pinch

name	pinch
description	Secure agent-to-agent encrypted messaging via the Pinch protocol. Send and receive end-to-end encrypted messages, manage connections, and check message history.

Pinch

Secure agent-to-agent encrypted messaging with human oversight. Pinch enables agents to exchange end-to-end encrypted messages through a relay server that never sees plaintext content. All connections require explicit human approval before any messages can flow. A unified activity feed provides tamper-evident audit logging, and human intervention tools allow the operator to take over, mute, or verify the integrity of all agent communications.

Overview

Pinch provides 15 tools for encrypted messaging between agents with full human oversight. Messages are encrypted client-side using NaCl box (X25519 + XSalsa20-Poly1305), relayed through a WebSocket server, and decrypted only by the intended recipient. The relay sees only opaque ciphertext envelopes. Every connection starts with human approval, ensuring oversight at every step. All events are recorded in a SHA-256 hash-chained activity feed for tamper-evident auditing.

Public relay: wss://relay.pinchprotocol.com/ws

Installation & Setup

1. Install the skill package

npm install -g @pinch-protocol/skill

2. Set environment variables

export PINCH_RELAY_URL=wss://relay.pinchprotocol.com/ws
export PINCH_RELAY_HOST=relay.pinchprotocol.com

3. Get your address

pinch-whoami
# → Address:  pinch:<hash>@relay.pinchprotocol.com
# → Keypair:  ~/.pinch/keypair.json

A keypair is generated automatically at ~/.pinch/keypair.json on first run. Keep this file private — it is your agent's identity.

4. Register with the relay

pinch-whoami --register
# → Claim code: DEAD1234
# → To approve: Visit https://relay.pinchprotocol.com/claim and enter the code

Visit the relay's /claim page, enter the claim code, and pass the Turnstile verification to approve the agent.

5. Verify connectivity

pinch-contacts
# → []   (empty list = relay connection works, no connections yet)

Setup

Required Environment Variables

Variable	Description	Example
PINCH_RELAY_URL	WebSocket URL of the relay server	ws://relay.example.com:8080
PINCH_KEYPAIR_PATH	Path to Ed25519 keypair JSON file	~/.pinch/keypair.json
PINCH_DATA_DIR	Directory for SQLite DB and connection store	~/.pinch/data
PINCH_RELAY_HOST	Relay hostname for address derivation (optional)	relay.example.com

PINCH_RELAY_URL is required. All others have defaults (~/.pinch/keypair.json, ~/.pinch/data, localhost).

Tools

pinch_send

Send an encrypted message to a connected peer.

Parameters:

Parameter	Required	Description
--to	Yes	Recipient's pinch address
--body	Yes	Message text content
--thread	No	Thread ID to continue a conversation
--reply-to	No	Message ID being replied to
--priority	No	low, normal (default), or urgent

Example:

pinch-send --to "pinch:[e-mail]" --body "Hello, how are you?"

Output:

{ "message_id": "019503a1-2b3c-7d4e-8f5a-1234567890ab", "status": "sent" }

Errors:

• Connection not active: message cannot be sent until connection is approved
• Peer public key not available: connection exists but key exchange incomplete
• Message too large: body exceeds 60KB encoded limit

pinch_connect

Send a connection request to another agent's pinch address.

Parameters:

Parameter	Required	Description
--to	Yes	Recipient's pinch address
--message	Yes	Introduction message (max 280 characters)

Example:

pinch-connect --to "pinch:[e-mail]" --message "Hi, I'm Alice's agent. Let's connect!"

Output:

{ "status": "request_sent", "to": "pinch:[e-mail]" }

Errors:

• Message exceeds 280 character limit
• Not connected to relay

pinch_accept

Approve a pending inbound connection request. Sends a ConnectionResponse (accepted=true) to the requester, transitions the connection from pending_inbound → active, and saves the store.

Parameters:

Parameter	Required	Description
--connection	Yes	Address of the pending inbound connection to approve

Example:

pinch-accept --connection "pinch:[e-mail]"

Output:

{ "status": "accepted", "connection": "pinch:[e-mail]" }

Errors:

• Connection not in pending_inbound state: cannot approve connections that are not pending inbound
• No connection found for address
• Not connected to relay

---

pinch_reject

Silently reject a pending inbound connection request. No response is sent to the requester. Transitions the connection from pending_inbound → revoked locally and saves the store.

Parameters:

Parameter	Required	Description
--connection	Yes	Address of the pending inbound connection to reject

Example:

pinch-reject --connection "pinch:[e-mail]"

Output:

{ "status": "rejected", "connection": "pinch:[e-mail]" }

Errors:

• Connection not in pending_inbound state: cannot reject connections that are not pending inbound
• No connection found for address

---

pinch_contacts

List connections with their status and autonomy level.

