> ## Documentation Index
> Fetch the complete documentation index at: https://docs.hasmcp.com/llms.txt
> Use this file to discover all available pages before exploring further.

# How does HasMCP pause the execution flow to prompt the user for authentication?

> Understanding the asynchronous architecture behind MCP execution states.

# Pausing Execution for Authentication

When an AI Agent is aggressively executing a complex multi-step reasoning loop (such as researching an entity across 5 different databases), a missing authentication error typically crashes the entire script, forcing the human to fix the token and manually restart the prompt.

HasMCP uniquely solves this by implementing native **Asynchronous Elicitation Pausing**.

### The Technical Mechanism

HasMCP utilizes bidirectional asynchronous SSE (Server-Sent Events) natively via MCP Streamable HTTP.

1. **State Preservation**: When HasMCP detects a missing Provider token, it actively suspends the specific tool execution thread horizontally in memory.
2. **Reverse Call**: HasMCP triggers a JSON-RPC callback down the open SSE connection. This explicitly instructs the client (e.g., Claude Desktop) to invoke its internal `auth_required` visual modal.
3. **Indefinite Hold**: The thread enters an asynchronous blocked state, preserving the exact LLM orchestrator loop natively.
4. **The Resume Payload**: Once the human finishes typing or authenticating via Google OAuth, the desktop client fires an internal `auth_complete` JSON payload back up the pipe.
5. **Reawakening**: The proxy intercepts this completion event, instantly validates the newly ingested token against the target API, and seamlessly reawakens the sleeping execution thread.

The LLM logic engine never crashes, never drops its current operational context, and gracefully finishes parsing exactly what the user initially requested.