docs: update Learning Hub with CLI v1.0.32-v1.0.34 features

- Add auto model selection to Model Picker section
- Document file attachment feature for prompts
- Add new slash command aliases (/bug, /continue, /release-notes, /export, /reset, /upgrade)
- Document slash command suggestion for misspelled commands
- Add usage limit warnings (50% and 95% thresholds)
- Document session idle timeout (--session-idle-timeout)
- Add --print-debug-info flag documentation
- Document --connect flag for remote sessions
- Document short session ID prefixes for --resume
- Add COPILOT_AGENT_SESSION_ID env var to MCP docs
- Note sub-agents inherit session model in auto mode
- Add j/k vim navigation and x to terminate in tasks dialog
- Update lastUpdated dates for modified files

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

website/src/content/docs/learning-hub/agents-and-subagents.md

@@ -3,7 +3,7 @@ title: 'Agents and Subagents'
 description: 'Learn how delegated subagents differ from primary agents, when to use them, and how to launch them in VS Code and Copilot CLI.'
 authors:
   - GitHub Copilot Learning Hub Team
-lastUpdated: 2026-04-02
+lastUpdated: 2026-04-20
 estimatedReadingTime: '9 minutes'
 tags:
   - agents
@@ -44,7 +44,7 @@ Subagents are useful because they are not just "the same agent in another tab."
 - **Focused instructions**: the subagent can use a tighter role, such as planner, implementer, reviewer, or researcher.
 - **Parallelism**: multiple subagents can work at the same time when tasks do not conflict.
 - **Controlled synthesis**: the parent agent decides what gets brought back into the main conversation.
-- **Alternative model selection**: the subagent can use a different AI model to perform a task, so while our main agent might be using a generalist model, a subagent could be configured to use a more specialized one for code review or research.
+- **Alternative model selection**: the subagent can use a different AI model to perform a task, so while our main agent might be using a generalist model, a subagent could be configured to use a more specialized one for code review or research. When the session model is set to `auto`, sub-agents automatically inherit the session model — Copilot picks the best model for each subagent's task without requiring explicit configuration.
 
 That isolation is one of the main reasons subagents can outperform a single monolithic agent on larger tasks.
 

website/src/content/docs/learning-hub/copilot-configuration-basics.md

@@ -3,7 +3,7 @@ title: 'Copilot Configuration Basics'
 description: 'Learn how to configure GitHub Copilot at user, workspace, and repository levels to optimize your AI-assisted development experience.'
 authors:
   - GitHub Copilot Learning Hub Team
-lastUpdated: 2026-04-16
+lastUpdated: 2026-04-20
 estimatedReadingTime: '10 minutes'
 tags:
   - configuration
@@ -405,6 +405,8 @@ These files follow the same format as `config.json` and are loaded after the glo
 
 The model picker opens in a **full-screen view** with inline reasoning effort adjustment. Use the **← / →** arrow keys to change the reasoning effort level (`low`, `medium`, `high`) directly from the picker without leaving the session. The current reasoning effort level is also displayed in the model header (e.g., `claude-sonnet-4.6 (high)`) so you always know which level is active.
 
+**Auto model selection**: Select `auto` as your model to let Copilot automatically pick the best available model for each session based on task complexity and availability. This is useful when you want Copilot to optimise performance without having to manually switch models. Sub-agents launched in auto mode also inherit the session model automatically.
+
 ### CLI Session Commands
 
 GitHub Copilot CLI has two commands for managing session state, with distinct behaviours:
@@ -471,7 +473,36 @@ The `/env` command shows all loaded environment details — instructions, MCP se
 /env
 ```
 
-The `/statusline` command (with `/footer` as an alias) lets you control which items appear in the terminal status bar. You can show or hide individual indicators like the working directory, current branch, effort level, context window usage, and quota:
+**Slash command aliases**: Several commands now have convenient aliases for common workflows:
+
+| Alias | Maps to | Purpose |
+|-------|---------|---------|
+| `/continue` | `/resume` | Resume a backgrounded session |
+| `/bug` | Built-in bug reporter | Report a bug with context |
+| `/release-notes` | Built-in changelog | View recent release notes |
+| `/export` | Built-in exporter | Export session content |
+| `/reset` | `/clear` | Start a fresh session |
+| `/upgrade` | `/update` | Update the CLI to the latest version |
+
+**Slash command suggestions**: When you type an unrecognized or misspelled slash command, the command picker automatically suggests similar commands so you can correct typos without memorizing exact names.
+
+**Attaching files to prompts**: You can attach supported document files (PDFs, text files, images, etc.) to your prompts for the agent to read and reason about. This is useful for providing reference documentation, design specs, or any external context that isn't already in your codebase.
+
+**Usage limit warnings**: Copilot CLI shows warnings when you reach **50%** and **95%** of your weekly usage quota, giving you advance notice before hitting rate limits.
+
+**Session idle timeout**: By default, sessions do not time out due to inactivity. If you want sessions to end automatically after a period of inactivity, configure the timeout with the `--session-idle-timeout` flag:
+
+```bash
+copilot --session-idle-timeout 30m   # end session after 30 minutes of inactivity
+```
+
+**Debugging and diagnostics**: Use the `--print-debug-info` flag to display version information, terminal capabilities, and relevant environment variables — helpful when troubleshooting unexpected CLI behaviour:
+
+```bash
+copilot --print-debug-info
+```
+
+ (with `/footer` as an alias) lets you control which items appear in the terminal status bar. You can show or hide individual indicators like the working directory, current branch, effort level, context window usage, and quota:
 
 ```
 /statusline             # show the statusline configuration menu
@@ -507,6 +538,22 @@ copilot --plan          # start in plan mode (propose without executing)
 
 This is useful in scripts or CI pipelines where you want the CLI to immediately begin working in a specific mode without an interactive prompt.
 
+**Resuming and connecting to sessions**: The `--resume` flag (and its alias `--continue`) accepts short session ID prefixes (7 or more hex characters) in addition to full session IDs, making it faster to resume a session from the command line:
+
+```bash
+copilot --resume a1b2c3d    # resume session whose ID starts with a1b2c3d
+```
+
+When resuming a remote session, the `--remote` flag is inherited automatically — you don't need to re-specify it each time.
+
+The `--connect` flag lets you connect directly to an existing remote session by its full ID without going through the session picker:
+
+```bash
+copilot --connect <session-id>
+```
+
+**Keyboard shortcuts in the tasks dialog**: Use **j/k** for vim-style navigation through tasks and **x** to kill a running task from within the tasks dialog.
+
 ## Common Questions
 
 **Q: How do I disable Copilot for specific files?**

website/src/content/docs/learning-hub/understanding-mcp-servers.md

@@ -117,6 +117,8 @@ This guided flow is the recommended way to add new MCP servers, especially for s
 
 **env**: Environment variables passed to the server process. Use these for connection strings, API keys, and configuration—never hardcode secrets in the JSON file.
 
+In addition to the `env` field, Copilot CLI automatically injects the **`COPILOT_AGENT_SESSION_ID`** environment variable into all shell commands and MCP server processes. This lets MCP servers identify the current Copilot session if they need to correlate activity or pass session context to external systems.
+
 **type** (remote servers): The transport type for remote MCP servers (`http` or `sse`). This field can now be omitted — the CLI defaults to `http` when no type is specified, simplifying remote server configuration.
 
 ### Managing Persistent MCP Configuration via Server RPCs