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, its name, and the list position used.

Inputs

Input	Type	Default	Description
`mode`	combo	`fixed`	How the role is chosen: `fixed`, `increment`, or `random`. See Selection modes below.
`role`	combo	first role	Role used in `fixed` mode. The list is built from `roles/*.md` at startup. Add a `.md` file and restart ComfyUI to add a role.
`index`	INT	`0`	Position used in `increment` mode. Set its `control_after_generate` to increment to advance one role per generation. Wraps within `start..end`.
`seed`	INT	`0`	Seed used in `random` mode. Set `control_after_generate` to randomize for a new pick each generation; the same seed reproduces the same role.
`start`	INT	`0`	Lower bound position (0-based) into the alphabetically sorted role list.
`end`	INT	`-1`	Upper bound position; `-1` means the last role. Out-of-range values are clamped.

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.
`resolved_index`	INT	The list position actually used. Useful for logging or labelling batched runs.

Selection modes

Roles are sorted alphabetically by display name; start/end index into that list (0-based, end = -1 means the last). The range is inclusive.

fixed: output the role dropdown. index/seed/start/end ignored.
increment: output the role at start + (index mod span), wrapping back to start after end. Set the index widget's control_after_generate to increment so each generation advances to the next role.
random: output a role picked from start..end using seed. The same seed always yields the same role; set control_after_generate to randomize for a fresh pick per run.

Note: control_after_generate is the same per-widget control ComfyUI puts on the seed widget of samplers. Increment/random still work without it by changing index/seed yourself or by using ComfyUI's batch count.

Adding roles

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.
The dropdown label defaults to the prettified filename: summarizer.md becomes Summarizer.
To set an explicit label, make the first line of the file an HTML comment:
```

```
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.)
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 25 passing tests (title parsing, filename prettify, label-collision disambiguation, path-traversal rejection, missing-file error, edit hot-reload, bad-encoding tolerance, range bounds/clamp/swap, increment wrap, random determinism, mode selection, shipped-role discovery).

In ComfyUI

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.
Add the node, pick a role and mode, and wire system_prompt into your LLM node.
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.

Support

If you find this useful, please consider starring the repo. Stars help other people discover these nodes.