production.facial_render_closeup

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

Beyond the annotations, the description discloses substantial behavioral traits: the facial reference is an immutable plan.json, candidates are new Actions evaluated through NLA tracks and the body Action is never modified, and speech requires explicit timed phonemes (TIMING_INPUT_REQUIRED otherwise). These are concrete mutation-safety and failure-mode details the annotations alone (readOnly=false, destructive=false) do not 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?

Every sentence carries information, but the opening restates the tool name and the rest is dense jargon (M7, NLA, TIMING_INPUT_REQUIRED) strung together without clear ordering. The most important fact — what the tool renders — never appears.

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 not be explained, but the description omits the tool's actual output/concept and leaves five of seven parameters undefined in a tool with 0% schema coverage. For a non-idempotent mutation-adjacent render tool, that leaves real gaps.

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 for all seven parameters. It explains only 'apply' (default false) and 'facial' (immutable plan.json reference); brief, intent, options, object_name, and operation_id are left entirely undocumented.

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?

The description repeats the name ('facial_render_closeup: M7 facial unit') and then talks entirely about workflow and constraints (plan-first, candidates, NLA tracks) rather than stating what the tool actually produces — presumably a closeup render/preview of a facial setup. It never distinguishes itself from the sibling facial_render_preview, so an agent cannot tell the two apart from the text.

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?

'plan first, apply=false by default' gives sequencing guidance and 'Technical QA and artistic review stay separate' implies this tool does not perform review. But there is no explicit statement of when to use this instead of facial_render_preview or facial_review, so usage is only implied.

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