Built-in MCP Tools Reference

LibrAgent includes a unified set of high-performance Rust-native Built-in MCP Servers, enabling code editing, file manipulation, web browsing, task planning, media processing, and background automation without needing external MCP server setup.

All built-in tools follow a consistent {server}__{tool} naming convention.

---

📌 Core Built-ins vs Optional Built-ins

LibrAgent built-in tools are categorized into Core tools (enabled by default on all sessions) and Optional tools (configurable per assistant).

1️⃣ Core Built-ins (Enabled by Default)

Essential tools automatically available for basic agent operations and UI interactions:

• workspace__*: File reading/writing/line-range editing, directory listing, terminal command execution
• ui__*: Interactive selection cards (select_prompt), text forms (text_prompt), data charts, circuit break pause (circuitBreak)
• agent__*: Autonomous sub-agent spawning and multi-agent orchestration
• skills__*: Skill execution and context loading
• playbook__*: Automation playbook listing, execution, and saving
• attachments__*: Session file attachment management and search
• scheduled_task__*: Background timers and recurring Cron task management
• scratchpad__*: Reasoning steps log and scratchpad calculation notes
• tool__*: Tool discovery and system tool management

2️⃣ Optional Built-ins (Configurable in Assistant Settings)

Domain-specific tools that can be enabled or disabled under Assistants → Edit → Tools:

• media__*: Image analysis, resizing, audio/image text extraction
• browser__*: Headless web browsing, DOM clicks, form typing, screenshot capture
• planning__*: Multi-step plan creation (create_plan), progress tracking, failure reflection (reflect)
• knowledge__*: Semantic memory storage and persistent knowledge retrieval
• setup-wizard__*: Python/Node/uv environment diagnostics and setup wizard
• history__*: Previous session history lookup

---

🛠️ Built-in Tools Detailed Reference

1. Workspace (workspace__* & runShell)

Tool Name	Description	Key Parameters
workspace__readFile	Read file content with line slicing	path, offset, size
workspace__writeFile	Create, overwrite, or append file	path, mode, content
workspace__strReplace	Exact string replacement in an existing file	path, old_string, new_string, replace_all
workspace__listDirectory	List directory contents	path, limit
workspace__runShell / runPowerShell	Execute shell command (supports background async)	command, timeout

2. Media (media__*) 🎨 (Optional)

Tool Name	Description	Key Parameters
media__seeContent	Inspect and analyze image/visual media	AbsolutePath
media__listenContent	Parse and analyze audio media	AbsolutePath
generate_image	AI image generation and visual mockups	Prompt, ImageName

3. Interactive UI (ask_question / ui__*)

Tool Name	Description
ask_question	Render interactive multi-choice selection modal
ui__wait	Pause execution for user input

4. Browser (browser__*) (Optional)

Tool Name	Description
navigateToUrl	Navigate to target web URL
clickElement	Click DOM element
inputText	Type text into web input
scrollPage	Scroll web page view
listInteractable	Extract clickable elements
evaluateJS	Execute custom JS snippet

5. Planning & Reflection (planning__*) (Optional)

Tool Name	Description
planning__createGoal	Establish multi-step goals for complex tasks
planning__updateGoal	Update step progress and goal status
planning__addTodo	Manage granular todo items
planning__reflect	Generate structured reflection on tool failures

6. Attachments & Scheduled Tasks (attachments__* / scheduled_task__*)

Tool Name	Description
attachments__readAttachment	Read session attachment contents
attachments__searchAttachments	Search through uploaded attachments
scheduled_task__create	Create one-shot timer or recurring Cron schedule
scheduled_task__list / delete	Manage active scheduled tasks

---

🧩 How to Add More Tools

When specialized capabilities beyond built-in tools are required (e.g. GitHub PR management, Slack messaging, ComfyUI image generation, arXiv paper search):

1. One-Click Presets (Recommended Extensions):
   • Go to Extensions → Tools → Recommended Extensions to add Brave Search, Exa, GitHub, Slack, arXiv, etc. (See Extensions Guide).
2. Add Custom MCP Server:
   • Register local npx/uvx processes or remote HTTP SSE servers. (See Custom MCP Guide).
3. Add Skills:
   • Install domain-specific workflow instructions as Skills. (See Skills Guide).