Rename provider-nuances to provider-notes and add custom configuration docs

Add new Custom Configuration section documenting custom CLI arguments and
environment variables with screenshot. Rename navigation group to "Providers
& CLI" and reorder to list provider-notes first.

CONTRIBUTING.md

@@ -871,7 +871,7 @@ Pages are organized by topic in `docs.json` under `navigation.dropdowns`:
 | **Overview** | index, about/overview, features, screenshots | Introduction and feature highlights |
 | **Getting Started** | installation, getting-started | Onboarding new users |
 | **Usage** | general-usage, history, context-management, autorun-playbooks, git-worktrees, group-chat, remote-access, slash-commands, speckit-commands, configuration | Feature documentation |
-| **CLI & Providers** | cli, provider-nuances | Command line and agent-specific docs |
+| **Providers & CLI** | provider-notes, cli | Provider configuration and command line docs |
 | **Reference** | achievements, keyboard-shortcuts, troubleshooting | Quick reference guides |
 
 ### Adding a New Documentation Page

docs/docs.json

@@ -74,10 +74,10 @@
             ]
           },
           {
-            "group": "CLI & Providers",
+            "group": "Providers & CLI",
             "pages": [
-              "cli",
-              "provider-nuances"
+              "provider-notes",
+              "cli"
             ]
           },
           {

docs/provider-notes.md

@@ -1,11 +1,39 @@
 ---
-title: Provider Nuances
+title: Provider Notes
 description: Feature differences between Claude Code, Codex (OpenAI), and OpenCode providers.
 icon: puzzle
 ---
 
 Each AI provider has unique capabilities and limitations. Maestro adapts its UI based on what each provider supports.
 
+## Custom Configuration
+
+All providers support custom command-line arguments and environment variables. Configure these in **Settings → Providers** for each agent type.
+
+<Frame>
+  <img src="./screenshots/provider-config.png" alt="Provider configuration showing custom arguments and environment variables" />
+</Frame>
+
+### Custom Arguments
+
+Additional CLI arguments are appended to every call to the agent. Common use cases:
+
+- **Claude Code**: `--model claude-sonnet-4-20250514` to specify a particular model
+- **Codex**: `-m o3` to use a specific OpenAI model
+- **OpenCode**: `--model anthropic/claude-sonnet-4-20250514` to configure the model
+
+### Environment Variables
+
+Environment variables are passed to the agent process. Use these for:
+
+- API keys and authentication tokens
+- Configuration overrides (e.g., `CLAUDE_CONFIG_DIR` for isolated Claude configurations)
+- Provider-specific settings
+
+<Note>
+The `MAESTRO_SESSION_RESUMED` variable is automatically set to `1` when resuming sessions—you don't need to configure this manually.
+</Note>
+
 ## Claude Code
 
 | Feature | Support |
@@ -49,4 +77,5 @@ Each AI provider has unique capabilities and limitations. Maestro adapts its UI
 | Context operations | ✅ Merge, export, and transfer |
 | Thinking display | ✅ Streaming text chunks |
 
-**Note**: OpenCode uses the `run` subcommand which auto-approves all permissions (similar to Codex's YOLO mode). Maestro enables this via the `OPENCODE_CONFIG_CONTENT` environment variable.
+**Notes**:
+- OpenCode uses the `run` subcommand which auto-approves all permissions (similar to Codex's YOLO mode). Maestro enables this via the `OPENCODE_CONFIG_CONTENT` environment variable.