hermes-agent/website/docs/user-guide/features/image-generation.md
Teknium 01906e99dd
feat(image_gen): multi-model FAL support with picker in hermes tools (#11265)
* feat(image_gen): multi-model FAL support with picker in hermes tools

Adds 8 FAL text-to-image models selectable via `hermes tools` →
Image Generation → (FAL.ai | Nous Subscription) → model picker.

Models supported:
- fal-ai/flux-2/klein/9b (new default, <1s, $0.006/MP)
- fal-ai/flux-2-pro (previous default, kept backward-compat upscaling)
- fal-ai/z-image/turbo (Tongyi-MAI, bilingual EN/CN)
- fal-ai/nano-banana (Gemini 2.5 Flash Image)
- fal-ai/gpt-image-1.5 (with quality tier: low/medium/high)
- fal-ai/ideogram/v3 (best typography)
- fal-ai/recraft-v3 (vector, brand styles)
- fal-ai/qwen-image (LLM-based)

Architecture:
- FAL_MODELS catalog declares per-model size family, defaults, supports
  whitelist, and upscale flag. Three size families handled uniformly:
  image_size_preset (flux family), aspect_ratio (nano-banana), and
  gpt_literal (gpt-image-1.5).
- _build_fal_payload() translates unified inputs (prompt + aspect_ratio)
  into model-specific payloads, merges defaults, applies caller overrides,
  wires GPT quality_setting, then filters to the supports whitelist — so
  models never receive rejected keys.
- IMAGEGEN_BACKENDS registry in tools_config prepares for future imagegen
  providers (Replicate, Stability, etc.); each provider entry tags itself
  with imagegen_backend: 'fal' to select the right catalog.
- Upscaler (Clarity) defaults off for new models (preserves <1s value
  prop), on for flux-2-pro (backward-compat). Per-model via FAL_MODELS.

Config:
  image_gen.model           = fal-ai/flux-2/klein/9b  (new)
  image_gen.quality_setting = medium                  (new, GPT only)
  image_gen.use_gateway     = bool                    (existing)

Agent-facing schema unchanged (prompt + aspect_ratio only) — model
choice is a user-level config decision, not an agent-level arg.

Picker uses curses_radiolist (arrow keys, auto numbered-fallback on
non-TTY). Column-aligned: Model / Speed / Strengths / Price.

Docs: image-generation.md rewritten with the model table and picker
walkthrough. tools-reference, tool-gateway, overview updated to drop
the stale "FLUX 2 Pro" wording.

Tests: 42 new in tests/tools/test_image_generation.py covering catalog
integrity, all 3 size families, supports filter, default merging, GPT
quality wiring, model resolution fallback. 8 new in
tests/hermes_cli/test_tools_config.py for picker wiring (registry,
config writes, GPT quality follow-up prompt, corrupt-config repair).

* feat(image_gen): translate managed-gateway 4xx to actionable error

When the Nous Subscription managed FAL proxy rejects a model with 4xx
(likely portal-side allowlist miss or billing gate), surface a clear
message explaining:
  1. The rejected model ID + HTTP status
  2. Two remediation paths: set FAL_KEY for direct access, or
     pick a different model via `hermes tools`

5xx, connection errors, and direct-FAL errors pass through unchanged
(those have different root causes and reasonable native messages).

Motivation: new FAL models added to this release (flux-2-klein-9b,
z-image-turbo, nano-banana, gpt-image-1.5, ideogram-v3, recraft-v3,
qwen-image) are untested against the Nous Portal proxy. If the portal
allowlists model IDs, users on Nous Subscription will hit cryptic
4xx errors without guidance on how to work around it.

Tests: 8 new cases covering status extraction across httpx/fal error
shapes and 4xx-vs-5xx-vs-ConnectionError translation policy.

Docs: brief note in image-generation.md for Nous subscribers.

