dsh-human-intent

Human intent verification and cryptographic action authorization for AI agents.

AI can propose an action. Only a human can authorize it.

Agent proposes Action
        ↓
Canonicalize Action
        ↓
Hash Exact Intent
        ↓
Human sees exact Action
        ↓
Human verifies (WebAuthn: Touch ID / Windows Hello / passkey)
        ↓
Cryptographically sign Intent
        ↓
Generate Intent Receipt
        ↓
Verify exact Action binding
        ↓
Execute

Why

AI agents can increasingly execute real-world actions: delete data, deploy services, spend money, send messages. An agent having the capability to run a tool does not mean a human granted the authority to run it.

Capability != Authority.

Existing human-in-the-loop mechanisms usually verify a fuzzy fact — "a human touched the sensor" — and then hand the agent a blanket verified = true, often valid for a window of time. Nothing binds the approval to the exact action. An approval obtained for rm -rf ./test-data silently authorizes rm -rf ./production-data.

dsh-human-intent closes that gap. Every authorization is:

• Exact-action-bound — the approval is hashed and signed over the precise tool, target and arguments; any mutation invalidates it.
• Cryptographically signed — WebAuthn (platform authenticator, passkey, or security key) with full server-side verification.
• One-shot — an authorization authorizes exactly one execution.
• Expiring — requests and receipts carry a short validity window.
• Auditable — every transition is recorded in a local append-only log.

This project is not a fingerprint-identification system and does not identify a specific natural person. WebAuthn platform authenticators (Touch ID / Windows Hello / passkeys) prove that the holder of a registered credential performed a user-verification gesture. That proof is what gets bound to the action. See Security Model.

How It Works

1. The agent (or a tools/pre-execute policy hook) proposes an IntentRequest: tool, operation, target, arguments, risk, reason.
2. The request is canonically serialized (RFC 8785 JCS) and hashed: intentHash = SHA-256(canonical intent).
3. The human opens the approval page and sees the exact action.
4. Approving triggers a WebAuthn ceremony whose challenge is the intentHash itself — the authenticator signs the bytes of the action.
5. The server fully verifies the assertion (challenge, origin, RP ID, public key signature, counter, user-verification flag) and issues an IntentReceipt.
6. Before execution, the receipt is consumed: the action is re-hashed and must match, the signature is re-verified against the stored credential, and the one-shot consumption marker is checked. Only then does the tool run — exactly once, for exactly that action.

Quick Start

Requirements: Node.js ≥ 20.11.

npm install
npm run verify        # build + lint + tests + http smoke test
npm run demo          # interactive acceptance scenarios A–E

Demo walkthrough (the part you show people):

npm run demo

• No passkey yet? The browser opens and you register one (Touch ID on macOS, Windows Hello on Windows).
• Pick a scenario; the agent proposes a destructive command, the browser shows the exact action, you approve or deny, and the terminal prints the cryptographic outcome — including the mutation, replay and expiry attacks being rejected.

Run the approval server standalone:

npm run serve                       # http://localhost:8787
node bin/dsh-human-intent.js serve --port 9000 --data-dir ./data

Inspect a receipt (validates structure, integrity and signature):

node bin/dsh-human-intent.js inspect receipt.json

Read the audit log:

node bin/dsh-human-intent.js audit

DSH Plugin

Inside DeepSeek Harness (DSH), the plugin provides:

• human_intent_request — propose an action, wait for the human, receive an IntentReceipt (or an explicit denial).
• human_intent_verify — verify a receipt authorizes one exact action before executing it.
• human_intent_status — enforcement status.
• tools/pre-execute policy enforcement for protectedTools.
• A settings slot and a Better Sidebar approval panel (WebAuthn in the DSH web UI), plus a loopback API under /human-intent/api.

{
  "protectedTools": ["shell.exec", "kubectl.*"],
  "rules": [{ "tool": "shell.exec", "risk": "high" }]
}

Glob semantics: shell.* matches one dot-segment (shell.exec, not shell.exec.sub); shell.** spans segments. Exact names always work.

Local development:

npm install
npm run build:client
dsh plugin --profile web add link:/Users/you/dsh-human-intent

The DSH client UI must be served from localhost for WebAuthn to be available, and the DSH host origin must be listed in allowedOrigins.

