> ## Documentation Index > Fetch the complete documentation index at: https://docs.bastani.ai/llms.txt > Use this file to discover all available pages before exploring further. # Extension examples > Runnable extension examples shipped with Atomic. # Extension examples ## Examples Reference All examples in [examples/extensions/](https://github.com/bastani-inc/atomic/tree/main/packages/coding-agent/examples/extensions). | Example | Description | Key APIs | | ------------------------------ | ------------------------------------------------------------------------------------------------------------------- | --------------------------------------------------------------------------------------------------------------------------------- | | **Tools** | | | | `hello.ts` | Minimal tool registration | `registerTool` | | `question.ts` | Width-wrapped single-question custom UI with option descriptions and typed answers | `registerTool`, `ui.custom` | | `questionnaire.ts` | Width-wrapped multi-step wizard with tab navigation and typed answers | `registerTool`, `ui.custom` | | `todo.ts` | Stateful tool with persistence | `registerTool`, `appendEntry`, `renderResult`, session events | | `dynamic-tools.ts` | Register tools after startup and during commands | `registerTool`, `session_start`, `registerCommand` | | `structured-output.ts` | Opt-in schema-specific `structured_output` tool using the canonical factory | `createStructuredOutputTool`, `registerTool`, terminating tool results | | `truncated-tool.ts` | Output truncation example | `registerTool`, `truncateHead` | | `tool-override.ts` | Override built-in read tool | `registerTool` (same name as built-in) | | **Commands** | | | | `pirate.ts` | Modify system prompt per-turn | `registerCommand`, `before_agent_start` | | `summarize.ts` | Conversation summary command | `registerCommand`, `ui.custom` | | `handoff.ts` | Cross-provider model handoff | `registerCommand`, `ui.editor`, `ui.custom` | | `qna.ts` | Q\&A with custom UI | `registerCommand`, `ui.custom`, `setEditorText` | | `send-user-message.ts` | Inject user messages | `registerCommand`, `sendUserMessage` | | `reload-runtime.ts` | Reload command and LLM tool handoff | `registerCommand`, `ctx.reload()`, `sendUserMessage` | | `shutdown-command.ts` | Graceful shutdown command | `registerCommand`, `shutdown()` | | **Events & Gates** | | | | `permission-gate.ts` | Block dangerous commands | `on("tool_call")`, `ui.confirm` | | `protected-paths.ts` | Block writes to specific paths | `on("tool_call")` | | `confirm-destructive.ts` | Confirm session changes | `on("session_before_switch")`, `on("session_before_fork")` | | `dirty-repo-guard.ts` | Warn on dirty git repo | `on("session_before_*")`, `exec` | | `input-transform.ts` | Transform user input | `on("input")` | | `input-transform-streaming.ts` | Streaming-aware input transform | `on("input")`, `streamingBehavior` | | `project-trust.ts` | Decide or defer project trust from a user/global or CLI extension | `on("project_trust")`, trust UI, required trust result | | `model-status.ts` | React to model changes | `on("model_select")`, `setStatus` | | `provider-payload.ts` | Inspect payloads and provider response headers | `on("before_provider_request")`, `on("after_provider_response")` | | `system-prompt-header.ts` | Display system prompt info | `on("agent_start")`, `getSystemPrompt` | | `claude-rules.ts` | Load rules from files | `on("session_start")`, `on("before_agent_start")` | | `prompt-customizer.ts` | Add context-aware tool guidance using `systemPromptOptions` | `on("before_agent_start")`, `BuildSystemPromptOptions` | | `file-trigger.ts` | File watcher triggers messages | `sendMessage` | | **Compaction & Sessions** | | | | `custom-compaction.ts` | Offline