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Dawn-Of-Justice

Fusion Native MCP

fusion_execute_python

Execute Python scripts within Autodesk Fusion to automate modeling, assembly, CAM, and inspection tasks. Supports idempotent operations and read-only mode for safe scripted control.

Instructions

Run Python defining run(context) inside Fusion. Supports all installed API namespaces.

Mutations require document id from fusion_inspect and a unique operation_id. Repeat the same id/request to retrieve its prior result without executing again. Exceptions may leave partial changes. Inspect results separately; succeeded means the script returned, not that geometry or machining correctness was verified. Script code is trusted local code, not sandboxed. Use explicit units in scripts.

Input Schema

TableJSON Schema
NameRequiredDescriptionDefault
scriptYes
read_onlyNo
operation_idNo
expected_document_idNo

Schema Changelog

Changes observed during successful MCP inspections.

  1. First observedv0.2.0

TDQS

A4.7/5.0
Behavior5/5

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 exceptions may leave partial changes, that 'succeeded' only means the script returned without verification, that script code is trusted local code not sandboxed, and that explicit units are required. These are critical behavioral traits that fully inform an agent of the risks and semantics.

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 but information-dense, with the core purpose first, followed by essential caveats and requirements. Every sentence adds value—no filler or redundancy. The line breaks contribute to scannability without excessive length.

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 tool that executes arbitrary Python code with potential side effects, the description covers the critical aspects: prerequisite document id and operation_id, idempotency semantics, partial-change behavior, interpretation of 'succeeded', security implications, and unit guidance. Given the lack of an output schema and annotations, this is remarkably complete.

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 description coverage is 0%, so the description must compensate. It explains operation_id (unique for mutations, repeatable for retrieval) and expected_document_id (implied as the document id from fusion_inspect). It also gives guidance for the script parameter via 'Use explicit units'. read_only is not directly explained, but the mutation context strongly implies its role. The description adds meaningful meaning 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 clearly states the verb 'Run' and the resource 'Python defining run(context) inside Fusion', with the additional scope of supporting all installed API namespaces. This is specific and distinct from sibling tools like fusion_create_feature or fusion_set_parameter, which target specific operations rather than arbitrary script execution.

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 provides explicit usage context: mutations require a document id from fusion_inspect and a unique operation_id, and repeating an id retrieves the prior result. It also warns that success does not imply geometry correctness. While it does not explicitly contrast with alternative tools or state when not to use it, the conditions for mutations and the idempotency pattern are clear enough for an agent to decide.

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