proof-of-human

proof-of-human is a skill for Claude Code from sanctifai/skills. It costs 83 tokens per session (1,733 once invoked), scanned A, original, Apache-2.0.

A workflow for obtaining cryptographic proof that a qualified human approved an action. It asks a person to approve in a web browser, then returns a certificate that records their participation.

In plain words
What is it for?
Use it for approval gates, regulated operations, and other tasks where a verifiable human decision is required.
Why use it?
It provides evidence of human involvement when an agent must request approval, handle a regulated action, or send work outside the current session.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin.

Part of the sanctifai-trust plugin — 1 skill shipped together

Good fit Use it for approval gates, regulated operations, and other tasks where a verifiable human decision is required.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/sanctifai/skills/proof-of-human
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 sanctifai/skills --skill proof-of-human
Clone the repo
git clone --depth 1 https://github.com/sanctifai/skills

Made for: Claude Code.

Or install sanctifai-trust, the plugin that ships this one along with the rest of its 1 skill.

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 proof-of-human

README.md
[![agentmods](https://agentmods.dev/badge/skills/sanctifai/skills/proof-of-human/github.svg)](https://agentmods.dev/skills/sanctifai/skills/proof-of-human)
Your own site
<a href="https://agentmods.dev/skills/sanctifai/skills/proof-of-human"><img src="https://agentmods.dev/badge/skills/sanctifai/skills/proof-of-human/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 proof-of-human

Your own site · 80×15
<a href="https://agentmods.dev/skills/sanctifai/skills/proof-of-human"><img src="https://agentmods.dev/badge/skills/sanctifai/skills/proof-of-human.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 83 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,733 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.
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 $0.00083 $0.01733
Opus 5 $0.00042 $0.00866
Sonnet 5 $0.00017 $0.00347
Haiku 4.5 $0.00008 $0.00173

Measured 2d ago against content hash 48a2eea58f22, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade A, and why

proof-of-human 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 2d 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.

plugins/sanctifai-trust/skills/proof-of-human/SKILL.md · 189 lines

How it starts

The opening of the file, as written. The whole thing — 189 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Proof of Human

SanctifAI Trust Chat bridge — one of three Trust surfaces (Embedded, Chrome extension, Chat bridge). All three produce the same participation + certificate_url. This skill is the chat path: you cannot run WebAuthn in-card, so you mint here, a human opens Chrome, and you poll for the cert.

Default APP_BASE_URL: https://bridge.trust.sanctifai.com

Always use the approve_url the API returns. Never invent localhost links. The agent never holds TRUST_API_KEY — the hosted bridge does. Self-host this plugin only if you need a custom allowlisted origin.

Embedded and Extension: https://trust.sanctifai.com/agents/trust/skill.md

Flow

1. POST {APP_BASE_URL}/api/v1/attestations
2. Give the human approve_url — they open it in Chrome
3. Poll GET {APP_BASE_URL}/api/v1/attestations/{id}
   or GET {APP_BASE_URL}/api/v1/attestations/{id}/wait
4. When status is completed, paste certificate_url

1. Create

POST {APP_BASE_URL}/api/v1/attestations

{
  "task_type": "GEN",
  "domain": "GEN",
  "task_subtype": "Chat approval",
  "requesting_agent": "Sebastian - Dev Bot",
  "taskData": { "summary": "opaque task payload" },
  "resultData": { "decision": "approved" }
}

task_type and domain are 3-letter taxonomy codes. Put a short title in task_subtype (max 200 chars). Optional requesting_agent is a short display string (max 120 chars) shown on the approve page so the human can see which agent asked for Proof of Human. Empty or whitespace-only values are omitted. Do not put PII in any field — the certificate URL is public.

Response:

{
  "attestation_id": "uuid",
  "approve_url": "https://bridge.trust.sanctifai.com/approve?token=...",
  "status": "pending"
}

2. Human step (Chrome)

Tell the human:

Open this HTTPS link in Chrome and confirm with your device passkey: {approve_url}

The page talks to https://trust.sanctifai.com through this plugin (presence/start, presence/options, presence/verify). If Trust returns 404 / "no credentials", the page enrolls a passkey on this origin and retries.

Read the full file on GitHub · 189 lines

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. 2d ago Changed 48a2eea58f22
  2. 3d ago First seen · 189 lines · 83 tokens per session scan A 0e16539579a1

Subscribe to this mod's changes

proof-of-human is a skill published in the GitHub repository sanctifai/skills (6 stars, last pushed 2d ago), licensed Apache-2.0. It adds 83 tokens to every session and 1,733 once invoked, about $0.0004 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 2026-09-09.

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