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mpfb_get_face_units

Read-onlyIdempotent

Read the live ARKit face unit values applied to a MakeHuman character's face in Blender, including optional zero values, without changing anything.

Instructions

Read the ARKit face units currently applied to a MakeHuman character's face - the live !ex- shape key values mpfb_set_face_units writes. Changes nothing.

result's face_units is one entry per face unit: face_unit (the bare ARKit name, e.g. "jawOpen"), value, and shapekey_present - whether a real shape key backs this value or MPFB is reporting a default for a unit that has never been touched. Defaults to the non-zero units only; include_zero (default false) returns all 52.

known_face_units is always present regardless of whether a subject resolves: every legal name mpfb_set_face_units will accept, grouped by facial region (brow, eye, cheek, jaw, mouth, nose, tongue) the way MPFB's own composer panel lays out its sliders.

faceunits01_installed is always present too, and is the one thing that separates "a neutral face" from "the faceunits01 asset pack was never installed" - both read as every unit at 0.0, and MPFB itself gives no other way to tell them apart. That check is cached for the Blender session; refresh (default false) busts the cache, which matters if the pack was installed after this Blender started.

A subject that cannot be resolved to a basemesh is an answer, found: false with a sentence, not an error; basemesh_name names the object the answer was actually read from.

Input Schema

TableJSON Schema
NameRequiredDescriptionDefault
nameNo
refreshNo
include_zeroNo

Output Schema

TableJSON Schema
NameRequiredDescriptionDefault

No arguments

Schema Changelog

Changes observed during successful MCP inspections.

  1. First observedv0.1.0

TDQS

A4.6/5.0
Behavior5/5

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

Annotations already declare readOnly/idempotent/non-destructive, and the description adds substantial context beyond them: read values are cached for the Blender session, unresolved subjects return found:false rather than an error, and faceunits01_installed disambiguates 'neutral face' from 'pack not installed'. This is rich behavioral disclosure.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Purpose is front-loaded, then structured paragraphs cover the result shape, always-present fields, and the found:false semantics. Dense but each sentence carries information; slightly verbose in places but not wasteful.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness5/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a read tool with three optional params and an output schema, the description covers return fields, defaults, error-vs-answer semantics, cache behavior, and region groupings. Nothing an agent needs to call it correctly is missing.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 0%, so the description must carry parameter meaning. It explains include_zero (default false -> all 52) and refresh (default false, busts the session cache) well; name is only implied via 'a subject that cannot be resolved', which is a minor gap.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The first sentence states a specific verb (Read) and resource (ARKit face units on a MakeHuman character's face), and explicitly frames it as the read counterpart to mpfb_set_face_units. An agent can distinguish it from siblings without opening the schema.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

It names the counterpart write tool and gives conditions for the two flags (refresh when the pack was installed after Blender started; include_zero for all 52 units). It does not exclude scenarios explicitly, but the context is clear enough for correct selection.

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