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+# Product Requirements Document (PRD)
+
+## Overview
+
+nanobot is an ultra-lightweight personal AI assistant framework. It provides a chat-controlled bot that can execute tasks through natural language commands, with pluggable "channels" for different messaging platforms.
+
+## Target Audience
+
+- Individual developers and power users who want a personal AI assistant
+- Users who prefer self-hosted, privacy-respecting AI tools
+- Teams using Mattermost who want an integrated AI assistant
+- Users who need AI assistance with file operations, shell commands, and web searches
+
+## Core Features
+
+### 1. Agent Loop
+- Conversational AI powered by LLMs (Anthropic, OpenAI, Google, OpenRouter, Ollama)
+- Tool execution with iterative refinement
+- Session management with persistent conversation history
+- Memory consolidation to manage context window limits
+
+### 2. Tool System
+- **Filesystem**: read, write, edit, list files
+- **Shell**: execute arbitrary commands with configurable security constraints
+- **Web**: search (Brave), fetch and parse URLs
+- **Message**: send intermediate updates to chat channels
+- **Spawn**: delegate long-running tasks to background subagents
+- **Cron**: schedule recurring tasks
+
+### 3. Channel System
+- **Mattermost**: WebSocket-based real-time messaging with REST API for posts
+- **CLI**: local interactive terminal or single-shot mode
+- Extensible channel interface for future platforms
+
+### 4. Scheduling
+- **Cron Service**: schedule tasks with cron expressions, intervals, or one-time execution
+- **Heartbeat**: periodic wake-up to check for tasks (e.g., HEARTBEAT.md)
+
+### 5. Memory & Skills
+- Long-term memory with consolidation
+- Skill loading from workspace
+- System prompt construction from templates (SOUL.md, USER.md, TOOLS.md)
+
+## Non-Goals (Out of Scope)
+
+- Non-Mattermost channels (Telegram, Discord, Slack, etc.)
+- MCP (Model Context Protocol) client support
+- Extended thinking/reasoning token handling
+- Onboard configuration wizard
+- Multi-tenancy or user authentication
+
+## User Stories
+
+1. As a developer, I want to ask the AI to read and modify files in my workspace so I can work faster.
+2. As a team lead, I want the bot to respond in Mattermost channels when mentioned so my team can get AI help without leaving chat.
+3. As a power user, I want to schedule recurring tasks so the AI can check things automatically.
+4. As a privacy-conscious user, I want to run the bot locally with Ollama so my data stays on my machine.
+
+## Success Metrics
+
+- Zero external dependencies for core functionality beyond LLM providers
+- Sub-second response time for tool execution
+- Graceful degradation on LLM errors
+- Clear error messages for configuration issues