hive-blender

A host-neutral IAddon for the Blender MCP add-on's base command catalog and loopback socket. The built-in export_scene supports GLB and FBX only; STL requires a separately authorized execute_code operation and an installed Blender STL exporter. No native 3MF export is claimed.

Running

Install and enable the reference Blender MCP addon.py in a GUI Blender instance, on the same host as hive-blender. Set BLENDERMCP_NO_UPDATE_CHECK=1 in Blender's environment before launching to disable the add-on's network update check. The direct socket path never imports its Python MCP server; hive-blender makes no telemetry, update, Premium or cloud provider calls. Do not enable optional provider integrations in the baseline. Blender is not installed in the current test environment; tests use an in-process fake add-on server, not verified against a real Blender. Restrict access to the loopback listener: the reference add-on has no socket authentication and other local processes can send it commands directly.

Configure the addon in hive-mcp's config.edn under :addons:

{:addons {"hive.blender"
          {:port 9876
           :code-gate {:max-bytes 200000
                       :deny-substrings ["import os" "subprocess" "requests" "urllib"
                                         "premium" "telemetry" "polyhaven" "sketchfab"
                                         "hyper3d" "tripo" "open("]
                       :require-confirm true}}}}

The addon refuses to mount without a valid :code-gate. Alternatively, a host can inject a hive-blender.port/CodeGate record under that key. The data policy requires a positive :max-bytes of at most 200000 UTF-8 bytes, a nonempty case-insensitive substring deny-list, and :require-confirm true; it cannot accept regular expressions or executable policy code. execute_code always requires :confirm true and gate approval. The gate is a policy hook, not a Python sandbox. On socket timeout the typed :blender/unknown-outcome means a mutation might already have run; never replay it automatically. Every call uses a fresh socket, closed after reply or error, one outstanding command per socket. Configure socket time/size bounds via socket-link; the destination is hardwired to IPv4 loopback, default port 9876.

The tool offers catalog, doctor and call; optional provider handlers are not catalogued. Scene and object references are values containing file identity and names, not bpy pointers. See native seams for deployment limits and unanswered questions.

Run clojure -M:test and dev/verify_portability.sh for the fake-server conformance and JVM/cljw/cljrs/cljs portable codec checks. The GPL bambu-printer-mcp bridge is used for interoperability facts only; redistributing or requiring it from an MIT addon needs a separate licensing decision.

License: MIT.