build_ellipsoid

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

With no annotations provided, the description carries full burden. It clearly indicates this is a creation/mutation tool ('Build an ellipsoid'), but doesn't disclose important behavioral traits like whether it overwrites existing blocks, requires specific permissions, has rate limits, or what happens on failure. The example helps but doesn't cover behavioral aspects.

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?

The description is appropriately sized with three sentences that each earn their place: stating the purpose, providing use cases, and giving an example. It's front-loaded with the core functionality. Could be slightly more concise by combining some concepts, but overall efficient.

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 9-parameter creation tool with no annotations and no output schema, the description provides adequate purpose and context but lacks important behavioral information. It doesn't explain what the tool returns, error conditions, or mutation implications. Given the complexity and lack of structured safety information, more completeness would be helpful.

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?

With 100% schema description coverage, the baseline is 3. The description adds some value by explaining that different radii create unique shapes and providing an example with specific values, but doesn't add significant semantic meaning beyond what's already well-documented in the schema descriptions for each parameter.

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 tool builds an ellipsoid structure, specifying it's a stretched/oval sphere. It distinguishes from siblings like build_sphere by emphasizing different radii create unique shapes, and provides concrete use cases (egg shapes, stretched domes, oval rooms, artistic sculptures).

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 provides clear context for when to use this tool (for egg shapes, stretched domes, oval rooms, artistic sculptures) and distinguishes it from build_sphere by mentioning different radii. However, it doesn't explicitly state when NOT to use it or mention specific alternatives among siblings like build_hyperboloid or build_paraboloid.

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