Font Design MCP

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font_validate

Run technical font validation: compile TTF, inspect tables and corpus coverage, and receive errors, warnings, and observations.

Instructions

Run technical checks, compile a TTF, inspect tables and corpus coverage. Reports errors, warnings and observations; does not assess artistic merit.

Input Schema

TableJSON Schema

Name	Required	Default
`corpus`	No
`detail`	No	summary
`revision`	No
`project_id`	Yes

Output Schema

TableJSON Schema

Name	Required	Description	Default
`ok`	Yes
`data`	No
`error`	No
`changed`	No
`summary`	Yes
`revision`	No
`warnings`	No
`project_id`	No

Schema Changelog

Changes observed during successful MCP inspections.

Changed14 schema fields changedv0.4.3Sep 9, 2026
- removedInput schema / properties / corpus / title
```
Removed value: -"Corpus"
```
- addedInput schema / properties / detail
```
Added value: +{
+  "default": "summary",
+  "enum": [
+    "summary",
+    "full"
+  ],
+  "type": "string"
+}
```
- removedInput schema / properties / project_id / title
```
Removed value: -"Project Id"
```
- removedInput schema / properties / revision / title
```
Removed value: -"Revision"
```
- removedInput schema / title
```
Removed value: -"Validate"
```
- removedOutput schema / properties / changed / title
```
Removed value: -"Changed"
```
- removedOutput schema / properties / data / title
```
Removed value: -"Data"
```
- removedOutput schema / properties / error / title
```
Removed value: -"Error"
```
- removedOutput schema / properties / ok / title
```
Removed value: -"Ok"
```
- removedOutput schema / properties / project_id / title
```
Removed value: -"Project Id"
```
- removedOutput schema / properties / revision / title
```
Removed value: -"Revision"
```
- removedOutput schema / properties / summary / title
```
Removed value: -"Summary"
```
- removedOutput schema / properties / warnings / title
```
Removed value: -"Warnings"
```
- removedOutput schema / title
```
Removed value: -"Result"
```
First observedv0.1.0Sep 8, 2026

TDQS

B3.1/5.0

Behavior3/5

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

Annotations are minimal (all hints false), so the description carries the behavioral burden. It discloses that it compiles a TTF, inspects tables, and reports errors/warnings/observations. However, it does not clarify whether the compiled TTF is persisted, whether any project state is modified, or what side effects occur. The 'compile' action implies potential file creation, but the description is vague about persistence. It also doesn't mention permissions or reversibility. This is partial transparency.

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?

The description is two sentences with no wasted words. It front-loads the primary actions (run checks, compile, inspect) and adds the reporting scope and the artistic merit exclusion. Every clause earns its place. It is compact and readable.

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

Completeness2/5

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

The tool has 4 parameters, an output schema, and complex behavior (compilation, inspection). The description is far too sparse to be complete. It does not explain parameter usage, when to use it versus font_build, or what the output report includes beyond errors/warnings/observations. Even though an output schema exists, the description should still clarify the tool's role and parameter semantics. The missing guidance leaves significant gaps for an agent.

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

Parameters1/5

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

Schema description coverage is 0% and the description provides essentially no parameter-level semantics. It mentions 'corpus coverage' which alludes to the corpus parameter but does not explain it, nor does it explain detail (summary vs full), revision, or the purpose of project_id beyond the obvious. With zero coverage, the description must compensate by explaining each parameter, and it fails to do so. The agent is left to guess what these parameters control.

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 description clearly states the verb 'Run technical checks', the resource (a font/project via project_id), and specific actions: compile a TTF, inspect tables and corpus coverage. It also explicitly differentiates by stating it does not assess artistic merit, which distinguishes it from render or edit tools. The purpose is unambiguous and well-scoped.

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

Usage Guidelines2/5

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

The description provides no explicit guidance on when to use this tool versus alternatives. It mentions 'technical checks' but does not name sibling tools like font_build or render_glyph, nor does it state conditions for choosing this over them. The 'does not assess artistic merit' hint is too implicit to serve as a routing rule. An agent would have to infer when to invoke this tool.

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