raycast

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

With no annotations, the description carries the full behavioral burden. It usefully states that the ray runs in world space and returns the first hit, distance, point, and normal, but omits critical behavior such as what happens on a miss, whether non-mesh objects are ignored, and how max_distance limits 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?

Two tightly packed sentences with no filler. The core action and return payload are front-loaded, and the usage sentence follows immediately, so every sentence earns its place.

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 no annotations, no output schema, and 0% schema description coverage, the description covers the return payload and use cases but leaves significant gaps: max_distance semantics, no-hit behavior, and parameter vector formats are all absent. An agent could call it, but with avoidable guesswork.

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. 'World space' clarifies the coordinate frame for origin and direction, but max_distance is never mentioned and no vector format or units are specified, leaving a required parameter and a key optional parameter unexplained.

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 and resource ('Shoot one ray in world space') and describes what it returns, so the agent can distinguish it from general measurement or mapping tools. It does not explicitly name or contrast with siblings like line_of_sight, so sibling differentiation is only implicit.

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 explicit use cases ('find floors, ceilings, wall thickness and free space'), giving clear context for when to reach for this tool. It stops short of naming alternatives such as line_of_sight or viewshed, so the when-not condition 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.