R3

Save a .blend as a version of a Blender model

r3_blender_upload

Save a .blend you made or changed (in Blender, through a Blender MCP) as the newest version of one of the user's Blender models: the model is named by the file name, so "monster-truck.blend" adds a version to the user's monster-truck model, or makes the model. A tool argument cannot carry the file, so this answers a one-time upload ticket (5 minutes) and the upload endpoint: its URL, method, Authorization header and that the body is the file's raw bytes. Sending it needs file access where the .blend is (the R3 sandbox, or the user's own machine); without it, the user uploads on the Blender page. The endpoint's answer names the model, the version number and its sha256; R3 applies unapplied modifiers itself, and when the user's projects use an older version it asks one question (answer it with r3_blender_update). Then r3_blender_import puts the model in a project. Textures travel only when packed (bpy.ops.file.pack_all()). Up to 100 MB. Needs the blender:upload right.

Input Schema

Name	Required	Description	Default
`fileName`	Yes	The .blend file name, which names the model: "monster-truck.blend" (".blend" is added when missing). A name only, no folder.

Output Schema

Name	Required	Description
`url`	Yes
`body`	Yes
`answer`	Yes	This answer in words: what was done, what R3 measured, decided or refused, and what to do next. The same text as the result's text block. Read it: the fields beside it are the data, this is the guidance.
`method`	Yes
`ticket`	Yes
`headers`	Yes
`fileName`	Yes
`maxBytes`	Yes
`expiresAt`	Yes
`environment`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

Changed4 schema fields changedOct 16, 2026

addedOutput schema / properties / body
```
Added value: +{
+  "type": "string"
+}
```

removedOutput schema / properties / curl

Removed value: -{
-  "type": "string"
-}

addedOutput schema / properties / headers

Added value: +{
+  "additionalProperties": false,
+  "properties": {
+    "Authorization": {
+      "type": "string"
+    }
+  },
+  "required": [
+    "Authorization"
+  ],
+  "type": "object"
+}

changedOutput schema / required

Previous value: -[
-  "ticket",
-  "url",
-  "method",
-  "curl",
-  "expiresAt",
-  "maxBytes",
-  "environment",
-  "fileName",
-  "answer"
-]New value: +[
+  "ticket",
+  "url",
+  "method",
+  "headers",
+  "body",
+  "expiresAt",
+  "maxBytes",
+  "environment",
+  "fileName",
+  "answer"
+]

AddedOct 16, 2026

TDQS

A4.6/5.0

Behavior5/5

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

Beyond the annotations, it discloses a one-time 5-minute upload ticket, the endpoint URL/method/Authorization header and raw-bytes body, the need for file access, the 100 MB limit, the required blender:upload right, and the packed-texture caveat. These are exactly the behavioral details an agent needs and are consistent with openWorldHint=true, idempotentHint=false, and destructiveHint=false.

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 purpose is front-loaded and nearly every sentence carries operational value, including ticket handling, file access, size limit, rights, and follow-up tools. It is dense and somewhat run-on, but the length is justified by the complexity of the upload workflow.

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?

Given a one-parameter but multi-step upload workflow with annotations and an output schema, the description covers prerequisites, ticket/endpoint mechanics, file-access alternatives, size limits, rights, texture packing, and follow-up tools. Nothing essential for correct invocation appears to be 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?

The single fileName parameter is fully documented in the schema, including the 'name only, no folder' constraint and the automatic .blend suffix. The description reinforces the model-naming consequence but adds little beyond the schema, so the high schema coverage sets the baseline at 3.

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 (save a .blend) and resource (newest version of a Blender model), and explains the naming convention that links the file to the model. It is easily distinguishable from siblings like r3_blender_import and r3_blender_update because it describes the upload/versioning step.

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?

It gives explicit conditions for use: after making or changing a .blend in Blender or a Blender MCP, and it names the fallback when file access is unavailable (user uploads on the Blender page). It also routes the agent to r3_blender_update for an older-version question and to r3_blender_import for placing the model in a project.

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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