James RussoandClaude Fable 5 0766eb8144 feat(cli): detect Gemini managed-agent sandbox in detectAgentRuntime (#1294)
* feat(cli): detect Gemini managed-agent sandbox in detectAgentRuntime

Add `gemini_managed_agent` to the AgentRuntime union and a dedicated
isGeminiManagedAgent() detector. Empirical signal pair (from live-sandbox
introspection by gemini-agent, env_id b9db4e56, 2026-06-09):

  existsSync('/.agents/AGENTS.md')  AND  isGVisor()

The conjunction is what makes the rule safe:

  - `/.agents/AGENTS.md` excludes generic gVisor surfaces (GKE Sandbox,
    Cloud Run gen2) that don't mount the managed-agent layout.
  - The gVisor kernel check excludes a dev box that happens to have a
    stray `/.agents/` directory.

Implementation notes:

  - Filesystem-based check runs ahead of the env-var-only VENDOR_RULES
    loop. VENDOR_RULES is documented as "Only checks for the EXISTENCE
    of well-known env vars — never reads their values"; the Gemini
    signal is filesystem + kernel, not env, so it gets a dedicated
    branch rather than shoehorning into the rule list.

  - GEMINI_API_KEY is deliberately NOT keyed on — it's user-settable on
    any host. The filesystem + kernel pair is the actually-distinctive
    signal.

  - Reuses the existing isGVisor() helper for the kernel half of the
    conjunction; no duplication.

Tests (4 new, vitest):

  - Positive: /.agents/AGENTS.md + 4.19.0-gvisor → gemini_managed_agent
  - Negative: gVisor alone (no /.agents/) → null (generic gVisor surface)
  - Negative: /.agents/AGENTS.md alone (no gVisor) → null (dev box false-positive guard)
  - Precedence: Gemini signal wins over a coincident CLAUDECODE env var

Empirical caveat: signal was gathered from a single sandbox. Re-confirming
across additional sandbox spins is a follow-up; the rule is conservative
enough (conjunction of two independent signals) that a single-spin
false-positive is unlikely, but a single-spin variance bug (e.g. some
sandbox flavors omitting one of the two markers) would surface as
under-detection rather than over-detection.

Source for signals: introspection write-up at
/tmp/gemini-sandbox-detection-signals.md (gemini-agent, 2026-06-09).

* docs(cli): reframe Gemini-managed-agent detection rationale (load-bearing vs guard)

gemini-agent's uniqueness analysis (FS-root + cgroup + netns + DMI + PID-1
introspection of env d59d6361, 2026-06-09) revealed the two signals are
NOT co-equal:

- /.agents/AGENTS.md is the uniqueness anchor — definitionally a
  managed-agent artifact, injected per-run by the platform, mtime
  tracks the interaction. Nothing in the generic Google-Cloud-on-gVisor
  universe (Cloud Run gen2, GKE Sandbox, Fly.io) mounts /.agents/.
- isGVisor() is a guard, not a second uniqueness signal. gVisor itself
  is shared with GKE Sandbox + Cloud Run gen2 — its real job here is
  ruling out a stray user-created /.agents/AGENTS.md on a non-sandbox
  host.

The original 3-spin work proved *stability* (signals consistent across
sandbox spins). This pass adds *uniqueness* — confirming the signals
discriminate Antigravity from the broader gVisor universe, not just
that they're reliably present. Stability ≠ uniqueness; both are
required for a correct detection rule.

Code unchanged (the AND-gate is sound). Docstring reframed so a future
reader doesn't mistake the conjunction for two independent uniqueness
signals. Also enumerated the markers NOT keyed on (with reasons), so
future contributors don't reach for them by naming inference.

Source: gemini-agent uniqueness analysis write-up.

* fix(cli): key Gemini managed-agent detection on /.agents/ mount, not optional AGENTS.md

The detector keyed on existsSync('/.agents/AGENTS.md'), but Google's Managed
Agents docs are explicit that AGENTS.md is OPTIONAL: an agent may declare its
instructions inline via system_instruction in agent.yaml and ship no AGENTS.md
file ("system_instruction and AGENTS.md are additive; both apply when present").
The platform auto-discovers the agent under the /.agents/ directory; skills
mount at /.agents/skills/ and AGENTS.md at /.agents/AGENTS.md only when shipped.

Keying on the file generalized only to templates that happen to bundle an
AGENTS.md (like HeyGen's own gemini-agent and Thor's reference). A managed agent
defined with inline instructions or a skills-only definition was a silent
false-negative. All three prior verification spins used our own AGENTS.md-bearing
template, so the gap was never exercised.

