Read the ground frame

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

Annotations already declare readOnlyHint=true, so the safety profile is covered externally. The description's added value is the conditional-absence warning, which discloses that missing numbers are intentional and must not be hallucinated as heights — a genuinely useful behavioral trap that annotations cannot convey.

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, both load-bearing: the first states the operation, the second carries the crucial absence warning. The warning is front-loaded right after a short lead, and there is zero filler.

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 one-parameter, read-only tool with no output schema, the description covers the main failure mode an agent would otherwise hit: inventing heights when the frame is intentionally absent. The only omission is the return shape or units of the frame, which is minor given the readOnlyHint and the simplicity of the call.

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% — scan_id is only typed as a string with no description — and the description never mentions the parameter. The name is predictable among scan-scoped siblings, but the description does not compensate for the coverage gap, leaving the agent to guess the ID's format or provenance.

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 ('Read') and resource ('recorded floor/ceiling frame'), and pins it to the GET /ground_frame endpoint. The reading semantics implicitly separate it from the related sibling scene_ground_frame_fit, whose name signals computation or fitting rather than retrieval. An agent can tell this tool apart from its closest alternative without opening either schema.

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 an explicit conditional — 'If vertical_axis_known is false... say so rather than guessing heights' — telling the agent how to behave when the frame lacks data. It does not explicitly name alternatives like scene_ground_frame_fit, but the recorded-vs-fit distinction and the endpoint make the intended use context reasonably clear.

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