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

Annotations already disclose destructiveHint=true, openWorldHint=true, and non-idempotent behavior, so the safety profile is covered. The description adds only the mild constraint that time of day and extra instructions are the sole optional controls, and says nothing about generation being asynchronous, cost, or how to retrieve results (despite a get_generation sibling). Nothing in the text contradicts the 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?

Two sentences, front-loaded with the trigger condition and free of filler. The second sentence is slightly oblique ('workspace controls') but is short and purposeful.

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 output schema and rich image schema relieve the description of explaining inputs and returns. However, for a generative, non-idempotent, open-world tool, the description says nothing about generation time, whether a job id comes back, or that results are fetched separately, which an agent needs to sequence the call correctly.

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 100%, and the schema already spells out time_of_day options and the 'do not ask when the request is clear' guidance for additional_instructions. The description's line about 'the only optional workspace controls' restates that framing rather than adding new meaning. Baseline 3 applies when the schema carries the semantics.

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 gives a specific transformation: 'an interior sketch, model view, or design image turned into a photorealistic architectural render.' The 'interior' qualifier implicitly separates it from render_exterior, but no sibling is named explicitly, so the agent must infer the contrast from the sibling list.

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?

The opening 'Use when the user wants...' clause is a clear trigger condition tied to input type (sketch, model view, design image). It does not state exclusions or point to alternatives such as change_room_style, virtual_stage_room, or render_exterior, so routing between close siblings still requires inference.

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