compacted-text override | `on("session_before_compact")` | | `trigger-compact.ts` | Trigger compaction manually | `compact()` | | `git-checkpoint.ts` | Git stash on turns | `on("turn_start")`, `on("session_before_fork")`, `exec` | | `auto-commit-on-exit.ts` | Commit on shutdown | `on("session_shutdown")`, `exec` | | **UI Components** | | | | `status-line.ts` | Footer status indicator | `setStatus`, session events | | `working-indicator.ts` | Customize the Working indicator used during prompt startup and active turns | `setWorkingIndicator`, `registerCommand` | | `github-issue-autocomplete.ts` | Add `#1234` issue completions on top of built-in autocomplete by preloading recent open issues from `gh issue list` | `addAutocompleteProvider`, `on("session_start")`, `exec` | | `custom-footer.ts` | Replace footer entirely | `registerCommand`, `setFooter` | | `custom-header.ts` | Replace startup header | `on("session_start")`, `setHeader` | | `modal-editor.ts` | Vim-style modal editor | `setEditorComponent`, `CustomEditor` | | `rainbow-editor.ts` | Custom editor styling | `setEditorComponent` | | `widget-placement.ts` | Widget above/below editor | `setWidget` | | `overlay-test.ts` | Overlay components | `ui.custom` with overlay options | | `overlay-qa-tests.ts` | Comprehensive overlay tests | `ui.custom`, all overlay options | | `notify.ts` | Simple notifications | `ui.notify` | | `timed-confirm.ts` | Dialogs with timeout | `ui.confirm` with timeout/signal | | `mac-system-theme.ts` | Auto-switch theme | `setTheme`, `exec` | | **Complex Extensions** | | | | `plan-mode/` | Full plan mode implementation | All event types, `registerCommand`, `registerShortcut`, `registerFlag`, `setStatus`, `setWidget`, `sendMessage`, `setActiveTools` | | `preset.ts` | Saveable presets (model, tools, thinking) | `registerCommand`, `registerShortcut`, `registerFlag`, `setModel`, `setActiveTools`, `setThinkingLevel`, `appendEntry` | | `tools.ts` | Toggle tools on/off UI | `registerCommand`, `setActiveTools`, `SettingsList`, session events | | **Remote & Sandbox** | | | | `ssh.ts` | SSH remote execution | `registerFlag`, `on("user_bash")`, `on("before_agent_start")`, tool operations | | `interactive-shell.ts` | Persistent shell session | `on("user_bash")` | | `sandbox/` | Sandboxed tool execution | Tool operations | | `gondolin/` | Route built-in tools and `!` commands into a Gondolin micro-VM | Tool operations, built-in tool overrides, `on("user_bash")` | | `subagent/` | Spawn sub-agents | `registerTool`, `exec` | | **Games** | | | | `snake.ts` | Snake game | `registerCommand`, `ui.custom`, keyboard handling | | `space-invaders.ts` | Space Invaders game | `registerCommand`, `ui.custom` | | `doom-overlay/` | Doom in overlay | `ui.custom` with overlay | | **Providers** | | | | `custom-provider-anthropic/` | Custom Anthropic proxy | `registerProvider` | | `custom-provider-gitlab-duo/` | GitLab Duo integration | `registerProvider` with OAuth | | **Messages & Communication** | | | | `message-renderer.ts` | Custom message rendering | `registerMessageRenderer`, `sendMessage` | | `event-bus.ts` | Inter-extension events | `pi.events` | | **Session Metadata** | | | | `session-name.ts` | Name sessions for selector | `setSessionName`, `getSessionName` | | `bookmark.ts` | Bookmark entries for /tree | `setLabel` | | **Misc** | | | | `inline-bash.ts` | Inline bash in tool calls | `on("tool_call")` | | `bash-spawn-hook.ts` | Adjust bash command, cwd, and env before execution | `createBashTool`, `spawnHook` | | `with-deps/` | Extension with npm dependencies | Package structure with `package.json` | ## Next steps Use the [Extension API reference](/extensions/api-reference) to check the context properties and method contracts used by these examples.