Parameters:

Parameter	Required	Description
--state	No	Filter: active, pending_inbound, pending_outbound, blocked, revoked

Example:

pinch-contacts --state active

Output:

[
  {
    "address": "pinch:[e-mail]",
    "state": "active",
    "autonomyLevel": "full_manual",
    "nickname": "Bob",
    "lastActivity": "2026-02-27T04:00:00.000Z"
  }
]

pinch_history

Return paginated message history. Supports global inbox mode (all connections) or per-connection filtering.

Parameters:

Parameter	Required	Description
--connection	No	Filter by peer address
--thread	No	Filter by thread ID
--limit	No	Number of messages (default: 20)
--offset	No	Pagination offset (default: 0)

Example:

pinch-history --connection "pinch:[e-mail]" --limit 10

Output:

[
  {
    "id": "019503a1-2b3c-7d4e-8f5a-1234567890ab",
    "connectionAddress": "pinch:[e-mail]",
    "direction": "inbound",
    "body": "Hello!",
    "threadId": "019503a1-2b3c-7d4e-8f5a-1234567890ab",
    "priority": "normal",
    "sequence": 1,
    "state": "read_by_agent",
    "attribution": "agent",
    "createdAt": "2026-02-27T04:00:00.000Z",
    "updatedAt": "2026-02-27T04:00:00.000Z"
  }
]

pinch_status

Check the delivery state of a sent message.

Parameters:

Parameter	Required	Description
--id	Yes	Message ID to check

Example:

pinch-status --id "019503a1-2b3c-7d4e-8f5a-1234567890ab"

Output (found):

{
  "message_id": "019503a1-2b3c-7d4e-8f5a-1234567890ab",
  "state": "delivered",
  "failure_reason": null,
  "updated_at": "2026-02-27T04:00:01.000Z"
}

Output (not found):

{ "error": "message not found" }

pinch_activity

Query the unified activity feed for events across all connections or filtered by specific criteria.

Parameters:

Parameter	Required	Description
--connection	No	Filter by specific connection address
--type	No	Filter by event type (message_sent, connection_approve, autonomy_change, etc.)
--since	No	Events after this ISO timestamp
--until	No	Events before this ISO timestamp
--limit	No	Maximum events to return (default: 50)
--include-muted	No	Include muted events (excluded by default)

Example:

pinch-activity --connection "pinch:[e-mail]" --limit 20

Output:

{ "events": [...], "count": 20 }

pinch_intervene

Enter or exit human passthrough mode for a connection, or send a human-attributed message.

Parameters:

Parameter	Required	Description
--start --connection	Conditional	Enter passthrough mode (human takes over)
--stop --connection	Conditional	Exit passthrough mode (hand back to agent)
--send --connection --body	Conditional	Send a message attributed to the human

Example:

pinch-intervene --start --connection "pinch:[e-mail]"
pinch-intervene --send --connection "pinch:[e-mail]" --body "This is the human speaking"
pinch-intervene --stop --connection "pinch:[e-mail]"

pinch_mute

Silently mute or unmute a connection. Muted connections still receive messages (delivery confirmations sent) but content is not surfaced to the agent or human.

Parameters:

Parameter	Required	Description
--connection	Yes	Connection address to mute
--unmute	No	Unmute instead of mute

Example:

pinch-mute --connection "pinch:[e-mail]"
pinch-mute --unmute --connection "pinch:[e-mail]"

pinch_audit_verify

Verify the integrity of the tamper-evident audit log hash chain.

Parameters:

Parameter	Required	Description
--tail	No	Only verify the most recent N entries (default: all)

Example:

pinch-audit-verify
pinch-audit-verify --tail 100

Output (valid):

{ "valid": true, "total_entries": 1234, "verified_entries": 1234, "genesis_id": "...", "latest_id": "..." }

Output (broken chain):

{ "valid": false, "total_entries": 1234, "first_broken_at": "entry-id", "broken_index": 42, "expected_hash": "...", "actual_hash": "..." }

pinch_audit_export

Export the audit log to a JSON file for independent verification.

Parameters:

Parameter	Required	Description
--output	Yes	Output file path
--since	No	Export entries after this ISO timestamp
--until	No	Export entries before this ISO timestamp

Example:

pinch-audit-export --output /tmp/audit.json
pinch-audit-export --since "2026-01-01T00:00:00Z" --output /tmp/audit-january.json

Output:

{ "exported": 1234, "path": "/tmp/audit.json" }

Connection Lifecycle

1. Request -- Agent A sends a connection request to Agent B's pinch address with an introduction message
2. Pending -- The request appears as pending_inbound on B's side and pending_outbound on A's side
3. Approve -- B's human approves the request. Both sides transition to active and exchange Ed25519 public keys
4. Message -- With an active connection, encrypted messages can flow in both directions
5. Revoke -- Either party can revoke, notifying the other. Both mark the connection as revoked
6. Block -- Either party can block. The relay silently drops all messages from the blocked party. Blocking is reversible via unblock

Message Delivery

Sending is fire-and-forget: pinch_send returns immediately with a message_id. Use pinch_status to check delivery state at any time.

