nx_list_faces

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

With no annotations, the description carries safety disclosure and explicitly adds 'Read-only', which is meaningful for an inspection tool. It also discloses a non-obvious output nuance: normal is reported only for planar faces. It does not cover invalid body_id or empty-body behavior, but this is a minor gap for a read-only listing operation.

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?

Single purpose-built sentence, front-loaded with the verb and resource, followed by a bullet-like list of returned fields and the read-only flag. No 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?

The output schema covers return value structure, and the description enumerates the returned face attributes, so an agent can predict the call's behavior. It omits prerequisites such as needing an open part or a valid body_id from nx_list_bodies, but the omission is unlikely to cause incorrect invocation.

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?

The only parameter is `body_id`, and although the schema gives no description, the phrase 'of a body' ties the parameter directly to the resource being inspected. For a single self-descriptive identifier this is sufficient compensation for the 0% schema coverage.

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 action ('Inspect'), a clear resource ('every face of a body'), and enumerates the exact data returned. This makes it immediately distinguishable from siblings such as nx_list_edges, nx_list_bodies, and nx_list_features.

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 makes the intended use obvious (face inspection) but does not explicitly state when to prefer it over alternatives or mention that edge/body/sketch listing has separate tools. The when-to-use is implied by scope, not stated as guidance.

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