JANCTION Render

Read scene info

scene_info

Idempotent

Read a Blender scene without rendering (a few seconds, no GPU time): cameras and the active one, frame range and fps, resolution, objects by type, lights, materials, whether it is animated, and missing linked files that would render pink. Use it for a .blend you did not write, or to check what a bpy script built. Returns scene_id; pass it to render_preview and render_final instead of sending the scene again.

Input Schema

Name	Required	Description
`blender`	No	Blender version: '' (default: a .blend opens with the version it was saved in, other scenes with 5.0) or '5.0' / '5.2' (also '4.5', '4.2', '3.6'; a script that stops on Blender 5 because of an older API is rendered again on those automatically) to choose.
`scene_id`	No	scene_id returned by an earlier call (reuses the uploaded scene without sending it again).
`scene_url`	No	https link to a .blend, a .py script or a 3D file (.glb/.gltf/.fbx/.usd/.obj/.stl/.ply/.abc); the service fetches it (e.g. the sample https://render.janction.jp/samples/cube_scene.py, or a 12-hour /upload link). A .gltf or .obj also brings its .bin / .mtl / textures from the same folder.
`asset_urls`	No	Extra files sent with the scene: https links (textures, glTF .bin) or 'polyhaven:<id>' CC0 assets from asset_search ('polyhaven:<id>@2k' for 2k textures). A .blend finds them through relative paths (same folder); a script through os.environ['JR_ASSETS_DIR'] or the jr_assets helpers.
`scene_script`	No	The scene as bpy Python code (text). No file and no local Blender needed; the service runs it in Blender 5.0 (5.2 with blender='5.2'). Blender 5.0 API notes: materials are node-based, so set a colour on the Principled BSDF (mat.node_tree.nodes['Principled BSDF'].inputs['Base Color'].default_value = (r, g, b, 1)); mat.diffuse_color only affects the viewport; do not set Material.use_nodes. Animate with obj.keyframe_insert() (action.fcurves no longer exists; set bpy.context.preferences.edit.keyframe_new_interpolation_type = 'LINEAR' first for constant speed). Build the scene, camera and frame range only; leave resolution, samples and denoising to the service. Helpers: `import jr_assets`, then jr_assets.frame_camera(margin=1.1) points the camera at every object and fits them in the frame; jr_assets.import_model('<id>'), jr_assets.material('<id>') and jr_assets.world_hdri('<id>') use Poly Haven assets passed in asset_urls.

Output Schema

Name	Required	Description	Default
`result`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

Changed1 schema field changedOct 15, 2026

changedInput schema / properties / blender / description

Previous value: -"Blender version: '' (default: a .blend opens with the version it was saved in, other scenes with 5.0) or '5.0' / '5.2' to choose."New value: +"Blender version: '' (default: a .blend opens with the version it was saved in, other scenes with 5.0) or '5.0' / '5.2' (also '4.5', '4.2', '3.6'; a script that stops on Blender 5 because of an older API is rendered again on those automatically) to choose."

Changed1 schema field changedOct 14, 2026

changedInput schema / properties / scene_script / description

Previous value: -"The scene as bpy Python code (text). No file and no local Blender needed; the service runs it in Blender 5.0. Blender 5.0 API notes: materials are node-based, so set a colour on the Principled BSDF (mat.node_tree.nodes['Principled BSDF'].inputs['Base Color'].default_value = (r, g, b, 1)); mat.diffuse_color only affects the viewport; do not set Material.use_nodes. Animate with obj.keyframe_insert() (action.fcurves no longer exists; set bpy.context.preferences.edit.keyframe_new_interpolation_type = 'LINEAR' first for constant speed). Build the scene, camera and frame range only; leave resolution, samples and denoising to the service. Helpers: `import jr_assets`, then jr_assets.frame_camera(margin=1.1) points the camera at every object and fits them in the frame; jr_assets.import_model('<id>'), jr_assets.material('<id>') and jr_assets.world_hdri('<id>') use Poly Haven assets passed in asset_urls."New value: +"The scene as bpy Python code (text). No file and no local Blender needed; the service runs it in Blender 5.0 (5.2 with blender='5.2'). Blender 5.0 API notes: materials are node-based, so set a colour on the Principled BSDF (mat.node_tree.nodes['Principled BSDF'].inputs['Base Color'].default_value = (r, g, b, 1)); mat.diffuse_color only affects the viewport; do not set Material.use_nodes. Animate with obj.keyframe_insert() (action.fcurves no longer exists; set bpy.context.preferences.edit.keyframe_new_interpolation_type = 'LINEAR' first for constant speed). Build the scene, camera and frame range only; leave resolution, samples and denoising to the service. Helpers: `import jr_assets`, then jr_assets.frame_camera(margin=1.1) points the camera at every object and fits them in the frame; jr_assets.import_model('<id>'), jr_assets.material('<id>') and jr_assets.world_hdri('<id>') use Poly Haven assets passed in asset_urls."

