gflow-cli

gflow-cli skill

gflow-cli is an unofficial Python CLI that drives Google Flow — Veo (T2V/I2V) and Imagen / Nano Banana — from the terminal by automating the real Flow web UI in a headed Chrome session (Playwright), not by bypassing it. Source: https://github.com/ffroliva/gflow-cli. Canonical command reference: docs/USAGE.md.

When to invoke this skill

The user wants to:

• Generate one or many Veo videos from text prompts (T2V) or from initial frame + motion prompt (I2V)
• Generate one or many Imagen / Nano Banana images from text (T2I) or from prompt + reference images (I2I)
• Build a batch pipeline for video generations
• Create a reusable, project-scoped Flow Character (a named subject with reference images, optional voice + personality) for consistent subjects across generations (gflow character)
• Compose ordered clips into a scene and optionally render a credit-free server-side extended video (gflow scene)
• Stitch a multi-clip story where each clip is seeded by the previous clip's last frame (gflow video chain)
• Use their Flow credits via script instead of clicking through the UI
• Automate Flow inside a content pipeline, AI video production stack, or research project

Do NOT use this skill when:

• The user wants production-grade reliability with SLAs — recommend the official Gen AI SDK instead.
• The user asks about audio, music, or anything outside Flow's video/image surface — wrong tool.

Prerequisites

Before any gflow-cli invocation, verify:

1. Python 3.11+ is available (python --version).
2. uv is installed (uv --version). If not, install: curl -LsSf https://astral.sh/uv/install.sh | sh (or Windows equivalent from https://docs.astral.sh/uv/).
3. gflow-cli is installed OR available via uvx:
   • Quick: uvx --from gflow-cli gflow --help (no install)
   • Persistent: uv tool install gflow-cli && gflow --help
4. Playwright Chromium has been downloaded once: uvx --from gflow-cli playwright install chromium (~150 MB).
5. A signed-in profile exists: gflow auth status should print Flow session verified and exit 0 (it probes the live Flow session endpoint — no browser, no credits; exit 1 means dead or missing session). If not, run gflow auth login and walk the user through the one-time browser sign-in.
6. The user has Flow access — any Google account with Flow rolled out works. If gflow image upload returns 403, missing Flow access is the cause.

Core commands

# Auth (one-time)
gflow auth login                                          # opens Chromium, user signs in
gflow auth status                                         # confirms session
gflow auth                                                # bare: list profiles or trigger first login
gflow auth logout                                         # delete a saved session

# Image generation (Imagen / Nano Banana)
gflow image upload <path>                                 # → asset UUID + dimensions
gflow image t2i "<prompt>" [--model {nano2|nano-pro|image4}] \
                            [--aspect {9:16|16:9|1:1|4:3|3:4}] \
                            [-n 1..4] [--out DIR]
gflow image i2i "<prompt>" --ref PATH_OR_UUID [--ref ...] [...same as t2i]
gflow image batch <manifest.tsv|manifest.json> [-n 1..4] [--aspect ...] [--out DIR]  # shared project, up to 5 prompts

# Video generation (Veo 3.1)
gflow video t2v "<prompt>" [--out-dir DIR] [--aspect ...]
gflow video i2v --initial-frame <image|media-UUID> "<prompt>" [--out-dir DIR] [...same as t2v]  # UUID = in-project asset, no re-upload (#287; pair with --project)
# `gflow video` has no `batch` subcommand — that stub never worked and was
# removed. For multi-clip runs, loop `gflow video t2v`/`i2v` from the shell.
gflow video chain <manifest.jsonl> [--out-dir DIR] [--dry-run] \
                  [--max-links N] [--resume-from N]   # last-frame I2V chaining; veo models only

# Characters (reusable, project-scoped subjects)
gflow character create --project <id> --name "<name>" --face-prompt "<prompt>" \
                       [--body-prompt "<prompt>"] [--voice <id>] [--personality "<text>"] \
                       [--model {nano2|nanopro}]
gflow character list --project <id>
gflow character show <character-id> --project <id>
gflow character rm --project <id> (--id <character-id> | --name "<name>") [--yes]   # delete (FREE)
gflow character voices                                    # list the Gemini voice catalog

# Scenes (Add Clip / compose ordered clips)
gflow scene create --project <id> <clip-id> [<clip-id> ...] \
                   [-o extended.mp4]                       # --output = credit-free server-side concat
gflow scene show <scene-id> --project <id>

# Agent instructions (project brief cards, credits-free setup) — --project is REQUIRED
gflow instructions add TITLE --text TEXT [--ref REF]... --project ID [--disabled]
gflow instructions list --project ID [--json]
gflow instructions enable (TITLE | --id ID) --project ID
gflow instructions disable (TITLE | --id ID) --project ID
gflow instructions rm (TITLE | --id ID) --project ID
gflow instructions apply FILE --project ID                # declarative full-sync (TOML/JSON)
gflow instructions toggle-mode (--on | --off) --project ID # toggle master agent switch

Every subcommand accepts --profile <name> (per-subcommand, not global) to drive multiple Google accounts side-by-side.