Operator action (Nous Portal side): verify that fal-queue-gateway
passes through these 7 new FAL model IDs. If the proxy has an
allowlist, add them; otherwise Nous Subscription users will see the
new translated error and fall back to direct FAL.

* feat(image_gen): pin GPT-Image quality to medium (no user choice)

Previously the tools picker asked a follow-up question for GPT-Image
quality tier (low / medium / high) and persisted the answer to
`image_gen.quality_setting`. This created two problems:

1. Nous Portal billing complexity — the 22x cost spread between tiers
   ($0.009 low / $0.20 high) forces the gateway to meter per-tier per
   user, which the portal team can't easily support at launch.
2. User footgun — anyone picking `high` by mistake burns through
   credit ~6x faster than `medium`.

This commit pins quality at medium by baking it into FAL_MODELS
defaults for gpt-image-1.5 and removes all user-facing override paths:

- Removed `_resolve_gpt_quality()` runtime lookup
- Removed `honors_quality_setting` flag on the model entry
- Removed `_configure_gpt_quality_setting()` picker helper
- Removed `_GPT_QUALITY_CHOICES` constant
- Removed the follow-up prompt call in `_configure_imagegen_model()`
- Even if a user manually edits `image_gen.quality_setting` in
  config.yaml, no code path reads it — always sends medium.

Tests:
- Replaced TestGptQualitySetting (6 tests) with TestGptQualityPinnedToMedium
  (5 tests) — proves medium is baked in, config is ignored, flag is
  removed, helper is removed, non-gpt models never get quality.
- Replaced test_picker_with_gpt_image_also_prompts_quality with
  test_picker_with_gpt_image_does_not_prompt_quality — proves only 1
  picker call fires when gpt-image is selected (no quality follow-up).

Docs updated: image-generation.md replaces the quality-tier table
with a short note explaining the pinning decision.

* docs(image_gen): drop stale 'wires GPT quality tier' line from internals section

Caught in a cleanup sweep after pinning quality to medium. The
"How It Works Internally" walkthrough still described the removed
quality-wiring step.
2026-04-16 20:19:53 -07:00

6.3 KiB
Raw Blame History

title description sidebar_label sidebar_position
Image Generation Generate images via FAL.ai — 8 models including FLUX 2, GPT-Image, Nano Banana, Ideogram, and more, selectable via `hermes tools`. Image Generation 6

Image Generation

Hermes Agent generates images from text prompts via FAL.ai. Eight models are supported out of the box, each with different speed, quality, and cost tradeoffs. The active model is user-configurable via hermes tools and persists in config.yaml.

Supported Models

Model Speed Strengths Price
fal-ai/flux-2/klein/9b (default) <1s Fast, crisp text $0.006/MP
fal-ai/flux-2-pro ~6s Studio photorealism $0.03/MP
fal-ai/z-image/turbo ~2s Bilingual EN/CN, 6B params $0.005/MP
fal-ai/nano-banana ~6s Gemini 2.5, character consistency $0.08/image
fal-ai/gpt-image-1.5 ~15s Prompt adherence $0.034/image
fal-ai/ideogram/v3 ~5s Best typography $0.030.09/image
fal-ai/recraft-v3 ~8s Vector art, brand styles $0.04/image
fal-ai/qwen-image ~12s LLM-based, complex text $0.02/MP

Prices are FAL's pricing at time of writing; check fal.ai for current numbers.

Setup

:::tip Nous Subscribers If you have a paid Nous Portal subscription, you can use image generation through the Tool Gateway without a FAL API key. Your model selection persists across both paths.

