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

The description discloses that credits are spent and that the operation returns a job id for asynchronous polling, which is critical behavioral information beyond the readOnly/destructive hints. No contradiction with annotations.

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?

A single, focused sentence with no redundant words. All key points (purpose, cost, async pattern) are conveyed efficiently.

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 simple generation job, the description covers the essential workflow: what is generated, that it costs credits, and how to retrieve the result. It lacks parameter-level detail, but that is partially addressed by the schema.

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 50% (location_id and idempotency_key have descriptions, user_notes and reference_image_asset_ids do not). The tool description adds no parameter-specific detail beyond implying location_id is the target location, so it does not compensate for the missing parameter docs.

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 action ('Generate a reference image') and the target resource ('a location'), distinguishing it from sibling generation tools like generate_character_image and generate_shot_background_image.

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 practical usage context by warning about credit consumption and directing the user to poll with get_job. It does not explicitly contrast with alternative tools, but the credit and polling guidance is actionable.

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