a2a-client（A2A 客户端）

A2A Client — Agent-to-Agent Task Routing

Discover and interact with other agents through the A2A API Gateway's A2A (Agent-to-Agent) API. Send tasks, check results, and route work to the right agent.

Sidecar Principle

This skill is strictly an OpenClaw sidecar — it talks TO the A2A API Gateway using the gateway's existing API format. The gateway's endpoints are the contract; OpenClaw is just a participant. Never assume what the other end looks like — it could be MC2, another OpenClaw, or anything else that speaks A2A. These scripts consume the gateway's API as-is.

Configuration

All scripts read from a shared a2a.conf file (located in this skill directory). The gateway URL must be configured before use — there are no hardcoded defaults.

Priority order: CLI flags → env vars → a2a.conf → auto-detected defaults

Run a2a-register/a2a-setup.sh to create your config interactively, or manually create a2a-client/a2a.conf:

A2A_GATEWAY_URL="http://YOUR_GATEWAY_IP:8090"
A2A_GATEWAY_API_KEY="your-key-here"
AGENT_SLUG="your-hostname"

If A2A_GATEWAY_URL is not set anywhere, scripts will exit with an error message.

When to Use

• Discover agents/providers — Before sending tasks, or when the user asks about available agents or LLM providers
• Send tasks — When delegating work to another agent via the gateway, or when another agent's capabilities are better suited
• Check task results — When tracking a previously sent task or retrieving completed results
• Route to specific agents — When a task should be handled by a particular A2A agent (use --target-agent)

Authentication

All scripts automatically obtain an admin JWT from the gateway (GET /v0/admin/bootstrap). The gateway uses this JWT for API authentication. No manual auth handling needed.

Tools

a2a-discover.sh — List Agents & Providers

./a2a-discover.sh [--gateway-url URL] [--api-key KEY]

Lists registered A2A agents and all configured LLM providers with their models. Use provider slugs as --agent values when sending tasks.

Always discover before sending a task to confirm the target exists and is online.

# List all agents and providers (uses a2a.conf)
./a2a-discover.sh

# Override gateway URL
./a2a-discover.sh --gateway-url http://GATEWAY_LAN_IP:8090

a2a-send-task.sh — Send a Task

./a2a-send-task.sh --agent <slug> --message "task description" \
  [--model auto] [--target-agent <slug>] [--session-id <id>] \
  [--gateway-url URL] [--api-key KEY]

# Send a task with auto model selection
./a2a-send-task.sh --agent groq --message "Analyze the Q3 sales data"

# Specific model
./a2a-send-task.sh --agent mistral --message "Draft a blog post" --model mistral/mistral-small-latest

# Route to a specific A2A agent
./a2a-send-task.sh --agent ozore --message "Refactor the auth module" --target-agent coder

# Custom session ID
./a2a-send-task.sh --agent groq --message "Check logs" --session-id my-session-001

a2a-get-task.sh — Check Task Status

./a2a-get-task.sh --task-id <id> [--gateway-url URL] [--api-key KEY]

Retrieves the current status and any results of a previously sent task. Shows task metadata, model used, token usage, and the LLM response.

./a2a-get-task.sh --task-id 0566802a3e6931629df5a7baaba2d797

Typical Workflow

1. Configure → Create a2a.conf or set A2A_GATEWAY_URL env var
2. Discover → ./a2a-discover.sh to find available providers and models
3. Send → ./a2a-send-task.sh --agent <slug> --message "..." to delegate work
4. Poll → ./a2a-get-task.sh --task-id <id> to check progress (tasks often complete synchronously)
5. Retrieve → Same get-task call returns results when completed

Environment Variables