Broaden to the /.agents/ directory mount (still gVisor-guarded — false-positive
surface is unchanged) so skills-only and inline-instruction agents are detected.
Adds a regression test for the skills-but-no-AGENTS.md case. Documents the one
residual gap (pure inline-only, no skills/no AGENTS.md) that needs an empirical
spin to confirm.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* refactor(cli): tighten /.agents/ to a directory check + sync agent_runtime docs

Self-review follow-ups (no behavior change for real managed agents):

- isGeminiManagedAgent now requires statSync("/.agents").isDirectory() rather
  than existsSync("/.agents"), matching the documented "directory mount"
  contract. existsSync matched any entry (a stray file/symlink named /.agents),
  widening the gVisor-gated false-positive surface beyond what the comment
  claimed. Tests now mock statSync accordingly (and drop a dead /.agents/skills
  mock clause the code never read).
- system.ts: the agent_runtime doc comment hard-coded the vendor list and said
  "detected by env-var existence only" — both stale once a filesystem/kernel
  detector (gemini_managed_agent) exists. Point at the AgentRuntime union and
  note the filesystem-marker case instead.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

---------

Co-authored-by: Claude Fable 5 <noreply@anthropic.com>
2026-06-10 17:05:50 -07:00
2026-06-10 23:26:13 +00:00
2026-06-10 23:26:13 +00:00
2026-06-10 23:26:13 +00:00
2026-06-10 23:26:13 +00:00
2026-06-10 23:26:13 +00:00
2026-03-21 22:43:56 -07:00

HyperFrames

npm version npm downloads License Node.js Discord

Write HTML. Render video. Built for agents.

Quickstart | Showcase | Playground | Catalog | Docs | Discord

HyperFrames demo: HTML code on the left transforms into a rendered video on the right

HyperFrames is an open-source framework for turning HTML, CSS, media, and seekable animations into deterministic MP4 videos. Use it locally with the CLI, from AI coding agents with skills, or as the rendering core behind hosted authoring workflows.

Quick Start

With an AI coding agent

Install the HyperFrames skills, then describe the video you want:

npx skills add heygen-com/hyperframes

Try a prompt like:

Using /hyperframes, create a 10-second product intro with a fade-in title, a background video, and subtle background music.

The skills teach agents the HyperFrames production loop: plan the video, write valid HTML, wire seekable animations, add media, lint, preview, and render. They work with Claude Code, Cursor, Gemini CLI, Codex, and other coding agents that support skills.

For visual design handoff workflows, see the Claude Design guide and Open Design guide.

Manually with the CLI

npx hyperframes init my-video
cd my-video
npx hyperframes preview      # preview in browser with live reload
npx hyperframes render       # render to MP4

Requirements: Node.js 22+, FFmpeg

What You Can Build

Need ideas? Browse the Showcase for finished videos you can watch, read, run, and remix.

  • Product launch videos and feature announcements
  • PR walkthroughs with animated code diffs, narration, and captions
  • Data visualizations, chart races, and map animations
  • Social videos with kinetic captions, overlays, and music
  • Docs-to-video, PDF-to-video, and website-to-video explainers
  • Reusable motion graphics for automated content pipelines

Frame.md

frame.md — your design system, ready for video.

Every brand has a design.md. None of them were written for a camera. frame.md is the missing translation layer: it takes your web-context design spec and inverts it for the frame — the same tokens, the same rules, but rewritten so an AI agent can compose a promo video without guessing at scale or reaching for web chrome.

The output is a DESIGN.md superset your whole toolchain can read. Atoms stay sacred. Composition stays free. Numbers come from the script.

Biennale Yellow
Biennale Yellow
BlockFrame
BlockFrame
Blue Professional
Blue Professional
Bold Poster
Bold Poster
Broadside
Broadside
Capsule
Capsule
Cartesian
Cartesian
Cobalt Grid
Cobalt Grid
Coral
Coral
Creative Mode
Creative Mode

Browse and remix them all at hyperframes.dev/design.

How It Works

Define a video as HTML. Add data attributes for timing and tracks. Use GSAP, CSS, Lottie, Three.js, Anime.js, WAAPI, or your own frame adapter for seekable animation.

