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

With no annotations, the description carries the transparency burden. It discloses the return payload, the scale rendering, the photo limitation ('Roomproof does not render photos'), and the key requirement. It does not explicitly claim the operation is side-effect-free, but 'Returns' plus the absence of mutation language is meaningful.

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 with no filler. The main return value is front-loaded, and the following sentence supplies the most important usage caveats: photo handling, the key requirement, and the free example project.

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 tool with one required parameter naturally derived from the schemacing flow und no output schema, the description covers the return artifact, the intended use of image_prompt, and the authentication prerequisite. An agent has enough to decide when to call it and what to pass.

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?

All three parameters are already documented in the schema, giving 100% schema coverage, so the baseline is 3. The description reinforces the key exception for beispiel-wohnzimmer but adds no new parameter semantics beyond what the schema already states for project and variant.

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 first sentence names a concrete action and resource: it returns 'the saved plan as an image drawn to scale, plus image_prompt and image_positions.' This clearly distinguishes the tool from siblings like open_plan and check_plan by describing its specific output artifact, though it never explicitly contrasts itself with those siblings.

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 description gives practical context about when a key is needed and how to use the image_prompt for photos, which implies usage. However, it does not explicitly say when to prefer show_plan over open_plan or check_plan, and it lacks any when-not-to-use guidance.

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