MCP 3D Printer Server

blender_mcp_export_stl

Export named Blender objects to a new, verified STL for slicing. Applies modifiers, writes world-space geometry without changing the scene, and reports triangle count and bounding-box dimensions.

Instructions

Export named objects from the live Blender scene to a new, verified STL for slicing. Writes world-space geometry with modifiers applied, without changing the scene, selection, or mode, and reports triangle count and bounding-box dimensions from the written file. Use this after editing or modelling through blender_mcp_call; Blender MCP's own export_scene writes GLB/FBX only. Requires standard Blender MCP and a shared local filesystem.

Input Schema

TableJSON Schema

Name	Required	Description
`scale`	No	Multiply coordinates before writing (default 1). Slicers read STL units as millimetres, so use 1000 for a scene modelled in metres.
`timeout_ms`	No	Total Blender request deadline in milliseconds; defaults to BLENDER_MCP_TIMEOUT_MS or 120000.
`output_path`	Yes	New local .stl path. Its parent must exist; existing files are never overwritten.
`user_prompt`	No	The user's own words, passed unchanged to Blender MCP.
`object_names`	Yes	Blender object names to export together as one STL (mesh, curve, surface, metaball, or text objects).
`apply_modifiers`	No	Export the evaluated geometry with modifiers applied (default true).

Schema Changelog

Changes observed during successful MCP inspections.

First observedv1.2.9Sep 29, 2026

TDQS

A4.7/5.0

Behavior5/5

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

With no annotations, the description carries the full burden and does so well: world-space geometry, modifiers applied, no mutation of scene/selection/mode, and a verification step reporting triangle count and bounding-box dimensions from the written file. This is exactly the side-effect profile an agent needs for a write-to-disk tool.

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?

Three dense sentences, front-loaded with the action and its guarantees, followed by usage routing and prerequisites. No filler and nothing that repeats structured fields verbatim.

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?

Despite the absence of an output schema, the description states what the caller gets back (triangle count and bounding-box dimensions) and covers prerequisites and non-destructive behaviour. Nothing needed to invoke it correctly is missing.

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%, so every parameter is already documented, including the mm-vs-metres scale rationale and the no-overwrite rule for output_path. The description adds no parameter meaning beyond that, which is the expected baseline 3 when the schema does the heavy lifting.

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?

States a specific verb and resource ('export named objects from the live Blender scene to a new, verified STL') and explicitly distinguishes itself from the sibling export path by noting that Blender MCP's own export_scene writes GLB/FBX only. An agent can select it without opening any schema.

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?

Gives an explicit trigger ('use this after editing or modelling through blender_mcp_call') and names the alternative that does not do this job. Prerequisites (standard Blender MCP, shared local filesystem) are also stated.

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

blender_mcp_export_stl

Instructions

Input Schema

Schema Changelog

TDQS

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