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nmassi

glyphs-mcp

by nmassi

rmx_scale

Scale glyphs by percentage width or height while preserving stroke weight via RMX Scaler. Adjust weight, spacing, and vertical shift for precise type modifications.

Instructions

Scale a glyph by percentage in width and/or height.

USE THIS for percentage-based scaling requests like "make 30% wider".

RECIPE: For a multi-glyph scaling task, call get_recipe("scale_proportions") first and follow it step by step.

Uses RMX Scaler with stroke-weight compensation via master interpolation. Native affine fallback is opt-in because it cannot preserve stem weight. Response includes a "method" field: "rmx" = RMX Scaler was used, "native_transform" = affine transform fallback.

Args: glyph_name: Name of the glyph to scale width: Width scale as percentage. 100 = no change, 130 = 30% wider, 70 = 30% narrower height: Height scale as percentage. 100 = no change weight: Stroke weight delta (RMX only, ignored in native fallback) adjust_space: Sidebearing adjustment delta vertical_shift: Vertical position offset master_id: Optional active master ID. RMX still processes all masters. allow_fallback: Permit native affine scaling if RMX fails. Default False.

RMX parameters accept either one value for every master or a list in
font master order for independent per-master control.

Examples: "Make R 30% wider" → rmx_scale("R", width=130) "Make R 20% narrower" → rmx_scale("R", width=80) "Scale R to 90% height, keep width" → rmx_scale("R", height=90)

Input Schema

TableJSON Schema
NameRequiredDescriptionDefault
widthNo
heightNo
weightNo
master_idNo
glyph_nameYes
adjust_spaceNo
allow_fallbackNo
vertical_shiftNo

Schema Changelog

Changes observed during successful MCP inspections.

  1. First observedv0.3.0

TDQS

A4.3/5.0
Behavior4/5

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

No annotations exist, so the description carries the full burden. It discloses the use of RMX Scaler with stroke-weight compensation, the opt-in native affine fallback and its limitation, the fact that RMX processes all masters even when master_id is set, and the response's method field. It does not state whether the operation modifies in place or returns a new glyph, which prevents a 5.

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

Conciseness5/5

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

Despite its length, the description is well-structured: a one-sentence purpose, a highlighted usage directive, a recipe hint, a concise behavior note, a bulleted Args section, and examples. Every sentence conveys necessary information with no filler, appropriate for a tool with 8 parameters.

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

Completeness4/5

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

Given 8 parameters, no annotations, and no output schema, the description is nearly complete: it explains all params, the method field, fallback semantics, and provides examples. It lacks only explicit statement of whether the glyph is edited in place or returned as a new object, and how errors are surfaced, which would make it fully complete.

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

Parameters5/5

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 entirely. It does: every one of the 8 parameters is documented with meaning and, for width/height, concrete percentages (100 = no change, 130 = 30% wider). It also explains list semantics for per-master control and provides example invocations. This is exemplary compensation.

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

Purpose4/5

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

The description clearly states a specific verb, resource, and scope: 'Scale a glyph by percentage in width and/or height.' It also gives canonical examples. However, it does not explicitly differentiate itself from the sibling smart_scale, which could plausibly perform scaling too, so it falls short of a 5.

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?

The description gives explicit when-to-use guidance: 'USE THIS for percentage-based scaling requests like "make 30% wider"'. It also provides a recipe instruction for multi-glyph tasks and explains the fallback behavior. It does not name alternatives or exclusions, so it is not a full 5.

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