docs: MCP Server Instructions (#321)

pages/docs/configuration/librechat_yaml/object_structure/config.mdx

@@ -400,6 +400,7 @@ see: [Model Specs Object Structure](/docs/configuration/librechat_yaml/object_st
   - Additional configuration options include:
     - `timeout`: Timeout in milliseconds for MCP server requests. Determines how long to wait for a response for tool requests.
     - `initTimeout`: Timeout in milliseconds for MCP server initialization. Determines how long to wait for the server to initialize.
+    - `serverInstructions`: Controls whether server instructions are included in agent context. Can be `true` (use server-provided), `false` (disabled), or a custom string (overrides server-provided).
   - see: [MCP Servers Object Structure](/docs/configuration/librechat_yaml/object_structure/mcp_servers)
 
 **Example:**
@@ -411,6 +412,7 @@ mcpServers:
     url: http://localhost:3001/sse
     timeout: 30000
     initTimeout: 10000
+    serverInstructions: true  # Use server-provided instructions
   puppeteer:
     type: stdio
     command: npx
@@ -419,6 +421,7 @@ mcpServers:
       - "@modelcontextprotocol/server-puppeteer"
     timeout: 30000
     initTimeout: 10000
+    serverInstructions: "Do not access any local files or local/internal IP addresses"
   filesystem:
     # type: stdio
     command: npx

pages/docs/configuration/librechat_yaml/object_structure/mcp_servers.mdx

@@ -14,12 +14,14 @@ mcpServers:
     headers:
       X-User-ID: "{{LIBRECHAT_USER_ID}}"
       X-API-Key: "${SOME_API_KEY}"
+    serverInstructions: true  # Use server-provided instructions
   puppeteer:
     type: stdio
     command: npx
     args:
       - -y
       - "@modelcontextprotocol/server-puppeteer"
+    serverInstructions: "Do not access any local files or local/internal IP addresses"
   filesystem:
     # type: stdio
     command: npx
@@ -59,6 +61,7 @@ mcpServers:
     ['headers', 'Object', '(Optional, for `sse` and `streamable-http` types) Custom headers to send with the request. Supports dynamic user field substitution with `{{LIBRECHAT_USER_*}}` placeholders and environment variables with `${ENV_VAR}`.', 'headers:\n  X-User-ID: "{{LIBRECHAT_USER_ID}}"\n  X-API-Key: "${SOME_API_KEY}"'],
     ['iconPath', 'String', '(Optional) Defines the tool\'s display icon shown in the tool selection dialog.', 'iconPath: "/path/to/icon.svg"'],
     ['chatMenu', 'Boolean', '(Optional) When set to `false`, excludes the MCP server from the chatarea dropdown (MCPSelect) for quick and easy access. Defaults to `true`.', 'chatMenu: false'],
+    ['serverInstructions', 'Boolean or String', '(Optional) Controls how MCP server instructions are injected into agent context. Server instructions provide high-level usage guidance for the entire MCP server, complementing individual tool descriptions.', 'serverInstructions: true\n# or\nserverInstructions: "Custom instructions"'],
     ['timeout', 'Number', '(Optional) Timeout in milliseconds for MCP server requests. Determines how long to wait for a response for tool requests.', 'timeout: 30000'],
     ['initTimeout', 'Number', '(Optional) Timeout in milliseconds for MCP server initialization. Determines how long to wait for the server to initialize.', 'initTimeout: 10000'],
     ['env', 'Object', '(Optional, `stdio` type only) Environment variables to use when spawning the process.', 'env:\n  NODE_ENV: "production"'],
@@ -144,6 +147,34 @@ mcpServers:
 - **Description:** When set to `false`, excludes the MCP server from the chatarea dropdown (MCPSelect) for quick and easy access.
 - **Default Value:** `true` (The MCP server will be included in the chatarea dropdown)
 
+#### `serverInstructions`
+
+- **Type:** Boolean or String (Optional)
+- **Description:** Controls how MCP server instructions are injected into agent context. Server instructions provide high-level usage guidance for the entire MCP server, complementing individual tool descriptions.
+- **Options:**
+  - **`undefined`** (default): No instructions are included
+  - **`true`**: Use server-provided instructions (if available) - ideal for well-documented servers with comprehensive guidance
+  - **`false`**: Explicitly disable instructions - useful for saving context tokens or when tools are self-explanatory
+  - **`string`**: Use custom instructions (overrides server-provided) - best for application-specific workflows or when server instructions are insufficient
+- **Default Value:** `undefined` (no instructions included)
+- **Notes:**
+  - Instructions are automatically injected when `serverInstructions` is configured and the server's tools are available to the agent
+  - Multiple servers can each contribute instructions to the agent context
+- **Example:**
+  ```yaml
+  # Use server-provided instructions
+  serverInstructions: true
+  
+  # Use custom instructions
+  serverInstructions: |
+    When using this filesystem server:
+    1. Always use absolute paths for file operations
+    2. Check file permissions before attempting write operations
+  
+  # Explicitly disable instructions
+  serverInstructions: false
+  ```
+
 #### `env`
 
 - **Type:** Object (Optional, `stdio` type only)
@@ -255,6 +286,40 @@ filesystem:
   chatMenu: false  # Exclude from chatarea dropdown
 ```
 
+### MCP Server with Server Instructions
+
+```yaml filename="MCP Server with Instructions"
+# Server that uses its own provided instructions
+web-search:
+  type: streamable-http
+  url: https://example.com/mcp/search
+  serverInstructions: true
+
+# Server with instructions explicitly disabled
+filesystem:
+  command: npx
+  args:
+    - -y
+    - "@modelcontextprotocol/server-filesystem"
+    - /home/user/documents/
+  serverInstructions: false
+
+# Server with custom instructions
+puppeteer:
+  type: stdio
+  command: npx
+  args:
+    - -y
+    - "@modelcontextprotocol/server-puppeteer"
+  serverInstructions: |
+      Browser automation security and best practices:
+      1. Be cautious with local file access and internal IP addresses
+      2. Take screenshots to verify successful page interactions
+      3. Wait for page elements to load before interacting with them
+      4. Use specific CSS selectors for reliable element targeting
+      5. Check console logs for JavaScript errors when troubleshooting
+```
+
 ---
 
 **Importing MCP Server Configurations**
@@ -289,6 +354,11 @@ The `mcpServers` configurations allow LibreChat to dynamically interact with var
   - Boolean fields are converted to string representations ("true" or "false")
 - **Error Handling (`stderr`):**
   - Configuring `stderr` allows you to manage how error messages from the MCP server process are handled. The default `"inherit"` means that the errors will be printed to the parent process's `stderr`.
+- **Server Instructions:**
+  - Instructions are automatically injected into the agent's system message when MCP server tools are used
+  - Custom instructions (string values) take precedence over server-provided instructions
+  - Multiple MCP servers can each contribute their own instructions to the agent context
+  - Instructions are only included when the corresponding MCP server's tools are actually available to the agent
 
 ## References
 
@@ -298,4 +368,4 @@ The `mcpServers` configurations allow LibreChat to dynamically interact with var
 
 ---
 
-By properly configuring the `mcpServers` in your `librechat.yaml`, you can enhance LibreChat's functionality and integrate custom tools and services seamlessly.
+By properly configuring the `mcpServers` in your `librechat.yaml`, you can enhance LibreChat's functionality and integrate custom tools and services seamlessly.