name: synapse-a2a
description: This skill provides comprehensive guidance for inter-agent communication using the Synapse A2A framework. Use this skill when sending messages to other agents, routing @agent patterns, understanding priority levels, handling A2A protocol operations, managing task history, configuring settings, or using File Safety features for multi-agent coordination. Automatically triggered when agent communication, A2A protocol tasks, history operations, or file safety operations are detected.

Synapse A2A Communication

Inter-agent communication framework via Google A2A Protocol.

Quick Reference

Tip: Run synapse list before sending to verify the target agent is READY.

Sending Messages (Recommended)

Use synapse send command for inter-agent communication. This works reliably from any environment including sandboxed agents.

synapse send gemini "Please review this code" --from claude
synapse send claude "What is the status?" --from codex
synapse send codex-8120 "Fix this bug" --priority 3 --from gemini

Important: Always use --from to identify yourself so the recipient knows who sent the message and can reply.

Target Resolution (Matching Priority):
1. Exact ID: synapse-claude-8100 (direct match)
2. Type-port: claude-8100, codex-8120, opencode-8130, copilot-8140 (shorthand)
3. Type only: claude, gemini, codex, opencode, copilot (only if single instance)

Note: When multiple agents of the same type are running, type-only targets (e.g., claude) will fail with an ambiguity error. Use type-port shorthand (e.g., claude-8100) instead.

Choosing --response vs --no-response

Rule: If your message asks for a reply, use --response

# Question - needs reply
synapse send gemini "What is the best approach?" --response --from claude

# Delegation - no reply needed
synapse send codex "Run tests and fix failures" --from claude

Roundtrip Communication (--response)

For request-response patterns:

# Sender: Wait for response (blocks until reply received)
synapse send gemini "Analyze this data" --response --from claude

# Receiver: Reply to the sender
synapse reply "Analysis result: ..." --from gemini

The --response flag makes the sender wait. The receiver should reply using the synapse reply command.

Reply Tracking: Synapse automatically tracks senders who expect a reply ([REPLY EXPECTED] messages). Use synapse reply for responses - it automatically knows who to reply to.

Receiving and Replying to Messages

When you receive an A2A message, it appears with the A2A: prefix:

Message Formats:

A2A: [REPLY EXPECTED] <message>   <- Reply is REQUIRED
A2A: <message>                    <- Reply is optional (delegation/notification)

If [REPLY EXPECTED] marker is present, you MUST reply using synapse reply.

Reply Tracking: Synapse stores sender info only for messages with [REPLY EXPECTED] marker. Multiple senders can be tracked simultaneously (each sender has one entry).

Replying to messages:

# Use the reply command (--from is required in sandboxed environments)
synapse reply "Here is my analysis..." --from <your_agent_type>

Example - Question received (MUST reply):

Received: A2A: [REPLY EXPECTED] What is the project structure?
Reply:    synapse reply "The project has src/, tests/..." --from codex

Example - Delegation received (no reply needed):

Received: A2A: Run the tests and fix failures
Action:   Just do the task. No reply needed unless you have questions.

Priority Levels

# Normal priority (default)
synapse send gemini "Analyze this"

# Higher priority
synapse send claude "Urgent review needed" --priority 4

# Emergency interrupt
synapse send codex "STOP" --priority 5

Agent Status

Verify before sending: Run synapse list and confirm the target agent's Status column shows READY:

synapse list
# Output:
# NAME                  TYPE    STATUS      PORT   WORKING_DIR
# synapse-claude-8100   claude  READY       8100   my-project
# synapse-gemini-8110   gemini  WAITING     8110   my-project  # <- needs user input
# synapse-codex-8120    codex   PROCESSING  8120   my-project  # <- busy

Status meanings:
- READY: Safe to send messages
- WAITING: Agent needs user input - use terminal jump (see below) to respond
- PROCESSING: Busy, wait or use --priority 5 for emergency interrupt
- DONE: Recently completed, will return to READY shortly

Interactive Controls

In synapse list, you can interact with agents:

Supported Terminals:
- iTerm2 (macOS) - Switches to correct tab/pane
- Terminal.app (macOS) - Switches to correct tab
- Ghostty (macOS) - Activates application
- VS Code integrated terminal - Opens to working directory
- tmux - Switches to agent's session
- Zellij - Focuses agent's terminal pane

Use case: When an agent shows WAITING status, use terminal jump to quickly respond to its selection prompt.

Key Features

• Agent Communication: synapse send command, priority control, response handling
• Task History: Search, export, statistics (synapse history)
• File Safety: Lock files to prevent conflicts (synapse file-safety)
• Settings: Configure via settings.json (synapse init)
• Approval Mode: Control initial instruction approval (approvalMode in settings)

References

For detailed documentation, read:

• references/commands.md - Full CLI command reference
• references/file-safety.md - File Safety detailed guide
• references/api.md - A2A endpoints and message format
• references/examples.md - Multi-agent workflow examples