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

Annotations already establish this as a safe read-only, non-open-world query, so the bar is lower; the description still adds the return contract ({ used, limit, remaining, plan, unlimited }) and the key edge case that remaining is null when unlimited. It does not cover freshness/latency or whether the monthly window resets on a fixed date.

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?

Two sentences, zero filler: purpose and the ordering constraint come first, the return shape second. Every clause 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?

With no output schema, the description compensates by enumerating the returned fields and the null-when-unlimited semantics, which is exactly the information an agent needs to interpret the result. Nothing material is missing for a one-parameter read tool.

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 100% and the single uuid-constrained projectId is fully documented in the schema, so the baseline is 3. The description only implies the quota is project-scoped ('the project's') without adding format or acquisition guidance beyond what the schema provides.

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 (check) and resource (project's monthly AI image-generation quota), with clear scope. It is trivially distinguishable from siblings like generate_image and get_image_job without opening any schema.

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 positions itself as a pre-flight check: 'before calling generate_image', which routes the agent to the correct sequencing relative to a sibling. It stops short of stating exclusions or failure modes (e.g. what to do if remaining is 0).

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