2026-07-16

Blender MCP Joins the Hermes Agent MCP Catalog With a Curated 4-Tool Surface

hermesmcpblenderpluginscatalog

Teknium announced on July 15 that the Blender MCP is now part of the Hermes Agent MCP Catalog. Users can install it with a single command:

hermes mcp install blender

The announcement generated 995 likes, 81 retweets, and 617 bookmarks on X, with 77 replies in the thread. Behind the tweet, the integration landed as a cluster of three PRs totaling 1,004 additions across 12 files, all merged on July 15.

What the catalog entry ships

The Blender MCP catalog entry (#64463, 196 additions, 4 files) defines a new manifest at optional-mcps/blender/manifest.yaml. The default install exposes four core tools:

Tool	What it does
`get_scene_info`	Returns the current Blender scene structure, object names, and hierarchy
`get_object_info`	Returns detailed properties for a specific object by name
`get_viewport_screenshot`	Captures the current 3D viewport as an image
`execute_blender_code`	Runs arbitrary bpy Python code inside the Blender Python context

The remaining 18 tools from ahujasid/blender-mcp involve third-party asset services (PolyHaven, Sketchfab, Hyper3D, Hunyuan3D). These are not enabled by default. Users who want them can opt in via hermes mcp configure blender. The tools.default_enabled field in the manifest handles this without any upstream changes to the MCP server itself.

The same PR added transport.env support to the catalog's config builder (hermes_cli/mcp_catalog.py, +19/-1). Manifests can now declare static environment variables for the subprocess. The Blender entry uses this to set DISABLE_TELEMETRY=true, following the project's no-telemetry-without-opt-in policy. Three new tests validate that env blocks are parsed, written to the server config, and that absent env leaves no env key for existing entries.

Skill rework: from raw socket to catalog tools

A companion PR (#65066, +168/-136, 3 files) rewrote the optional blender-mcp skill to route through the catalog entry instead of teaching the agent to open a raw TCP connection to the Blender addon's socket on port 9876.

The old approach had the agent writing its own Python socket helper and talking JSON directly to the addon. This bypassed the catalog entirely - no version pinning, no tool curation, no install-time validation. The new skill's prerequisites section starts with hermes mcp install blender and the interaction surface is the four curated MCP tools. The raw-socket section was removed and replaced with an explicit anti-pattern note.

The skill also kept alireza78a's existing bpy recipe collection (materials, keyframes, render-to-file, scene setup) and added new pitfalls: using Xvfb for headless Blender, the --no-sandbox flag, remote-host path resolution, and recovery when expected MCP tools are missing.

Community reference library salvaged from #10908

The third PR (#65116, +640/-4, 5 files) cherry-picked kshitijk4poor's reference library from PR #10908 - a community contribution that had been building reference material against the raw-socket approach. Rather than discard the work, teknium1 adapted it to the new MCP-tool surface:

File	Lines
`references/bpy-api.md`	264
`references/recipes.md`	223
`references/pitfalls.md`	133
Total salvaged	620

The pitfalls file was rewritten to drop all references to the raw blender_exec() socket helper and TCP internals, while keeping every bpy-specific finding: empty code results in Blender 5.x, the temp-file readback pattern, ops-vs-data context rules, engine names by version, and GPU setup details. The recipes file had one blender_exec call updated to execute_blender_code. Original authorship was preserved with kshitijk4poor's commit cherry-picked intact and kshitijk4poor added to the skill's author list.

What this means for the catalog pattern

The Blender MCP integration is the third entry in the MCP catalog after n8n and Linear. It also introduces two new capabilities to the catalog system itself:

Curated tool defaults. Catalog entries can now restrict which server tools are registered on install (tools.default_enabled), while letting users opt into additional tools through hermes mcp configure. The Blender entry uses this to gate 18 service-dependent tools behind a configuration step.
Transport environment variables. Manifests can declare static transport.env entries. The runtime already supported per-server env vars - manifests just had no way to declare them. This was needed for telemetry policy and will apply to any future entry that needs to ship with static environment configuration.

Both features are baked into the catalog's config builder and tested alongside existing entries (n8n and Linear configs verified byte-identical before and after).

The full catalog is browsable via hermes mcp catalog list. The Blender entry shows up under official/blender with the curated 4-tool surface.

[^1]: Teknium on X. "The Blender MCP is now part of the Hermes Agent MCP Catalog!" July 15, 2026.

[^2]: teknium1. "feat(mcp): add Blender to the MCP catalog with a curated 4-tool default." Hermes Agent PR #64463. Merged July 15, 2026.

[^3]: teknium1. "refactor(skills): rework blender-mcp skill around the catalog MCP entry." Hermes Agent PR #65066. Merged July 15, 2026.

[^4]: teknium1. "feat(skills): salvage blender-mcp reference library from #10908 onto the MCP-tool skill." Hermes Agent PR #65116. Merged July 15, 2026.