cozyvtt-mcp

Character Validate

character_validate

Read-onlyIdempotent

Retrieve validation diagnostics for an owned character to see if it passes upstream checks. Understand that a 'valid' result may be unreliable and does not guarantee saved data.

Instructions

Read upstream validation diagnostics for an owned character with a fixed gameSystem. Use character_get to inspect fields; do not use this as a reliable save gate. v1.4.0 ignores validation failures, so isValid=true does not prove validity; older-version reliability is unknown. Always adds validation_reliable=false and validation_note. Owner-only upstream read; repeating it does not repair or save data. Returns {ok:true,data} on success; tool-body failures return {ok:false,error} with optional diagnostic data. Argument-schema errors are MCP errors.

Input Schema

TableJSON Schema

Name	Required	Description	Default
`character_id`	Yes	Existing character ID owned by the authenticated user; fixed-system validation is required upstream.

Output Schema

TableJSON Schema

Name	Required	Description	Default
No arguments

Schema Changelog

Changes observed during successful MCP inspections.

Changed1 schema field changedv0.3.0Sep 20, 2026

addedInput schema / properties / character_id / description

Added value: +"Existing character ID owned by the authenticated user; fixed-system validation is required upstream."

First observedv0.1.0Sep 5, 2026

TDQS

A4.6/5.0

Behavior5/5

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

The annotations already indicate read-only, idempotent, and non-destructive behavior, and the description adds valuable context beyond that: version-specific validation reliability, the guaranteed addition of validation_reliable and validation_note, and the exact success/error return shapes. There is no contradiction with the annotations.

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?

The description is front-loaded with purpose and usage, then covers reliability caveats and return behavior. It is a bit dense, but every sentence earns its place by conveying risks and edge cases that an agent needs before calling.

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 single-parameter read-only tool with rich annotations and an output schema, the description is complete. It covers ownership, reliability caveats, success versus failure shapes, and MCP-level argument-schema errors, leaving no critical gap.

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

Parameters3/5

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

The input schema fully documents character_id at 100% coverage, so the baseline is 3. The description reinforces that the character must be owned and that validation is fixed-system, but it does not add meaningfully new parameter-level semantics beyond the schema.

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 opens with a specific verb and resource: 'Read upstream validation diagnostics for an owned character.' It also distinguishes itself from character_get by explicitly routing field inspection to that sibling, so an agent can tell the tools apart.

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

Usage Guidelines5/5

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

The description gives explicit guidance: use character_get to inspect fields and do not rely on this tool as a save gate. It also clarifies that repeating the call does not repair or save data, which helps an agent decide when not to invoke it.

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