v1.8.0 — Tools from other plugins

Tools from other plugins

Other Blockbench plugins can now give Claude new tools. One call adds a tool and it shows up in Claude's tool list right away:

const tool = BlockbenchMCP.registerTool({
  name: 'model_report',
  description: 'Summarise the open model: bones, cube counts, textures, animations.',
  inputSchema: { type: 'object', properties: { bone: { type: 'string' } } },
}, (args) => ({ project: Project.name /* ... */ }));

tool.delete(); // removes it again

• The tool also appears on relay instances, and disappears on delete() or when Blockbench closes.
• Listen for the blockbench_mcp_ready event to register again after the bridge plugin reloads.
• The server does not check arguments against inputSchema; validate them in the handler.

See Adding tools from another plugin.

Also in this release

• Shorter errors. When a tool handler throws, Claude gets only the message, without the plugin bundle's stack frames (266 → 57 characters for a typical error). The Blockbench console still logs the full error.
• Java force_translucent. create_texture and import_texture take force_translucent: true for Java block/item models. The exported JSON writes the texture as {"sprite": "...", "force_translucent": true}. Needs Blockbench 5.2.2. On older versions you get a clear error, and nothing is changed.

Tested on Blockbench 5.2.2:

• verify-plugin-api 12/12, smoke and e2e tests pass.
• A tool registered from Blockbench was listed, called and removed in a live Claude Code session.
• force_translucent was exported and reopened from a Java block model, and the flag was kept.
• Blockbench 5.2.2 fixes that reach our tools were checked with real models:
  • IK bake on pre-rotated bones, and undo/redo of the bake
  • Vertex weights kept by merge_meshes
  • glTF UVs on multi-texture, non-power-of-2 models
  • FBX export of a mesh with a stray vertex

Installation

1. Download blockbench_mcp.js and mcp-server.js (or unzip the archive). No npm install needed: the server is bundled with its dependencies.
2. Blockbench → File → Plugins → Load Plugin from File → blockbench_mcp.js.
3. Add it to Claude:

claude mcp add --scope user blockbench -- node /path/to/mcp-server.js

Requires Node.js 18+.

Updating

1. Overwrite both files with the new ones.
2. Restart Blockbench.