docs: Document context servers (#21170)

This PR adds documentation for context servers.

Release Notes:

- N/A

docs/src/assistant/assistant.md

@@ -15,3 +15,5 @@ This section covers various aspects of the Assistant:
 - [Using Commands](./commands.md): Explore slash commands that enhance the Assistant's capabilities and future extensibility.
 
 - [Prompting & Prompt Library](./prompting.md): Learn how to write and save prompts, how to use the Prompt Library, and how to edit prompt templates.
+
+- [Context Servers](./context-servers.md): Learn about context servers that enhance the Assistant's capabilities via the [Model Context Protocol](./model-context-protocol.md).

docs/src/assistant/context-servers.md

@@ -0,0 +1,49 @@
+# Context Servers
+
+Context servers are a mechanism for pulling context into the Assistant from an external source. They are powered by the [Model Context Protocol](./model-context-protocol.md).
+
+Currently Zed supports context servers providing [slash commands](./commands.md) for use in the Assistant.
+
+## Installation
+
+Context servers can be installed via [extensions](../extensions/context-servers.md).
+
+If you don't already have a context server, check out one of these:
+
+- [Postgres Context Server](https://github.com/zed-extensions/postgres-context-server)
+
+## Configuration
+
+Context servers may require some configuration in order to run or to change their behavior.
+
+You can configure each context server using the `context_servers` setting in your `settings.json`:
+
+```json
+{
+  "context_servers": {
+    "postgres-context-server": {
+      "settings": {
+        "database_url": "postgresql://postgres@localhost/my_database"
+      }
+    }
+}
+```
+
+If desired, you may also provide a custom command to execute a context server:
+
+```json
+{
+  "context_servers": {
+    "my-context-server": {
+      "command": {
+        "path": "/path/to/my-context-server",
+        "args": ["run"],
+        "env": {}
+      },
+      "settings": {
+        "enable_something": true
+      }
+    }
+  }
+}
+```

docs/src/assistant/model-context-protocol.md

@@ -0,0 +1,21 @@
+# Model Context Protocol
+
+Zed uses the [Model Context Protocol](https://modelcontextprotocol.io/) to interact with [context servers](./context-server.md):
+
+> The Model Context Protocol (MCP) is an open protocol that enables seamless integration between LLM applications and external data sources and tools. Whether you're building an AI-powered IDE, enhancing a chat interface, or creating custom AI workflows, MCP provides a standardized way to connect LLMs with the context they need.
+
+Check out the [Anthropic news post](https://www.anthropic.com/news/model-context-protocol) and the [Zed blog post](https://zed.dev/blog/mcp) for an introduction to MCP.
+
+## Try it out
+
+Want to try it for yourself?
+
+The following context servers are available today as Zed extensions:
+
+- [Postgres Context Server](https://github.com/zed-extensions/postgres-context-server)
+
+## Bring your own context server
+
+If there's an existing context server you'd like to bring to Zed, check out the [context server extension docs](../extensions/context-servers.md) for how to make it available as an extension.
+
+If you are interested in building your own context server, check out the [Model Context Protocol docs](https://modelcontextprotocol.io/introduction#get-started-with-mcp) to get started.