| name | comfyui-prompt-engineer |
| version | 1.1.1 |
| description | Crafts checkpoint-specific ComfyUI prompt pairs (FLUX, SDXL, SD1.5, Wan, AnimateDiff) with matching negatives, CFG ranges, and identity-method rules (InstantID, PuLID, FaceID, Kontext, character LoRA). Use when generating or adapting prompt text for a known model stack. Not for interviewing a vague idea (comfyui-prompt-interview), wiring node-graph JSON (comfyui-workflow-builder), or installing/launching ComfyUI (comfyui). |
| risk | safe |
| source | openrouter-deepsearch |
| date_added | 2026-06-16T00:00:00.000Z |
Overview
Generates optimized prompts tailored to a specific model and identity method. Diffusion checkpoints do not share a prompt language. Each family was trained with a different text encoder on a different caption distribution, so the same sentence lands differently depending on the target. This skill picks the rules that match the checkpoint and the identity-preservation method actually in the stack.
When to Use
Activate this skill when the job-to-be-done is crafting or refining the prompt text for a ComfyUI generation. Triggers on requests to:
- Generate a new positive/negative prompt pair for a specific checkpoint (FLUX, SDXL, SD1.5, Wan, AnimateDiff)
- Refine or debug an existing prompt that is underperforming on a given model
- Adapt a prompt when switching checkpoints (e.g., an SDXL prompt that needs to run on FLUX)
- Tailor a prompt to an identity method (InstantID, PuLID, IP-Adapter FaceID, FLUX Kontext, character LoRA)
- Build a model-appropriate negative prompt
- Recommend a CFG range that matches the model + identity-method stack
- Include the correct trigger word and feature handling when a character LoRA is in play
Prerequisites
- ComfyUI installed and target checkpoint identified.
- Character profile available at
projects/{project}/characters/{name}/profile.yaml (if using a character LoRA or specific identity).
- Optional: the Examples section below for fuller prompt pairs; the model-rule tables in Procedure for CFG ranges. This skill crafts prompt text for a known checkpoint — it does not interview a vague idea (use
comfyui-prompt-interview for that).
Procedure
1. Identify Target Model and Identity Method
Determine the checkpoint family (FLUX, SDXL, SD1.5, Wan, AnimateDiff) and the identity method (InstantID, PuLID, IP-Adapter FaceID, FLUX Kontext, Character LoRA) in use.
2. Load Character Profile
If using a character LoRA or specific identity, read the character profile from projects/{project}/characters/{name}/profile.yaml to get the trigger word and canonical feature list. Do not invent details.
3. Apply Model-Specific Rules
FLUX.1 (dev / schnell / Kontext)
- Style: Natural-language descriptions. FLUX uses a T5-XXL text encoder alongside CLIP and parses sentences rather than comma-separated booru tags.
- CFG: 3.5–4 (very low) for
dev; schnell runs near CFG 1. High CFG over-saturates color and "fries" the image.
- Quality tags: Minimal. Strings like
masterpiece, best quality add token noise.
- Negative prompts: Keep short. Guidance-distilled FLUX barely responds to a negative branch.
- Length: Medium (50–100 words).
- Structure:
{subject description}, {setting}, {lighting}, {camera/style}.
SDXL (RealVisXL, Juggernaut XL, DreamShaper XL, etc.)
- Style: Quality tags at the front help significantly. SDXL has two CLIP text encoders trained on quality-rated captions.
- CFG: 7–9. Needs real guidance pressure; below ~6 it looks washed out, above ~10 it over-saturates.
- Quality tags: Include
masterpiece, best quality, photorealistic.
- Length: Medium-long (50–150 words).
- Structure:
{quality tags}, {trigger word}, {subject}, {details}, {setting}, {style}.
- Weighted syntax: Supported, e.g.
(important:1.3). Keep weights modest (1.1–1.4).
SD 1.5
- Style: Tag-based. Community SD1.5 checkpoints are heavily booru/tag trained.
- CFG: 7–8.
- Quality tags: Essential.
- Length: Shorter (30–80 words). Hard 77-token window; anything past it is truncated.
- Structure:
{quality}, {trigger}, {subject}, {details}, {style tags}.
Wan 2.1 / 2.2 (Video)
- Style: Concise motion descriptions. The sampler animates whatever action you describe.
- CFG: 5–7.
- Quality tags: Minimal.
- Length: Short (20–50 words).
- Focus: Describe the motion, not just the appearance.
- Structure:
{subject}, {action/motion}, {setting}, {quality}.
AnimateDiff
- Style: Same as the base model (SD1.5 or SDXL) for content. Add explicit camera and subject motion keywords.
- Length: Same as the base model.
4. Apply Identity-Method Modifiers
Do not re-describe in text what the method already injects.
- InstantID: Injects identity through a ControlNet-style face branch. DO NOT describe specific facial features. Describe clothing, pose, setting, lighting. Keep CFG at 4–5.
- PuLID: Lighter identity-injection. Can include minimal facial descriptions. CFG 5–7. Use "fidelity" mode to lock closer to reference.
- IP-Adapter FaceID: Encodes reference face into an image-prompt embedding. Describe the style you want, not the face. Use base model's standard CFG.
- FLUX Kontext (Editing): Instruction-conditioned editing model. Describe the EDIT, not the full image. Be specific about what to change and what to preserve.