Recipes

Single image (most common)

gflow image t2i "a hot air balloon over Tokyo at sunrise" --aspect 16:9

Image fan-out (4 variants in parallel)

gflow image t2i "variations of a minimalist fox logo" -n 4 --aspect 1:1 --out ./logos/

Image-to-image with a local reference

gflow image i2i "make it cinematic, golden hour" --ref hero.png

Image-to-image with an already-uploaded asset UUID (no re-upload)

UUID=$(gflow image upload hero.png | awk '/Asset UUID:/ {print $3}')
gflow image i2i "stylize this asset" --ref "$UUID"

Single clip from initial frame

gflow video i2v --initial-frame ./input.png "Slow cinematic push-in, soft golden light at sunset" --out-dir outputs

Batch from a directory of inputs (bash)

There is no manifest-driven video batch command — that stub never worked and was removed. Loop gflow video t2v/i2v from the shell instead:

mkdir -p out
for img in ./inputs/*.png; do
  name=$(basename "$img" .png)
  gflow video i2v --initial-frame "$img" "Cinematic push-in" --out-dir out
done

New-Item -ItemType Directory -Force -Path out | Out-Null
Get-ChildItem ./inputs/*.png | ForEach-Object {
    gflow video i2v --initial-frame $_.FullName "Cinematic push-in" --out-dir out
}

Create a reusable Character for consistent subjects

# A Character is a named, project-scoped subject reused across generations.
gflow character create --project "$PROJECT_ID" --name "Joaquim" \
  --face-prompt "weathered fisherman, grey beard, kind eyes" \
  --body-prompt "tall, broad-shouldered, wearing a navy wool sweater" \
  --voice <voice-id> --model nano2
gflow character voices            # discover valid --voice ids first
gflow character list --project "$PROJECT_ID"

See docs/CHARACTER.md for the full domain model, wire protocol, and the crash-recoverable persist-before-spend saga.

Compose clips into an extended video (credit-free)

# Concatenate ordered clips server-side via runVideoFxConcatenation — no local ffmpeg, no credits.
gflow scene create --project "$PROJECT_ID" "$CLIP_A" "$CLIP_B" -o extended.mp4

Chain clips by last frame (story stitching)

# manifest.jsonl: one JSON object per line. Link 0 = t2v; later links = i2v seeded by the
# previous clip's last frame. Each link is a pending video operation; credit
# use varies by model/duration/tier — check Flow. veo models only.
gflow video chain ./story.jsonl --out-dir ./out/ --dry-run   # preview the plan first
gflow video chain ./story.jsonl --out-dir ./out/             # then run for real

Sync instructions and generate (3-layer pipeline)

# 1. Discover project ID from Flow editor URL (.../project/<id>/...) or create one.
# 2. Set up the brief cards (credits-free setup).
gflow instructions apply brief.toml --project 6b714c4e-...
# 3. Generate using that project context (steers via reasoning path).
gflow image t2i "a bicycle" --project 6b714c4e-...

Use as a Python library

import asyncio
from pathlib import Path
from gflow_cli.api.client import FlowApiClient
from gflow_cli.paths import profile_dir

async def make_clip(image: Path, prompt: str, out: Path) -> None:
    async with FlowApiClient(profile_dir=profile_dir("default")) as client:
        project = await client.create_project(title="gflow-cli demo")
        asset = await client.upload_image(image, project.project_id)
        op = await client.generate_video(
            project_id=project.project_id,
            prompt=prompt,
            start_asset=asset,
            aspect="9:16",
        )
        # Poll op.workflow_id with client.poll_video_status(...) and
        # client.download_video(...) when status reaches succeeded.

asyncio.run(make_clip(Path("in.png"), "Push-in", Path("out.mp4")))

Layered Instructions Pipeline

The gflow-cli supports a 3-layer pipeline for persistent generation context (Agent Mode brief cards):

1. Layer 1 (Setup - credits-free): Set up the project brief cards using gflow instructions add or gflow instructions apply.
2. Layer 2 (Generate): Run generations targeting that project with --project <id>. Enabled brief cards are automatically resolved and folded into the prompt via the agent's reasoning path.
3. Layer 3 (Compose): Scene-level composition overrides via movie.toml [[scene.instructions.card]] or [scene.instructions] disable blocks.

Constraints & Rules:

• Discover Project ID First: Persistent cards require a real project. Discover the project ID from the Flow browser editor URL (.../project/<id>/...) or create one.
• DO NOT use the ephemeral -i / --instruction option for anything you want to reuse; it creates a new card every call. Prefer persistent gflow instructions cards.
• Master Switch: Ensure agent mode is toggled on (gflow instructions toggle-mode --on) for cards to steer output.

Common errors and fixes

Important constraints

• Costs real money / credits. Each gflow video t2v|i2v and gflow image t2i|i2i call burns Flow credits from the user's Google account. Confirm before running batches.
• Not for production-grade SLAs. gflow-cli reverse-engineers a private Google API. It can break without notice. For production, use the official Gen AI SDK.
• Don't share auth profiles. The Playwright profile dir lives at the per-OS user-data location (Windows: %LOCALAPPDATA%\gflow-cli\profile_*; macOS: ~/Library/Application Support/gflow-cli/profile_*; Linux: ~/.local/share/gflow-cli/profile_*) and contains Google session cookies — treat as secrets.
• Same profile can't run in parallel. Chromium refuses two persistent contexts on the same profile dir; use different --profile names for parallel work.
• Respect Google's Generative AI Prohibited Use Policy. Don't generate content that would get the user's Google account banned.

Known agent failure modes

Documented errors agents commonly make — negative examples for the SkillOpt training loop:

Disclaimer

gflow-cli is not affiliated with Google. Reverse-engineered, unofficial; may break when Google changes Flow's private API. Read the DISCLAIMER before deploying in any sensitive setting.