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

Annotations already declare destructiveHint=true, openWorldHint=true, idempotentHint=false, and readOnlyHint=false. The description adds no behavioral context beyond the purpose: it does not say what image content is altered, whether changes are reversible, or that repeated calls may produce different results.

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 tightly scoped sentence with the usage trigger front-loaded. There is no redundant or wasted wording.

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?

The tool has five nested parameters and is a destructive image-editing operation, yet the description never states that a room image is the core input or how reference images and additional instructions are used. The rich schema and output schema reduce the burden, but selection and invocation context is still thin.

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 80%, and the schema already documents the image, reference image, and additional_instructions fields in detail. The description adds no meaning beyond the schema, so the baseline of 3 is appropriate.

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-plus-resource scenario: filling a pool with clean water and tidying the surrounding area. The resource is unique among the sibling tools, though the description does not explicitly contrast itself with alternatives such as custom_prompt.

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?

Provides a clear triggering condition with 'Use when the user wants a pool filled with clean water and the surrounding pool area tidied.' It gives clear context but no when-not guidance or explicit routing to alternative tools.

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