<div id="stage" data-composition-id="launch" data-start="0" data-width="1920" data-height="1080">
  <video
    class="clip"
    data-start="0"
    data-duration="6"
    data-track-index="0"
    src="intro.mp4"
    muted
    playsinline
  ></video>

  <h1 id="title" class="clip" data-start="1" data-duration="4" data-track-index="1">Launch day</h1>

  <audio
    data-start="0"
    data-duration="6"
    data-track-index="2"
    data-volume="0.5"
    src="music.wav"
  ></audio>

  <script src="https://cdn.jsdelivr.net/npm/gsap@3/dist/gsap.min.js"></script>
  <script>
    const tl = gsap.timeline({ paused: true });
    tl.from("#title", { opacity: 0, y: 40, duration: 0.8 }, 1);
    window.__timelines = window.__timelines || {};
    window.__timelines.launch = tl;
  </script>
</div>

Preview instantly in the browser. Render locally or in Docker. The renderer seeks each frame in headless Chrome and encodes the result with FFmpeg, so the same input produces the same video.

HyperFrames Stack

HyperFrames is the open-source rendering engine, plus a growing set of tools around HTML-native video creation.

Piece Status What it does
CLI Available Scaffold, preview, lint, inspect, and render local video projects
Core / Engine / Producer Available Parse compositions, drive headless Chrome, encode video, and mix audio
Catalog Available Reusable blocks and components for transitions, overlays, captions, charts, maps, and effects
Agent skills Available Teach coding agents the video-production patterns that generic web docs miss
Studio Available, evolving Browser surface for previewing and editing compositions
AWS Lambda rendering Available Deploy a distributed render stack and drive renders from your laptop or CI
hyperframes.dev Available Community playground for previewing, iterating, sharing, and rendering HTML-native video projects
frame.md Available Invert your design system for the camera — a DESIGN.md superset an agent can compose video from

Catalog

Install ready-to-use blocks and components:

npx hyperframes add flash-through-white   # shader transition
npx hyperframes add instagram-follow      # social overlay
npx hyperframes add data-chart            # animated chart

Browse the catalog at hyperframes.heygen.com/catalog.

Why HyperFrames?

  • HTML-native: compositions are HTML files with data attributes. No React requirement, no proprietary timeline format.
  • Agent-friendly: agents already write HTML, and the CLI is non-interactive by default.
  • Deterministic: same input, same frames, same output. Built for CI, regression tests, and automated rendering.
  • No build step: an index.html composition plays as-is and can be previewed directly in the browser.
  • Adapter-based animation: bring GSAP, CSS animations, Lottie, Three.js, Anime.js, WAAPI, or a custom runtime.
  • Open source: Apache 2.0 license, with no per-render fees or commercial-use thresholds.

HyperFrames vs Remotion

HyperFrames is inspired by Remotion. Both tools render video with headless Chrome and FFmpeg. The main difference is the authoring model: Remotion's bet is React components; HyperFrames' bet is plain HTML that humans and agents can both write easily.

HyperFrames Remotion
Authoring HTML + CSS + seekable animation React components
Build step None; index.html plays as-is Bundler required
Agent handoff Plain HTML files JSX / React project
Library-clock animations Seekable, frame-accurate via adapters Wall-clock animation patterns need care
Distributed rendering Local and AWS Lambda render paths Remotion Lambda, mature cloud renderer
License Apache 2.0 Source-available Remotion License

Read the full comparison in the HyperFrames vs Remotion guide.

Documentation

Full documentation: hyperframes.heygen.com/introduction

Packages

Package Description
hyperframes CLI for creating, previewing, linting, and rendering compositions
@hyperframes/core Types, parsers, generators, linter, runtime, and frame adapters
@hyperframes/engine Seekable page-to-video capture engine using Puppeteer and FFmpeg
@hyperframes/producer Full rendering pipeline for capture, encode, and audio mix
@hyperframes/studio Browser-based composition editor UI
@hyperframes/player Embeddable <hyperframes-player> web component
@hyperframes/shader-transitions WebGL shader transitions for compositions
@hyperframes/aws-lambda AWS Lambda SDK and deployment surface for distributed renders

Community

HyperFrames is used in production at HeyGen, with community examples from teams like tldraw, TanStack, and others in ADOPTERS.md. Open a PR if your team is using HyperFrames.

Development Note

The repo uses Git LFS for golden regression-test baselines under packages/producer/tests/**/output.mp4 (about 240 MB of .mp4 files). If you're cloning the full repo for development, install Git LFS first:

# macOS
brew install git-lfs

# Ubuntu / Debian
sudo apt install git-lfs

# Windows
winget install GitHub.GitLFS

# Then, once per machine
git lfs install

If you only need source files, you can skip LFS content:

GIT_LFS_SKIP_SMUDGE=1 git clone https://github.com/heygen-com/hyperframes.git

License

Apache 2.0

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Write HTML. Render video. Built for agents.
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