Configuration

IntentRequest

interface IntentRequest {
  version: "0.1"
  requestId: string          // unique per request
  intentHash: string         // SHA-256 over the canonical intent
  nonce: string              // 256-bit unguessable, one per request
  action: {
    tool: string             // e.g. "shell.exec"
    operation?: string
    target?: string          // e.g. "namespace/prod/pod/foo"
    arguments: object        // exact arguments
  }
  context?: {
    description?: string
    reason?: string
    risk?: "low" | "medium" | "high" | "critical"
  }
  agent?: { id?: string; name?: string }
  session?: { id?: string }
  issuedAt: string           // ISO 8601
  expiresAt: string          // ISO 8601
}

IntentReceipt

interface IntentReceipt {
  kind: "IntentReceipt"
  version: "0.1"
  requestId: string
  intentHash: string          // the action this receipt authorizes
  decision: "approved" | "denied"
  intent: IntentRequest       // embedded, integrity-checked
  authenticator: { type: "webauthn"; credentialId: string }
  verification: { method: "webauthn"; userVerified: boolean }
  signedAt: string
  expiresAt: string           // same window as the request
  nonce: string
  assertion?: { /* raw WebAuthn assertion for re-verification */ }
  deniedReason?: string
}

Receipts serialize, verify and audit (docs/PROTOCOL.md).

Security Model

What this project guarantees, precisely:

1. Action binding. Approving tool=A, args=X produces a receipt that cannot authorize tool=A, args=Y or tool=B, args=X. The intentHash covers tool, operation, target, arguments, nonce, requestId and the validity window.
2. Signature coverage. The WebAuthn challenge is the intentHash, so the authenticator's signature covers the exact action bytes.
3. Full server-side verification. Challenge, origin allowlist, RP ID, credential public key (COSE/ES256 or RS256), signature, signature counter (clone detection) and the user-verification flag are all verified with @simplewebauthn/server. No client-provided verified: true is ever trusted.
4. One-shot consumption. A consumed receipt is rejected on reuse — in memory and, when a data dir is configured, across restarts via the audit log.
5. Expiry. Requests and receipts share a short window; after it, only a fresh human authorization works.
6. Explicit denial. Denials are first-class outcomes the agent can read.

What this project does not claim:

• It does not identify which natural person is enrolled on the device. WebAuthn proves a registered credential holder verified — see docs/THREAT_MODEL.md for the full model.
• It cannot stop a human from approving a misleading reason string if the arguments are honest; the UI shows raw arguments and the hash, never just a summary.
• The local audit log is append-only JSONL; it is not tamper-proof against a host compromise (future work: signed logs).

Architecture

Agent
  ↓ IntentRequest
Canonicalizer (RFC 8785 JCS)
  ↓ CanonicalIntent
Hasher (SHA-256)
  ↓ IntentHash
Human Intent UI (exact action, risk, arguments, expiry)
  ↓ WebAuthn ceremony (challenge = intentHash)
Verifier (@simplewebauthn/server: origin, RP, key, signature, counter, UV)
  ↓ IntentReceipt
Policy / Consumption Gate (action re-hash, one-shot, expiry)
  ↓
Tool Execution (exactly the authorized action)

Details: docs/ARCHITECTURE.md · Protocol: docs/PROTOCOL.md · Threats: docs/THREAT_MODEL.md

Demo

npm run demo runs the five acceptance scenarios:

Migration from dsh-fingerprint-signature

dsh-human-intent evolved from dsh-fingerprint-signature, which gated protected tools behind a platform user-verification popup and granted a 30-second blanket pass. That design verified human presence but nothing about which action the human was approving.

This project keeps the plugin structure and the loopback-API pattern that worked there, and replaces the security model:

The signature-variable feature (names, identity IDs, custom variables injected into the agent context) is not migrated: it is a different use case. Keep using dsh-fingerprint-signature for it; both plugins can be installed side by side.

See docs/MIGRATION.md.

Roadmap

• v0.1 — WebAuthn human intent, exact action binding, intent receipts, protected tools, audit log, DSH plugin, CLI + demo.
• v0.2 — passkey sync/hardware-key profiles, richer policy rules, MCP adapter.
• v0.3 — multi-party approval, organization policies, remote approval, receipt transparency.
• Future — cross-agent human-intent protocol, SDKs, browser and infrastructure integrations.

Limitations

• v0.1 stores credentials in a local JSON file; there is no per-user account model or encrypted keystore yet.
• The DSH client approval panel requires a localhost-served UI and a WebAuthn-capable browser.
• Single-host enforcement: receipts are consumed on the host that issued them (no distributed consumption ledger).
• Tests use a software authenticator with real EC P-256 keys; physical authenticator behavior (resident keys, hybrid transport) is exercised in the demo, not the test suite.

License

MIT — see LICENSE.