Changed1 schema field changedOct 14, 2026

changedInput schema / properties / blender / description

Previous value: -"Blender version: '' (5.0, default) or '5.2' when the worker has it."New value: +"Blender version: '' (default: a .blend opens with the version it was saved in, other scenes with 5.0) or '5.0' / '5.2' to choose."

Changed5 schema fields changedOct 7, 2026

addedInput schema / properties / asset_urls / description

Added value: +"Extra files sent with the scene: https links (textures, glTF .bin) or 'polyhaven:<id>' CC0 assets from asset_search ('polyhaven:<id>@2k' for 2k textures). A .blend finds them through relative paths (same folder); a script through os.environ['JR_ASSETS_DIR'] or the jr_assets helpers."

addedInput schema / properties / blender / description

Added value: +"Blender version: '' (5.0, default) or '5.2' when the worker has it."

addedInput schema / properties / scene_id / description

Added value: +"scene_id returned by an earlier call (reuses the uploaded scene without sending it again)."

addedInput schema / properties / scene_script / description

Added value: +"The scene as bpy Python code (text). No file and no local Blender needed; the service runs it in Blender 5.0. Blender 5.0 API notes: materials are node-based, so set a colour on the Principled BSDF (mat.node_tree.nodes['Principled BSDF'].inputs['Base Color'].default_value = (r, g, b, 1)); mat.diffuse_color only affects the viewport; do not set Material.use_nodes. Animate with obj.keyframe_insert() (action.fcurves no longer exists; set bpy.context.preferences.edit.keyframe_new_interpolation_type = 'LINEAR' first for constant speed). Build the scene, camera and frame range only; leave resolution, samples and denoising to the service. Helpers: `import jr_assets`, then jr_assets.frame_camera(margin=1.1) points the camera at every object and fits them in the frame; jr_assets.import_model('<id>'), jr_assets.material('<id>') and jr_assets.world_hdri('<id>') use Poly Haven assets passed in asset_urls."

addedInput schema / properties / scene_url / description

Added value: +"https link to a .blend, a .py script or a 3D file (.glb/.gltf/.fbx/.usd/.obj/.stl/.ply/.abc); the service fetches it (e.g. the sample https://render.janction.jp/samples/cube_scene.py, or a 12-hour /upload link). A .gltf or .obj also brings its .bin / .mtl / textures from the same folder."

First observedOct 2, 2026

TDQS

A4.1/5.0

Behavior4/5

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

Annotations cover the safety profile, and the description adds genuine operational context: runtime and no-GPU cost, that missing linked files render pink, and that the call emits a reusable scene_id. It never explains why readOnlyHint=false (that the call uploads/materializes the scene), which is the one behavioral trait an agent might misread from 'Read'.

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?

Purpose is front-loaded in the first clause and every sentence carries weight. The long enumeration of returned fields is informative for selection but partly redundant given an output schema exists.

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?

With a rich schema, annotations, and an output schema, the description covers purpose, cost, usage conditions, and cross-tool chaining. The only uncovered element is the non-read-only nature implied by readOnlyHint=false, which the 'Read' framing leaves slightly ambiguous.

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 five parameters, including the scene_id reuse semantics. The description's note about passing scene_id to render_preview/render_final duplicates what the schema's scene_id description already states, adding no new parameter-level meaning. Baseline 3 applies.

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+resource ('Read a Blender scene') and enumerates exactly what is inspected (cameras, frame range/fps, resolution, objects, lights, materials, animation, missing linked files). It is plainly distinguishable from the render_* siblings because it explicitly says 'without rendering (a few seconds, no GPU time)'.

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?

Gives concrete when-to-use conditions: 'a .blend you did not write, or to check what a bpy script built', and names the downstream alternatives (render_preview, render_final) that consume its scene_id. It does not explicitly route away from siblings like scene_edit when mutation is intended, so no full when-not guidance.

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

All JANCTION Render tools Inspect

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