LLM Set Role - Custom node for ComfyUI

A single node that presents a dropdown of LLM roles (system prompts) and outputs the selected role's text as a STRING. Wire that STRING into the system_prompt input of an LLM node (Ollama, etc.) to give the model a consistent role: a style transform, a summarizer, a translator, a captioner, an editor, anything you can write as a system prompt.

The node will be located under Add Node > LLM. Node name: Set Role.

Designed to pair with LLM nodes such as the stavsap/comfyui-ollama pack: this node supplies the system prompt, the LLM node does the generation.

The problem it solves

Multi-stage prompt pipelines reuse the same long system prompts. Pasting that prose into a text box on every workflow is error-prone and hard to keep consistent. This node keeps each role as a Markdown file on disk and exposes them as a dropdown, so a workflow picks a role by name and the exact, version-controlled text flows into the LLM. Modes let you also step or randomize through your roles across a batch.

Nodes included

• Set Role - dropdown of roles from roles/*.md, outputs the selected role text and its name.

Inputs

Input	Type	Default	Description
role	combo	first role	The role to output. The list is built from roles/*.md at startup. Add a .md file and restart ComfyUI to add a role. Use the widget's control after generate to step through roles across a batch (see below).

Outputs

Output	Type	Description
system_prompt	STRING	The full text of the selected role file, ready to wire into an LLM node's system_prompt input.
role_name	STRING	The selected role's display name, e.g. for logging or filename suffixes.

Stepping through roles

The role dropdown carries ComfyUI's control after generate control, the same one on a sampler's seed widget. It steps the dropdown after each generation, so a batch walks your roles natively, with role names shown (no index numbers):

• fixed: stay on the selected role.
• increment wrap: advance to the next role each generation and wrap back to the first after the last (Role 0 -> 1 -> ... -> 0). Pick this to cycle through your roles.
• decrement: step backwards.
• randomize: pick a random role each generation (may repeat).

Tip: plain increment (without "wrap") stops at the last role instead of cycling; use increment wrap to loop.

Adding roles

1. Drop a new .md file into the roles/ directory. The file content is the system prompt, kept verbatim. See roles/example.md.example for the format.

2. The dropdown label defaults to the prettified filename: summarizer.md becomes Summarizer.

3. To set an explicit label, make the first line of the file an HTML comment:

   <!-- title: Concise Summarizer -->
   

   That line is stripped from the output and is used only as the dropdown label. (An HTML comment is used rather than a # heading because role files commonly start with their own # heading.)

4. Restart ComfyUI so the new file appears in the dropdown. Editing an existing role does not need a restart: the node re-runs when the file changes.

Your roles/*.md files are gitignored, so your prompts stay private and local. The shipped roles/example.md.example is tracked only as a format reference and is not loaded by the node.

Usage

[Set Role].system_prompt -> [Ollama Generate].system_prompt
your prompt text         -> [Ollama Generate].prompt

Testing

Unit tests (no ComfyUI needed)

cd ComfyUI_LLMSetRole
python -m unittest test_set_role -v

Expect 15 passing tests (title parsing, filename prettify, label-collision disambiguation, path-traversal rejection, missing-file error, edit hot-reload, bad-encoding tolerance, shipped-role discovery).

In ComfyUI

1. Restart ComfyUI so the node loads. Confirm it appears once under Add Node > LLM as Set Role, with no import error in user/comfyui.log.
2. Add the node, pick a role (and optionally set its control after generate), and wire system_prompt into your LLM node.
3. Run the workflow. The LLM node receives the selected role text.

Installation

ComfyUI Manager (recommended)

In ComfyUI, open Manager > Custom Nodes Manager, search for ComfyUI_LLMSetRole, click Install, then restart ComfyUI.

Manual install

Clone into your ComfyUI custom_nodes directory and restart ComfyUI:

cd ComfyUI/custom_nodes
git clone https://github.com/bradsec/ComfyUI_LLMSetRole

No extra dependencies (Python stdlib only).

Compatibility

Dual API: exports the legacy V1 NODE_CLASS_MAPPINGS and a V3 comfy_entrypoint (comfy_api). On builds whose loader reads NODE_CLASS_MAPPINGS first, the V1 path is used and comfy_entrypoint is skipped, so the node is never registered twice.

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Support

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