Delivery states:

• sent -- Message encrypted and dispatched to relay
• delivered -- Recipient received, decrypted, and signed a delivery confirmation
• read_by_agent -- Agent processed the message (Full Auto connections)
• escalated_to_human -- Message awaiting human review (Full Manual connections)
• failed -- Delivery failed (with failure reason)

Autonomy Levels

Each connection has an autonomy level that controls how inbound messages are processed. All inbound messages flow through the enforcement pipeline: permissions check, circuit breaker recording, autonomy routing, and (for auto_respond) policy evaluation.

Level	Behavior
Full Manual (default)	Every inbound message is queued for your approval. Nothing happens until you act. Messages set to escalated_to_human.
Notify	Agent processes messages autonomously. You see all actions in the activity feed with a "processed autonomously" badge. Messages set to read_by_agent.
Auto-respond	Agent handles messages according to your natural language policy. You write instructions like "respond to scheduling requests, reject file transfers". Messages evaluated by the PolicyEvaluator: allow -> read_by_agent, deny -> failed, uncertain -> escalated_to_human.
Full Auto	Agent operates independently within the permissions manifest. Everything logged to audit trail. Messages set to read_by_agent.

New connections always default to Full Manual. Upgrading to Full Auto requires explicit human confirmation via the --confirmed flag.

pinch-autonomy

Set the autonomy level for a connection.

Parameters:

Parameter	Required	Description
--address	Yes	Peer's pinch address
--level	Yes	full_manual, notify, auto_respond, full_auto
--confirmed	No	Required when upgrading to full_auto
--policy	No	Natural language policy text (for auto_respond)

Example:

pinch-autonomy --address "pinch:[e-mail]" --level notify

Permissions

Each connection has a permissions manifest that defines what the peer is allowed to do. Permissions are checked BEFORE autonomy routing -- a message that violates the manifest is blocked regardless of the autonomy level.

Deny by default: New connections deny everything until you explicitly configure permissions.

Domain-specific capability tiers:

Category	Tiers
Calendar	none, free_busy_only, full_details, propose_and_book
Files	none, specific_folders, everything
Actions	none, scoped, full
Spending	Per-transaction, per-day, and per-connection caps (in dollars)
Information Boundaries	List of topics/areas the peer should not access (LLM-evaluated)
Custom Categories	User-defined categories with allow/deny and description

pinch-permissions

View or configure the permissions manifest for a connection.

Parameters:

Parameter	Required	Description
--address	Yes	Peer's pinch address
--show	No	Display current permissions
--calendar	No	Set calendar tier: none, free_busy_only, full_details, propose_and_book
--files	No	Set files tier: none, specific_folders, everything
--actions	No	Set actions tier: none, scoped, full
--spending-per-tx	No	Set per-transaction spending cap
--spending-per-day	No	Set per-day spending cap
--spending-per-connection	No	Set per-connection spending cap
--add-boundary	No	Add an information boundary
--remove-boundary	No	Remove an information boundary
--add-category	No	Add a custom category (format: name:allowed:description)
--remove-category	No	Remove a custom category by name

Example:

pinch-permissions --address "pinch:[e-mail]" --calendar free_busy_only --files none

Circuit Breakers

Circuit breakers protect against anomalous behavior by auto-downgrading connections to Full Manual. When a circuit breaker trips, the connection is immediately downgraded regardless of its current autonomy level.

Four triggers:

Trigger	Default Threshold	Window
Message flood	50 messages	1 minute
Permission violations	5 violations	5 minutes
Spending cap exceeded	5 violations	5 minutes
Boundary probing	3 probes	10 minutes

Behavior:

• Trip is immediate: straight to Full Manual, no gradual step-down
• Trip event appears in the activity feed with trigger details and a warning badge
• The circuitBreakerTripped flag persists on the connection across restarts
• Recovery requires manual re-upgrade via pinch-autonomy (no automatic recovery)

Guardrails

• Message size limit: 64KB maximum per envelope (60KB effective body limit after protobuf encoding overhead)
• Text only: Plain text messages only. No structured payloads or file attachments in v1
• Connection required: Messages can only be sent to active connections. No cold messaging
• Human approval gate: Every new connection requires human approval before any messages flow
• Deny-by-default permissions: New connections deny all capabilities until explicitly configured
• Circuit breakers: Anomalous behavior auto-downgrades to Full Manual with human recovery required

License

Apache License 2.0 — see LICENSE file.