vnyan-mcp

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VNyan expressions

vnyan_expression

List, read, export, and import Expression Mapper entries mapping input blendshape windows to forced output values. Export to .vnexp; import adds/replaces by name and needs VNyan closed.

Instructions

Expression Mapper entries: input blendshape value windows (AND-gated, case-insensitive match) that force output blendshape values when all inputs are in range. 'list'/'read' (disk, always readable) read settings.json 'Expressions'. 'export' writes one entry out as a standalone .vnexp JSON file. 'import' reads a .vnexp file and adds/replaces it by name in settings.json - REQUIRES VNyan closed, same guard as vnyan_settings_set.

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "action": "<action>"
    },
    "name": "vnyan_expression"
  }
}

Input Schema

Name	Required	Description
`name`	No	Expression name (required for read/export)
`path`	No	.vnexp file path (required for import/export)
`action`	Yes	Which expression operation to perform

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.0Jul 29, 2026

TDQS

A3.8/5.0

Behavior4/5

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

With no annotations provided, the description carries the full burden. It discloses that list/read are disk reads, always readable; export writes a file; import adds/replaces by name and requires VNyan closed. It also explains the internal structure of expressions (input windows, AND-gating). The guard reference for import adds useful context. Minor omissions: no mention of permissions or side effects beyond file writes.

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 highly concise, using two sentences to explain the core concept and then a list-like format for actions. It front-loads the essential idea of an expression mapper entry and avoids redundancy. Every sentence adds unique information, with no wasted words.

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

Completeness3/5

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

Given the tool has 3 parameters, no output schema, and moderate complexity, the description covers the data model and each action's purpose. However, it lacks details on return values (e.g., what list returns, format of read output) and error conditions. For a tool with no output schema, describing the return structure would improve completeness.

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 100% with all parameters described. The description adds significant value beyond the schema: it clarifies that 'name' is the expression name used for read/export, 'path' is a .vnexp file path for import/export, and elaborates on each action's effect (e.g., 'export' writes a standalone .vnexp file, 'import' reads and adds/replaces). This extra context aids correct parameter usage.

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 defines the tool as dealing with 'Expression Mapper entries' and explains the core concept (input blendshape value windows that force outputs). It lists and describes each action (list, read, export, import) with specific behavior. While it does not explicitly differentiate from siblings, the unique resource and actions make the purpose distinct.

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

Usage Guidelines3/5

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

The description provides usage context for each action: list/read are 'always readable' and read from settings.json, export writes a standalone .vnexp file, import requires VNyan closed and is guarded like vnyan_settings_set. However, it does not specify when to prefer this tool over alternatives (e.g., vnyan_settings_get/set) or when not to use it, limiting guidance.

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