goes well beyond annotations by disclosing the state transition (QUEUED -> CANCELED), the billing consequence ('nothing is charged'), and that out-of-scope items are silently left untouched rather than erroring. It also pre-announces the response shape (canceled / skipped) despite there being no output schema.

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 a [write] marker and the core action, then narrows to scope, exclusions, and return values. Dense and largely waste-free, though the long run-on enumeration of creator tools and the parenthetical album example make it heavier than necessary.

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 destructive annotation and no output schema, the description covers what is affected, what is protected, cost implications, and the returned counts. An agent has everything needed to call it correctly; only the multi-selector edge case is left open.

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 0% with no property descriptions, so the description must carry the load – and it does, explaining that image_id/image_uuid target one picture while images_album_uuid targets a whole album ('e.g. a storyboard: all its queued pictures'). It does not clarify mutual exclusivity or what happens when multiple selectors are supplied, and all three params are technically optional.

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 ('Cancel pictures queued by create_character_image / ...') and enumerates the exact upstream tools whose output it can cancel. This is far more precise than a generic 'cancel image' and lets an agent distinguish it from creation/regeneration siblings.

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?

Explicitly states the precondition (worker_images_characters has not started) and the excluded states: 'A picture already being drawn (PROCESS) or finished (DONE | FAILED) cannot be stopped and is left as it is.' It gives solid when/when-not guidance but never names the nearby sibling cancel_character_queue or explains how they differ.

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