place_on

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

No annotations, so the description carries the full burden, and it does disclose the core mechanism (raycast-style drop, lowest point of object + children, first hit, world-xy fallback). It omits edge cases such as behavior when nothing is hit and whether the move is reversible, which for an unannotated mutation tool is a modest gap.

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 tight sentences: mechanism first, then use cases, then the alternative-selection routing. Every sentence earns its place with no repetition of the schema.

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 4-param, no-annotation, no-output-schema tool, the description covers behavior and sibling routing well. It leaves minor gaps around yaw_deg semantics and failure modes, but an agent can call it correctly from this text.

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 0%, so the description must compensate. It clarifies the `at` parameter's role (world xy fallback anchor) and implies what `surface` selects, but `yaw_deg` and the `object`/`surface` formats are never explained. Partial compensation only.

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 (drop/place) and resource (object with children onto a surface) plus the exact placement rule: lowest point lands on the first hit under it, or under world xy `at`. This is clearly distinguishable from siblings like ground, attach, and scatter, which are named.

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?

Explicit when-to-use (props on tables, floors with height changes, terrain) and explicit alternatives with their distinguishing conditions: ground for level floors at known height, attach to align by bounding boxes, scatter for many copies. Nothing is left to inference.

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