If the managed gateway returns HTTP 4xx for a specific model, that model isn't yet proxied on the portal side — the agent will tell you so, with remediation steps (set FAL_KEY for direct access, or pick a different model). :::

Get a FAL API Key

  1. Sign up at fal.ai
  2. Generate an API key from your dashboard

Configure and Pick a Model

Run the tools command:

hermes tools

Navigate to 🎨 Image Generation, pick your backend (Nous Subscription or FAL.ai), then the picker shows all supported models in a column-aligned table — arrow keys to navigate, Enter to select:

  Model                          Speed    Strengths                    Price
  fal-ai/flux-2/klein/9b         <1s      Fast, crisp text             $0.006/MP   ← currently in use
  fal-ai/flux-2-pro              ~6s      Studio photorealism          $0.03/MP
  fal-ai/z-image/turbo           ~2s      Bilingual EN/CN, 6B          $0.005/MP
  ...

Your selection is saved to config.yaml:

image_gen:
  model: fal-ai/flux-2/klein/9b
  use_gateway: false            # true if using Nous Subscription

GPT-Image Quality

The fal-ai/gpt-image-1.5 request quality is pinned to medium (~$0.034/image at 1024×1024). We don't expose the low / high tiers as a user-facing option so that Nous Portal billing stays predictable across all users — the cost spread between tiers is ~22×. If you want a cheaper GPT-Image option, pick a different model; if you want higher quality, use Klein 9B or Imagen-class models.

Usage

The agent-facing schema is intentionally minimal — the model picks up whatever you've configured:

Generate an image of a serene mountain landscape with cherry blossoms
Create a square portrait of a wise old owl — use the typography model
Make me a futuristic cityscape, landscape orientation

Aspect Ratios

Every model accepts the same three aspect ratios from the agent's perspective. Internally, each model's native size spec is filled in automatically:

Agent input image_size (flux/z-image/qwen/recraft/ideogram) aspect_ratio (nano-banana) image_size (gpt-image)
landscape landscape_16_9 16:9 1536x1024
square square_hd 1:1 1024x1024
portrait portrait_16_9 9:16 1024x1536

This translation happens in _build_fal_payload() — agent code never has to know about per-model schema differences.

Automatic Upscaling

Upscaling via FAL's Clarity Upscaler is gated per-model:

Model Upscale? Why
fal-ai/flux-2-pro Backward-compat (was the pre-picker default)
All others Fast models would lose their sub-second value prop; hi-res models don't need it

When upscaling runs, it uses these settings:

Setting Value
Upscale factor 2×
Creativity 0.35
Resemblance 0.6
Guidance scale 4
Inference steps 18

If upscaling fails (network issue, rate limit), the original image is returned automatically.

How It Works Internally

  1. Model resolution_resolve_fal_model() reads image_gen.model from config.yaml, falls back to the FAL_IMAGE_MODEL env var, then to fal-ai/flux-2/klein/9b.
  2. Payload building_build_fal_payload() translates your aspect_ratio into the model's native format (preset enum, aspect-ratio enum, or GPT literal), merges the model's default params, applies any caller overrides, then filters to the model's supports whitelist so unsupported keys are never sent.
  3. Submission_submit_fal_request() routes via direct FAL credentials or the managed Nous gateway.
  4. Upscaling — runs only if the model's metadata has upscale: True.
  5. Delivery — final image URL returned to the agent, which emits a MEDIA:<url> tag that platform adapters convert to native media.

Debugging

Enable debug logging:

export IMAGE_TOOLS_DEBUG=true

Debug logs go to ./logs/image_tools_debug_<session_id>.json with per-call details (model, parameters, timing, errors).

Platform Delivery

Platform Delivery
CLI Image URL printed as markdown ![](url) — click to open
Telegram Photo message with the prompt as caption
Discord Embedded in a message
Slack URL unfurled by Slack
WhatsApp Media message
Others URL in plain text

Limitations

  • Requires FAL credentials (direct FAL_KEY or Nous Subscription)
  • Text-to-image only — no inpainting, img2img, or editing via this tool
  • Temporary URLs — FAL returns hosted URLs that expire after hours/days; save locally if needed
  • Per-model constraints — some models don't support seed, num_inference_steps, etc. The supports filter silently drops unsupported params; this is expected behavior