AgentIndex icon
AgentIndex
Handler logo
Handler
★ 46
vs
fast-agent logo
fast-agent
★ 3.9k

Handler vs fast-agent

Handler: Handler is an open-source A2A protocol client for your terminal. It provides a TUI and CLI to send messages, manage tasks, and inspect agent cards. An included MCP server lets AI assistants communicate with A2A agents.; fast-agent: fast-agent is a CLI-first framework for building and interacting with sophisticated multimodal AI agents and workflows. It offers comprehensive support for various LLM providers, structured outputs, and vision, with unique features like MCP Feature support and live streaming responses to the terminal.

01

TL;DR

Handler logo
HandlerDev Tooling · ★ 46

Interacting with A2A agents via an intuitive terminal UI

Read Handler full review →
fast-agent logo
fast-agentDev Tooling · ★ 3.9k

Rapid development and testing of sophisticated multimodal AI agents and workflows.

Read fast-agent full review →
02

Side-by-Side Comparison

Field
Handler logoHandler
fast-agent logofast-agent
Category
Dev Tooling
Dev Tooling
Stars
★ 46
★ 3.9k
License
GPL-3.0
Apache-2.0
Install Command
uv tool install a2a-handler
uv pip install fast-agent-mcp
Updated
3d ago
1d ago
Open Source
Yes
Yes
Website
↗ Visit
↗ Visit
GitHub
↗ GitHub
↗ GitHub
Tags
a2a, a2a-cli, a2a-client
acp, agent, agent-framework
03

Features

Handler logoHandler
01Terminal User Interface (TUI) for interactive use
02Command-line interface (CLI) for scripting
03Supports A2A protocol for agent communication
04Manage tasks and inspect agent cards
05Built-in MCP server for AI assistant integration
fast-agent logofast-agent
01Sophisticated multimodal Agent and Workflow creation.
02Comprehensive LLM provider support (e.g., Anthropic, OpenAI, Google, Ollama).
03Structured outputs, PDF, and Vision support.
04CLI-first with interactive terminal UI (TUI-style) and live streaming responses.
05Advanced agentic workflows like Chain, Parallel, MAKER, and Agents As Tools.
04

Use Cases

Handler logoHandler
↳Interacting with A2A agents via an intuitive terminal UI
↳Scripting agent communications in CI/CD pipelines
↳Enabling AI assistants to communicate with A2A agents via MCP
fast-agent logofast-agent
↳Rapid development and testing of sophisticated multimodal AI agents and workflows.
↳Diagnosing and tuning agent applications, including those requiring human input.
↳Implementing advanced agentic patterns for error reduction or complex task decomposition.
05

Best For

Handler logoHandler
—
fast-agent logofast-agent
Trending
FAQ

FAQ

What is the difference between Handler and fast-agent?
Both Handler and fast-agent are in the Dev Tooling category. Handler has 46 stars, while fast-agent has 3.9k stars.
Which is better, Handler or fast-agent?
The best choice depends on your use case. Choose Handler if Interacting with A2A agents via an intuitive terminal UI, and fast-agent if Rapid development and testing of sophisticated multimodal AI agents and workflows..
Is Handler free or open source?
Yes, Handler is open source on GitHub (GPL-3.0).
Is fast-agent free or open source?
Yes, fast-agent is open source on GitHub (Apache-2.0).
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Related

Alternatives to Handler →Alternatives to fast-agent →Handler details →fast-agent details →