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node-opcua

node-opcua-modeler-mcp-server

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by node-opcua

opcua_model_validate

Validate OPC UA YAML models for correctness, returning diagnostics with severity, codes, messages, and line numbers. Use before generating to catch errors.

Instructions

Validate an OPC UA YAML model for correctness. Returns diagnostics with severity (error/warning/info), codes, messages, and line numbers. Works without an API key (limited to 50 calls/day). ALWAYS validate before generating.

Input Schema

TableJSON Schema
NameRequiredDescriptionDefault
yamlYesThe full YAML model source to validate
Behavior4/5

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

No annotations are provided, so the description carries the full burden. It discloses the rate limit (50 calls/day) and indicates the tool returns diagnostics with severity, codes, messages, and line numbers. This suggests a read-only validation operation, which is adequately transparent.

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 three sentences: clear purpose, key behavioral note (rate limit), and imperative usage hint. Every sentence adds value; no wasted words.

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 the tool has one parameter, no output schema, and no annotations, the description sufficiently explains the input, output (diagnostics with specific fields), and a notable constraint (rate limit). It could mention output format more explicitly, but overall it's complete for a validation tool.

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?

Schema description coverage is 100% for the single parameter 'yaml', which is described as 'The full YAML model source to validate'. The description adds no additional semantics beyond what the schema already provides, so baseline 3 is appropriate.

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 tool validates an OPC UA YAML model for correctness, using a specific verb and resource. This distinguishes it from sibling tools like opcua_model_generate or list_namespaces, which have different purposes.

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 explicitly says 'ALWAYS validate before generating', providing clear when-to-use guidance. It also notes the tool works without an API key (50 calls/day limit), giving context on availability. It does not explicitly state when not to use, but the sibling context implies alternatives.

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

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