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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint, covering the safety profile. The description goes beyond these by disclosing the specific return semantics: 'Returns 0 when batching is not supported' and the recommended fallback action. This adds behavioral context that annotations do not provide.

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, efficient sentence with two clauses: the core action and the special-case behavior. No filler, and the most important information (what the tool returns) is front-loaded before the conditional note.

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 parameterless getter, this is complete. It explains the primary purpose, the semantic meaning of the return value in cases where batching is unsupported, and provides a fallback instruction. The output schema presumably defines the exact response shape, so no further explanation is needed.

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 input schema has zero parameters, and schema description coverage is 100% (since there are no params to cover). The description appropriately does not need to add parameter details. Baseline for 0-parameter tools is 4, and nothing here lowers that.

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 states a specific action ('Get'), a clear resource ('maximum number of images that can be created in a single batch'), and the scoping ('according to the user's plan'). It clearly distinguishes from sibling create_batch_images, which actually creates batches, by focusing on the limit rather than creation.

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 provides actionable guidance for the 0-return case, instructing the agent to 'create images individually instead,' which implicitly tells when to avoid using the batch-creation sibling. It doesn't explicitly name the sibling tool or state 'use this before create_batch_images,' but the conditional fallback is a clear usage signal.

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