HyperFrames is an open-source framework that turns HTML, CSS, media, and timed animations into deterministic MP4 videos. It is used locally, by coding agents, and in hosted authoring workflows to create rendered videos from web-based designs. Its catalogue add-ons provide skills, agents, instructions, hooks, settings, and a plugin for agent-driven video production.
Borrowing it
Nothing to install: this file belongs to heygen-com/hyperframes. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/heygen-com/hyperframes/main/.agents/skills/captions-overlay/SKILL.mdgit clone --depth 1 https://github.com/heygen-com/hyperframesWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/heygen-com/hyperframes/captions-overlay)<a href="https://agentmods.dev/skills/heygen-com/hyperframes/captions-overlay"><img src="https://agentmods.dev/badge/skills/heygen-com/hyperframes/captions-overlay/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/heygen-com/hyperframes/captions-overlay"><img src="https://agentmods.dev/badge/skills/heygen-com/hyperframes/captions-overlay.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- Socket pass
- Snyk pass
- NVIDIA SkillSpector warn
SkillSpector: 2 findings, up to medium
These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →
- medium Prompt Injection · line 22 Large whitespace padding was detected (a block of blank lines or a long run of spaces). This can push injected instructions below or to the right of the visible area so a human reviewer never sees them while the agent still reads them. Manual review of the hidden content is recommended.Fix: Remove the large whitespace padding (blank-line blocks or long space runs) and review any content hidden below or to the right of it. Keep skill files compact and reviewable so no instructions can be
- medium Prompt Injection · line 24 Large whitespace padding was detected (a block of blank lines or a long run of spaces). This can push injected instructions below or to the right of the visible area so a human reviewer never sees them while the agent still reads them. Manual review of the hidden content is recommended.Fix: Remove the large whitespace padding (blank-line blocks or long space runs) and review any content hidden below or to the right of it. Keep skill files compact and reviewable so no instructions can be
What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00139 | $0.01205 |
| Opus 5.5 | $0.00056 | $0.00482 |
| Sonnet 5.5 | $0.00028 | $0.00241 |
| Haiku 4.5 | $0.00014 | $0.00120 |
Grade A, and why
captions-overlay scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 17d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
Copies of this mod
1 near-identical copy found in the catalogue:
- captions-overlay — 100% identical, 35 lines differ
How it starts
The opening of the file, as written. The whole thing — 81 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Captions Overlay Doctrine
Overlay doctrine — supplements the upstream
/hyperframesskill'sreferences/captions.md. Applies ON TOP of it; do not expect it folded into the upstream skill.
Two ideas combine here. First, the caption model — every spoken phrase is drop,
rail, or embed, and embed is the scarce earned peak, not the default. Second, the
overlay law — a caption line is composited ON TOP of the film as an overlay; it is
NOT a reserved zone, so you never shift content up or leave a dead band to "make room"
for it. The two reinforce each other: because captions ride as an overlay (the verbatim
rail in front, the occasional embed behind the subject), the composition keeps its full
frame and centers on the true vertical center.
The caption model — drop / rail / embed
Every spoken phrase is one of three things:
| What | How it's shown | |
|---|---|---|
| drop | filler — um/uh, stutters, self-corrections | not shown |
| rail | the default — ordinary spoken content (verbatim) | clean lower-third subtitle, in front, readable. A punch word can get an inline emphasis highlight (accent colour / active-word pop) — it stays on the rail. |
| embed | a promoted peak — the headline beat | one big word composited behind the subject (matte occlusion), designed entrance + exit |
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 17d ago Changed · -3 lines · +3 tokens per session 95edff863c75
- 1mo ago Changed · +2 lines dde58d4fcad6
- 2mo ago First seen · 82 lines · 136 tokens per session scan A 84cf9826a978
captions-overlay is a skill published in the GitHub repository heygen-com/hyperframes (80,260 stars, last pushed today), licensed Apache-2.0. It adds 139 tokens to every session and 1,205 once invoked, about $0.0006 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
captions-overlay compared with skills from other repositories
| Mod | Type | Stars | Last push | Licence | Scan | Tokens | Works with |
|---|---|---|---|---|---|---|---|
| captions-overlayheygen-com/hyperframes | Skill | 80k | today | Apache-2.0 | A | 139 | Claude Code |
| html-to-videowx4766/html-to-video | Skill | 185 | yesterday | MIT | A | 267 | Claude Code, Codex |
| architecture-diagramAgentEra/Agently | Skill | 1.7k | 25d ago | Apache-2.0 | A | 47 | Claude Code, Codex |
| motion2codelovisdotio/motion2code | Skill | 338 | 18d ago | MIT | A | 187 | Claude Code, Codex |
| remotionoyi77/1ai-skills | Skill | 17 | today | MIT | A | 54 | Claude Code |
| validate-motionMasterPlayspots/motionspec | Skill | 2 | 3d ago | MIT | A | 52 | Claude Code, Codex |
| motiscope-analyzeKumarSashank/motiscope | Skill | 129 | 3mo ago | MIT | B | 103 | Claude Code |