production.facial_analyze_eyes

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

Annotations only declare the mutation profile (readOnlyHint=false, idempotentHint=true, destructiveHint=false); the description adds real value beyond them by stating that apply defaults to false, that the body Action is never modified, that candidates land in new Actions evaluated via NLA tracks, and that missing phoneme timing yields TIMING_INPUT_REQUIRED. The unexplained "M7"/NLA vocabulary is the main 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?

Front-loaded and dense with no filler, but it is a run-on chain of domain jargon ("M7", "NLA tracks", "TIMING_INPUT_REQUIRED") that is never unpacked, so the compression costs comprehension rather than saving it.

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?

An output schema exists, so return values need no explanation, but the description omits what the eye analysis actually evaluates and leaves four of six parameters undefined. For a six-parameter tool at 0% schema coverage, this is materially incomplete.

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% across six parameters, so the description must carry the load, but it only clarifies two: `apply` (default false, plan-first) and `facial` (immutable plan.json reference). `brief`, `intent`, `options`, and `object_name` receive no explanation anywhere.

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?

"facial_analyze_eyes: M7 facial unit" mostly restates the tool name with an internal module label; it never says what is actually analyzed about the eyes or what output the analysis produces. Nothing distinguishes it from close siblings such as facial_analyze_eyelids, facial_analyze_asymmetry, or facial_analyze_shape_keys.

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 gives workflow rules ("plan first, apply=false by default", "Speech needs explicit timed phonemes/visemes") but no guidance on when to choose eyes analysis over the other facial_analyze_* tools or what prerequisite state must exist. An agent must guess its place in the facial analysis sequence.

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