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

Annotations already mark this read-only and closed-world, so the description focuses on what the agent cannot infer: the asynchronous 'when ready' state, the exact return contents, the one-hour URL expiry, and the fact that the call is free. URL expiry is a genuinely valuable trait not in the 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?

Three short sentences, status first, return payload second, cost note last. No repetition of the name or title and nothing that could be cut without losing information.

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 carries the return-value burden and does so (fields plus URL lifetime). It leaves unstated what a not-ready response looks like and how to poll, which is a small but real gap for an async job-status 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 both parameters are documented, including that project_id comes from split_into_layers. The description only implies the async-wait semantics through 'When ready' and adds nothing about how wait_seconds interacts with that state, so baseline 3 applies.

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 what the tool returns: split status plus every layer with name, position, and a PNG download URL. That is a concrete verb+resource picture. It does not distinguish itself from siblings like unlock_layers or get_credits, but the primary purpose is unambiguous.

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?

No guidance on when to call this versus unlock_layers, nor any mention of the polling pattern (call after split_into_layers, retry if not ready). The word 'Free' hints at a cost model but does not route the agent between alternatives.

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