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

Annotations already declare readOnlyHint and openWorldHint, so the bar for added behavior context is lower. The description adds 'live' (suggesting real-time data) and 'fair-use limits' (implying quota awareness), which are useful behavioral disclosures beyond the annotations. No contradiction exists.

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 a single, compact sentence that front-loads the verb and clearly itemizes the output categories. Every word adds value, with no redundancy or filler.

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?

Given no parameters, no output schema, and a simple listing behavior, the description covers the essential information. It names all the capability categories returned, which is sufficient for a tool of this simplicity. It does not describe the response structure, but that is not critical for a capabilities list.

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?

The tool has zero parameters, and the schema coverage is 100% (trivially). Baseline for zero parameters is 4. The description does not need to compensate for missing schema details, and it appropriately describes what the tool lists.

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 clearly states the tool's function with a specific verb 'List' and explicitly enumerates the resource categories (canvas formats, fonts, layouts, image models, GPU reachability, fair-use limits). This distinguishes it from sibling tools which are all action-oriented (design, edit, render, etc.).

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?

The description implies usage as a discovery/preflight tool (e.g., to check available formats or limits before other operations), but it does not explicitly state when to use it or mention alternatives. No exclusions or contextual triggers are provided, leaving usage mostly implicit.

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