Clarify authentication requirement in README

Expand the auth note to explain that users must authenticate themselves
with agents and that all agents are verified via CI.

Author: ignatov

README.md

@@ -4,12 +4,16 @@
 
 A registry of agents and extensions implementing the [Agent Client Protocol, ACP](https://github.com/agentclientprotocol/agent-client-protocol).
 
-> **Note**: This registry only includes agents that support [authentication](AUTHENTICATION.md). Agents must implement auth flows to be listed here. See also the [ACP auth methods proposal](https://github.com/agentclientprotocol/agent-client-protocol/blob/main/docs/rfds/auth-methods.mdx).
+> **Authentication Required**: This registry maintains a curated list of **agents that support user authentication**. 
+> 
+> Users must be able to authenticate themselves with agents to use them. 
+> All agents are verified via CI to ensure they return valid `authMethods` in the ACP handshake. 
+> See [AUTHENTICATION.md](AUTHENTICATION.md) for implementation details and the [ACP auth methods proposal](https://github.com/agentclientprotocol/agent-client-protocol/blob/main/docs/rfds/auth-methods.mdx) for the specification.
 
 ## Included Agents
 
 | Agent                                                                       | Description                                                                       |
-| --------------------------------------------------------------------------- | --------------------------------------------------------------------------------- |
+|-----------------------------------------------------------------------------|-----------------------------------------------------------------------------------|
 | [Auggie CLI](https://github.com/augmentcode/auggie-zed-extension)           | Augment Code's powerful software agent, backed by industry-leading context engine |
 | [Claude Code](https://github.com/zed-industries/claude-code-acp)            | ACP adapter for Claude Code                                                       |
 | [Codex CLI](https://github.com/zed-industries/codex-acp)                    | ACP adapter for OpenAI's coding assistant                                         |