A2A-Ask

Talk to A2A agents from the command line.

A2A-Ask is a CLI client for the A2A (Agent-to-Agent) protocol. It enables you — or AI agents acting on your behalf — to discover remote agents, send messages, stream responses, handle multi-turn conversations, and manage task lifecycle.

Built with the official a2a-dotnet SDK and designed for both human users and AI agent skills (GitHub Copilot CLI, Claude Code, etc.).

Quick Start

# Install
dotnet tool install --global SpecWorks.A2A-Ask

# Discover an agent
a2a-ask discover https://agent.example.com --output text

# Send a message
a2a-ask send https://agent.example.com --message "Hello, what can you do?" --output text

# Stream a response in real-time
a2a-ask stream https://agent.example.com --message "Generate a report" --output text

Commands

Command Description
a2a-ask discover <url> Fetch and display an agent card
a2a-ask catalog list <target> List A2A agents available in a catalog
a2a-ask catalog show <target> Resolve one A2A agent from a catalog
a2a-ask catalog install <target> Install a catalog agent as a Copilot CLI custom agent
a2a-ask catalog uninstall <name> Remove an installed A2A Copilot bridge
a2a-ask catalog installed List installed A2A Copilot bridge agents
a2a-ask catalog sync [name] Refresh installed A2A Copilot bridges from agent cards
a2a-ask send <url> Send a message to an agent
a2a-ask stream <url> Stream a response or subscribe to task events
a2a-ask task get <url> Get current task status (for polling)
a2a-ask task list <url> List tasks on an agent
a2a-ask task cancel <url> Cancel a running task
a2a-ask auth login <url> Interactive OAuth2 authentication
a2a-ask auth logout <url> Clear stored authentication token
a2a-ask auth status <url> Check authentication status
a2a-ask auth register-client --client-id <id> --issuer <url> Persist an OAuth2 client registration
a2a-ask auth list-clients List persisted OAuth2 client registrations
a2a-ask auth remove-client --issuer <url> Remove a persisted OAuth2 client registration
a2a-ask version Display version info

Catalog Integration

A2A-Ask can browse AI catalogs and resolve A2A agents from catalog targets.

Target form Meaning
@agentName Bare catalog target. Phase 1 still requires an explicit catalog host or URL, so prefer @agentName@catalogAlias.
@agentName@catalogAlias Resolve one agent from a specific catalog host, origin, or catalog URL.
@@catalogAlias Browse a catalog by host, origin, or catalog URL. 
a2a-ask catalog list @@catalog.example.com
a2a-ask catalog show @weather@catalog.example.com
a2a-ask send @weather@catalog.example.com --message "Hello"

Use catalog list to browse catalog entries and catalog show to resolve one agent before sending. Plain URLs are sent directly for send, stream, and task commands without fetching an agent card first; use discover when you want card metadata. For older direct endpoints, add --a2a-version 0.3.

Authentication

A2A-Ask supports multiple authentication methods based on the agent's security requirements:

# Bearer token
a2a-ask send <url> --auth-token "eyJhbGciOi..." --message "Hello"

# API key
a2a-ask send <url> --api-key "sk-123" --api-key-header "X-API-Key" --message "Hello"

# Interactive OAuth2 (device code flow)
a2a-ask auth login <url>

# Persist a client registration for automatic issuer matching
a2a-ask auth register-client --client-id "my-cli-app" --issuer "https://login.microsoftonline.com/common/v2.0" --resource "https://graph.microsoft.com"

# Custom header
a2a-ask send <url> --auth-header "X-Custom=value" --message "Hello"

Multi-Turn Conversations

When an agent needs more information, it enters the InputRequired state. Continue the conversation using --task-id:

# First message
a2a-ask send <url> --message "Plan a trip to Japan" --output text
# → ⏸ InputRequired: "What dates are you considering?"

# Follow up with the same task
a2a-ask send <url> --task-id abc-123 --message "March 15-25" --output text

Streaming

For agents that support streaming, get real-time progress and artifact delivery:

a2a-ask stream <url> --message "Analyze this data" --output text
# 📤 Task started: abc-123 [Submitted]
# ⏳ [Working] Analyzing data...
# ⏳ [Working] Generating insights...
# ✅ [Completed]

Agent Skill

A2A-Ask includes a comprehensive SKILL.md for AI agent integration. Install it in your project to give AI assistants the ability to interact with any A2A agent:

# GitHub Copilot CLI
mkdir -p .github/skills/a2a-ask-cli
cp -r skill/SKILL.md .github/skills/a2a-ask-cli/

# Claude Code
mkdir -p .claude/skills/a2a-ask-cli
cp -r skill/SKILL.md .claude/skills/a2a-ask-cli/

Requirements

  • .NET 10.0 SDK or later
  • Works on Windows, macOS, and Linux

Building from Source

cd dotnet
dotnet build
dotnet run --project src/A2A-Ask -- --help

License

MIT — see LICENSE for details.

Additional Resources

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