mcp-fabric-api

variable_library_get_definition

Read-only

Retrieves the full definition of a variable library by writing variables.json, settings.json, valueSets, and .platform files to a specified directory. Returns the list of written files.

Instructions

Get the definition of a variable library (long-running). Writes all definition files (variables.json, settings.json, valueSets/*.json, .platform) to the specified output directory and returns the list of files written.

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": {
      "workspaceId": "<workspaceId>",
      "variableLibraryId": "<variableLibraryId>",
      "outputDirectoryPath": "<outputDirectoryPath>"
    },
    "name": "variable_library_get_definition"
  }
}

Input Schema

Name	Required	Description
`workspaceId`	Yes	The workspace ID
`variableLibraryId`	Yes	The variable library ID
`outputDirectoryPath`	Yes	Directory path where definition files will be written

Schema Changelog

Changes observed during successful MCP inspections.

First observedv2.8.0Sep 6, 2026

TDQS

A4/5.0

Behavior4/5

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

The description adds useful behavioral context beyond the readOnlyHint/destructiveHint annotations by noting the operation is long-running, writes specific files to a local output directory, and returns a list of files written. The local write does not contradict readOnlyHint since it does not mutate the Fabric resource.

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 compact and front-loaded: it states the action and long-running nature first, then gives the concrete side effects and return value. Every sentence contributes useful information with no filler.

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?

For a tool with three simple parameters, no output schema, and read-only annotations, the description covers the essential behavior, output, and side effects well. It could be more complete by explaining how to handle the long-running aspect, such as polling or timeout expectations, but it is sufficient for correct selection and invocation.

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 coverage is 100%, so the schema already documents all three parameters adequately. The description reinforces that outputDirectoryPath receives the definition files and lists the expected file names, but it adds little parameter meaning beyond what the schema provides.

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 states a specific action and resource: getting the definition of a variable library. It also explains the unique behavior of writing definition files to an output directory and returning the written file list, which clearly distinguishes it from variable_library_get and variable_library_update_definition.

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 implies when to use this tool: when a caller needs the full definition files exported to a directory. However, it does not explicitly say to use variable_library_get for simple metadata retrieval or update_definition for modifications, and it offers no exclusions or alternative routing.

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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