vital-sign-extraction

vital-sign-extraction is a skill for Claude Code, Codex from benchflow-ai/skillsbench. It costs 128 tokens per session (1,077 once invoked), scanned A, original, Apache-2.0.

A signal-analysis workflow that estimates heart rate and breathing rate from an already cleaned one-dimensional body-signal recording. It can use signals such as radar phase, WiFi channel measurements, PPG, piezo sensors, or chest movement.

In plain words
What is it for?
Use it to separate breathing and heart-rate bands, estimate their peak frequencies, convert them to beats or breaths per minute, reject a likely second harmonic, and compare the result with autocorrelation.
Why use it?
A cleaned signal still contains separate breathing and heartbeat rhythms, noise, and sometimes a heartbeat harmonic that looks stronger than the true rhythm. The workflow filters the ranges, selects likely frequencies, rejects that common error, and cross-checks the result.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit Use it to separate breathing and heart-rate bands, estimate their peak frequencies, convert them to beats or breaths per minute, reject a likely second harmonic, and compare the result with autocorrelation.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/benchflow-ai/skillsbench/vital-sign-extraction
About the project

SkillsBench is a benchmark for measuring how effectively AI agents use modular skills—folders containing instructions, scripts, and resources—to complete specialized tasks. It helps researchers and developers evaluate both skill quality and agent behavior, including tasks that require combining multiple skills. The catalogue’s skills and instructions are evaluated as part of this workflow.

benchflow-ai/skillsbench · 1,764 stars · on GitHub · skillsbench.ai

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent
npx skills add benchflow-ai/skillsbench --skill vital-sign-extraction
Clone the repo
git clone --depth 1 https://github.com/benchflow-ai/skillsbench

Made for: Claude Code, Codex.

Wrote 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.

agentmods badge for vital-sign-extraction

README.md
[![agentmods](https://agentmods.dev/badge/skills/benchflow-ai/skillsbench/vital-sign-extraction/github.svg)](https://agentmods.dev/skills/benchflow-ai/skillsbench/vital-sign-extraction)
Your own site
<a href="https://agentmods.dev/skills/benchflow-ai/skillsbench/vital-sign-extraction"><img src="https://agentmods.dev/badge/skills/benchflow-ai/skillsbench/vital-sign-extraction/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.

agentmods 80×15 button for vital-sign-extraction

Your own site · 80×15
<a href="https://agentmods.dev/skills/benchflow-ai/skillsbench/vital-sign-extraction"><img src="https://agentmods.dev/badge/skills/benchflow-ai/skillsbench/vital-sign-extraction.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 128 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,077 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe. Third-party audits
  • NVIDIA SkillSpector pass 7 Sept 2026
How audits are shown
Origin original No closer match found in the catalogue.
Token cost

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.

ModelPer sessionOnce invoked
Fable 5.1 $0.00128 $0.01077
Opus 5 $0.00064 $0.00539
Sonnet 5 $0.00026 $0.00215
Haiku 4.5 $0.00013 $0.00108

Measured 9d ago against content hash aff09b876c5c, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-12, from the pricing page.

Security

Grade A, and why

vital-sign-extraction 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 9d 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.

Origin

Copies of this mod

1 near-identical copy found in the catalogue:

tasks/radar-vital-signs/environment/skills/vital-sign-extraction/SKILL.md · 73 lines

How it starts

The opening of the file, as written. The whole thing — 73 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Vital-Sign Extraction

Given a cleaned 1-D periodic signal (radar phase, WiFi CSI, PPG, piezo), estimate heart rate and breathing rate in bpm.

Upstream ingestion of radar captures is the radar-signal-processing skill. This skill picks up after a 1-D signal is extracted.

Pipeline (do every step)

  1. Split into BR and HR bands with two separate bandpasses:
    • BR: butter(4, [0.08, 0.5], btype='band', fs=fs) — 4.8–30 bpm
    • HR: butter(4, [0.7, 3.0], btype='band', fs=fs) — 42–180 bpm
  2. Peak frequency via zero-padded Welch PSD:
    nperseg = min(len(x), int(fs * 25))
    f, p = welch(x, fs=fs, nperseg=nperseg, noverlap=nperseg//2,
                 nfft=8*nperseg, detrend='constant')
    in_band = (f >= lo) & (f <= hi)
    peak_hz = f[in_band][np.argmax(p[in_band])]
    
  3. HR harmonic rejection — always run:
    f_sub = f_peak / 2.0
    if 0.7 <= f_sub <= 3.0:
        p_sub = np.interp(f_sub, f, p)
        p_top = np.interp(f_peak, f, p)
        if p_sub > 0.5 * p_top:
            f_peak = f_sub          # the peak was the 2nd harmonic
    hr_bpm = f_peak * 60
    
  4. Cross-check with autocorrelation:
    ac = np.correlate(x - x.mean(), x - x.mean(), mode='full')
    ac = ac[len(ac)//2:] / ac[len(ac)//2]
    lag = int(fs/f_hi) + np.argmax(ac[int(fs/f_hi):int(fs/f_lo)])
    bpm_ac = 60 * fs / lag
    
    If abs(bpm_ac - bpm_psd) > 5, flag as low confidence.

Decision rules

If Then
f_peak/2 in HR band and p_sub > 0.5 × p_top Pick sub-harmonic (fundamental)
PSD and autocorrelation disagree by > 5 bpm Flag low confidence; do not commit to one value
BR estimate < 10 bpm (slow breather) Expect HR-band contamination — see references/harmonic-pitfalls.md
HR > 150 bpm (tachycardia) Widen HR band upper to 3.3 Hz, re-estimate
Clip < 15 s long PSD bin spacing > tolerance — prefer autocorrelation or flag inconclusive

Sanity checks before reporting

Read the full file on GitHub · 73 lines

Files

What ships with it

2 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

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.

  1. 9d ago First seen · 73 lines · 128 tokens per session scan A aff09b876c5c

Subscribe to this mod's changes

vital-sign-extraction is a skill published in the GitHub repository benchflow-ai/skillsbench (1,764 stars, last pushed 1mo ago), licensed Apache-2.0. It adds 128 tokens to every session and 1,077 once invoked, about $0.0006 per session on Opus 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 2026-09-03.