- Character LoRA: Fine-tuned weights bound to a trigger word. ALWAYS include the trigger word first. Don't describe features the LoRA has learned—focus on what varies: pose, clothing, setting, lighting.
5. Assemble Negative Prompt
- Universal Negative (SDXL / SD1.5):
(worst quality:1.4), (low quality:1.4), blurry, deformed, bad anatomy, bad hands, extra fingers, missing fingers, extra limbs, fused fingers, text, watermark, signature, jpeg artifacts, username, error
- Photorealism Negative:
3d render, cartoon, anime, illustration, painting, drawing, cgi, plastic skin, smooth skin, airbrushed, video game, doll, mannequin, oversaturated, artificial lighting
- Video Negative (Wan / AnimateDiff):
static, frozen, jerky motion, low quality, blurry, distorted face, bad anatomy, glitch, artifacts, flickering, jittery, unnatural movement
- FLUX Negative:
blurry, low quality, distorted, deformed, ugly, watermark, text
6. Reference Implementation
The rules above are encoded in a strict TypeScript reference implementation. Use this as the single source of truth for prompt assembly.
export type ModelFamily = "flux" | "sdxl" | "sd15" | "wan" | "animatediff";
export type IdentityMethod = "none" | "instantid" | "pulid" | "ipadapter-faceid" | "flux-kontext" | "character-lora";
export interface CfgRange { readonly min: number; readonly max: number; }
export interface CharacterProfile {
readonly name: string;
readonly triggerWord: string | null;
readonly facialFeatures: readonly string[];
readonly hair: string;
}
export interface PromptRequest {
readonly model: ModelFamily;
readonly identity: IdentityMethod;
readonly : ;
: ;
?: [];
}
{
: ;
: ;
: ;
: [];
}
: <<, >> = {
: { : { : , : }, : [], : , : },
: { : { : , : }, : [, , ], : , : },
: { : { : , : }, : [, ], : , : },
: { : { : , : }, : [], : , : },
: { : { : , : }, : [, ], : , : },
};
: <<, >> = {
: { : , : , : , : },
: { : , : , : { : , : }, : },
: { : , : , : { : , : }, : },
: { : , : , : , : },
: { : , : , : { : , : }, : },
: { : , : , : , : },
};
(): {
}
Pitfalls
- Hardcoding secrets: Never hardcode secrets in prompt scripts or workflow JSON. Workflow files are routinely shared and embedded in PNG metadata. Read credentials from environment variables.
- Untrusted custom nodes: ComfyUI custom nodes are arbitrary Python that runs in your process on load. An untrusted node pack is a remote-code-execution risk. Prefer well-maintained packs.
- Version drift: ComfyUI's node API and conditioning format change between releases. Pin ComfyUI and custom-node versions. Treat a version bump as something to re-validate.
- Over-describing identity: InstantID, PuLID, and IP-Adapter FaceID approximate a face from a reference. Re-describing facial features in text fights the injected conditioning. Expect to iterate on weight and CFG; do not promise pixel-perfect likeness in a single pass.
- Ignoring token limits: SD1.5 has a hard 77-token window. Exceeding it truncates the prompt mechanically.
- Missing motion keywords: For Wan and AnimateDiff, if you only describe appearance, you get a near-static clip. Motion description is the highest-leverage element.
Verification
Confirm the prompt pair before delivering it to the user:
# Quick verification pass
1. Confirm the target checkpoint and identity method
2. Generate one test image with the drafted positive + negative pair
3. Check quality-tag handling matches the model (no "masterpiece" on FLUX)
4. Verify CFG sits in the recommended range for the method stack
5. Confirm identity holds (features not double-specified for InstantID/FaceID)
6. Adjust weights/CFG and re-run only after the single test image passes
Examples
Example 1: FLUX portrait with InstantID
Positive:
photorealistic portrait, wearing a charcoal wool coat, standing on a rainy city
street at night, neon reflections, cinematic side lighting, shallow depth of field,
shot on Sony A7IV, 85mm lens
Negative:
blurry, low quality, distorted, deformed, ugly, watermark, text
CFG: 4–5 (InstantID range)
Example 2: SDXL with a character LoRA
Positive:
masterpiece, best quality, sage_character, photorealistic portrait of a woman,
detailed skin texture with freckles, emerald green eyes, auburn copper hair,
standing on a rooftop at sunset, wind blowing hair, golden hour lighting,
cinematic composition, RAW photo quality, 8k uhd, film grain
Negative:
(worst quality:1.4), (low quality:1.4), blurry, deformed, bad anatomy,
bad hands, extra fingers, missing fingers, extra limbs, fused fingers,
text, watermark, signature, jpeg artifacts, username, error
CFG: 7–9
Example 3: Wan video (talking head)
Positive:
young woman with auburn hair, talking naturally with gentle hand gestures,
seated at a modern desk, soft studio lighting, high quality
Negative:
static, frozen, jerky motion, low quality, blurry, distorted face,
bad anatomy, glitch, artifacts, flickering, jittery, unnatural movement
CFG: 5–7
Related skills
comfyui-character-gen — builds the identity-preserving workflow / node graph that these prompts feed into (InfiniteYou, FLUX Kontext, PuLID, InstantID, IP-Adapter).
