measure_stems

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

With no annotations, the description carries the full burden. It usefully discloses the ray-casting technique and the returned measurement categories, but it never explicitly states that the operation is read-only/non-destructive or how it behaves for missing glyphs, invalid master_id, or unusual outlines.

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?

The description is compact and well-structured: purpose, algorithm, returned values, workflow guidance, and examples are all present without fluff. The extra detail is justified by the absence of a schema description and output schema.

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?

It is sufficient for a basic call with just glyph_name, and it outlines the return categories despite having no output schema. However, optional parameters like samples and master_id remain undefined, and units or exact output formatting are not disclosed, leaving gaps for more nuanced usage.

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%, and the description only clarifies glyph_name through examples. samples and master_id are not explained at all beyond their schema types and defaults, so the agent must guess their meaning and impact on the results.

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 begins with a specific verb and resource: 'Measure stem thicknesses in a glyph using ray-casting,' and it clarifies vertical versus horizontal stems. It is clearly a measurement tool distinct from compare-focused siblings like compare_stems, though it never explicitly names alternatives.

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?

It gives a concrete workflow instruction: use this BEFORE and AFTER applying RMX filters to verify the effect. It also provides natural-language examples, but it does not explain when to prefer compare_stems or other stem-analysis tools instead.

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