Add external agents page + creating new threads section

docs/src/SUMMARY.md

@@ -47,7 +47,7 @@
 - [Overview](./ai/overview.md)
 - [Agent Panel](./ai/agent-panel.md)
   - [Tools](./ai/tools.md)
-  - [Gemini CLI](./ai/gemini-cli.md)
+  - [External Agents](./ai/external-agents.md)
 - [Inline Assistant](./ai/inline-assistant.md)
 - [Edit Prediction](./ai/edit-prediction.md)
 - [Text Threads](./ai/text-threads.md)

docs/src/ai/agent-panel.md

@@ -19,7 +19,15 @@ If you need extra room to type, you can expand the message editor with {#kb agen
 You should start to see the responses stream in with indications of [which tools](./tools.md) the model is using to fulfill your prompt.
 
 > Note that, currently, not all features outlined below work for external agents, like Gemini CLI.
-> Features like checkpoints, token usage display, and model selection may be supported in the future for them.
+> Features like _checkpoints_, _token usage display_, and _model selection_ may be supported in the future for them.
+
+### Creating New Threads
+
+The default view for the Agent Panel uses Zed's first-party agent.
+Every time that you hit {#kb agent::NewThread}, it creates a new thread using the currently selected agent and view.
+
+To change that, go to the plus button in the top-right of the Agent Panel and choose another option.
+You'll see the option to create a new [Text Thread](./text-threads.md) or, if you have [external agents](/.external-agents.md) connected, to chose new threads with them.
 
 ### Editing Messages {#editing-messages}
 

docs/src/ai/external-agents.md

@@ -1,16 +1,24 @@
-# Gemini CLI
+# External Agents
 
-Zed provides the ability to run [Gemini CLI](https://github.com/google-gemini/gemini-cli) directly in the [Agent Panel](./agent-panel.md).
+Through the Agent Client Protocol (ACP), Zed can expose external agents that run as a subprocess.
+
+Read the ACP documentation to learn how to add your agent to Zed.
+
+At the moment, Zed supports [Gemini CLI](https://github.com/google-gemini/gemini-cli) as a reference implementation of an external agent speaking ACP.
+
+## Gemini CLI
+
+Zed provides the ability to run [Gemini CLI](https://github.com/google-gemini/gemini-cli) directly in the [agent panel](./agent-panel.md).
 
 Under the hood we run Gemini CLI in the background, and talk to it over the [Agent Client Protocol (ACP)](https://agentclientprotocol.com).
 This means that you're running the real Gemini CLI, with all of the advantages of that, but you can see and interact with files in your editor.
 
-## Getting Started
+### Getting Started
 
 The Gemini integration should be enabled by default.
 To access it, run `agent: new gemini cli thread`.
 
-### Installation
+#### Installation
 
 If you don't yet have Gemini CLI installed, then Zed will install a version for you.
 If you do, then we will use the version of Gemini CLI on your path.
@@ -18,7 +26,7 @@ If you do, then we will use the version of Gemini CLI on your path.
 If the version you haven installed is too old, you will see an error message, and you will have to upgrade Gemini CLI.
 The instructions depend on how you originally installed it, but typically, running `npm install -g gemini-cli@preview` should work to fix it.
 
-### Authentication
+#### Authentication
 
 After you have Gemini CLI running, you'll be prompted to choose your authentication method.
 Most users should click the "Log in with Google" button that will show up in the UI, but if you have an API key already you can also click "Use Gemini API Key".
@@ -27,7 +35,7 @@ The "Vertex AI" option is for those who are using Vertex AI, and have already co
 
 For more information, see the [Gemini CLI docs](https://github.com/google-gemini/gemini-cli/blob/main/docs/index.md).
 
-## Usage
+### Usage
 
 Similar to the built-in agent in [the agent panel](./agent-panel.md), you can use Gemini CLI to do anything that you need.
 You can @-mention files, recent conversations, symbols, or fetch the web.

docs/src/ai/overview.md

@@ -6,6 +6,8 @@ Learn how to get started using AI with Zed and all its capabilities.
 
 - [Configuration](./configuration.md): Learn how to set up different language model providers like Anthropic, OpenAI, Ollama, Google AI, and more.
 
+- [External Agents](./external-agents.md): Learn how to plug in your favorite agent into Zed.
+
 - [Subscription](./subscription.md): Learn about Zed's hosted model service and other billing-related information.
 
 - [Privacy and Security](./privacy-and-security.md): Understand how Zed handles privacy and security with AI features.