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dev.agentsim/mcp

Official registry Security

Control plane for agent auth walls. Connector 0 handles SMS OTP with US test numbers.

Source code Documentation

Install

Add this to your client's MCP configuration (Claude Desktop: claude_desktop_config.json; Cursor: .cursor/mcp.json; VS Code and others use the same "mcpServers" shape).

Remote (streamable-http)
Claude Code 
claude mcp add --transport http dev-agentsim-mcp 'https://mcp.agentsim.dev/mcp'
JSON configuration (Claude Desktop, Cursor, VS Code) 
{
    "mcpServers": {
        "dev-agentsim-mcp": {
            "type": "http",
            "url": "https://mcp.agentsim.dev/mcp"
        }
    }
}

Documentation

From the project's README on GitHub, refreshed weekly. Links open on GitHub.

Contents
  1. agentsim-mcp
  2. Setup
  3. Tools
  4. Auth
  5. Supported Countries

agentsim-mcp

Availability: Live SMS is self-serve for owned public HTTPS services after exact-origin verification and an allow policy. Hobby includes 10 live US SMS sessions per UTC month, with one active live session per account and no card required. Builder is $99/month and includes 50 live US SMS sessions. Checkout shows tax and renewal terms before payment, and existing agreements keep their terms. Check current access and channel support before using live examples.

MCP server that exposes AgentSIM challenge tools to AI coding assistants: Codex CLI, Claude Code, Cursor, Windsurf, and any other MCP-compatible host. Primary tools: open_challenge, wait_for_verdict. Aliases: provision_number, wait_for_otp.

Setup

For Codex CLI, follow Connect Codex. It covers key handling, the SMS wait timeout, and browser access. Then use the complete phone sign-in prompt.

Claude Code
claude mcp add agentsim -e AGENTSIM_API_KEY=asm_live_xxx -- uvx agentsim-mcp
Claude Desktop

Add to ~/Library/Application Support/Claude/claude_desktop_config.json:

{
  "mcpServers": {
    "agentsim": {
      "command": "uvx",
      "args": ["agentsim-mcp"],
      "env": {
        "AGENTSIM_API_KEY": "asm_live_xxx"
      }
    }
  }
}
Cursor / Windsurf

Add agentsim-mcp as a stdio MCP server with AGENTSIM_API_KEY in the environment config.

Remote (no install)

Connect directly to the hosted MCP server without installing anything locally:

{
  "mcpServers": {
    "agentsim": {
      "type": "streamable-http",
      "url": "https://mcp.agentsim.dev/mcp",
      "headers": {
        "x-api-key": "asm_live_..."
      }
    }
  }
}

The hosted endpoint uses stateless HTTP and does not issue mcp-session-id headers. The session_id returned by AgentSIM tools identifies a challenge and remains valid across tool calls.

Tools

ToolDescription
identify_agentAdd a stable agent ID to the console without opening a challenge, sending SMS, or using allowance
open_challengeOpen an authentication challenge session for a required owned service_url; accepts channel (sms_otp \email_otp \magic_link \webauthn_required), returns session ID + identifier
wait_for_verdictLong-poll for the challenge verdict — returns structured outcome including otp_code, magic_link, or webauthn_required; policy denial fails on open
get_messagesRead SMS metadata and parsed codes; reading codes consumes them
release_numberRelease a session early (allocation returned to pool)
list_numbersList all active sessions for this account
Legacy Aliases (Backward Compatibility)
ToolMaps toDescription
provision_numberopen_challenge(channel=sms_otp)Provision a temporary programmable US number for SMS OTP — kept for backward compatibility
wait_for_otpwait_for_verdictLegacy wait with automatic extension after timeout by default; number may be unchanged

Auth

For stdio, set AGENTSIM_API_KEY in the process environment. For hosted HTTP, every request must send its own x-api-key; the server validates and forwards that caller-scoped key. Get a key at console.agentsim.dev.

Supported Countries

US

Frequently asked questions

What is dev.agentsim/mcp?

Control plane for agent auth walls. Connector 0 handles SMS OTP with US test numbers.

How do I install dev.agentsim/mcp?

It runs as a remote server. In Claude Code: claude mcp add --transport http dev-agentsim-mcp 'https://mcp.agentsim.dev/mcp'. For other clients, paste the JSON configuration from this page into their MCP settings.

Does dev.agentsim/mcp need an API key?

Its registry entry lists no required key or secret. Some features may still need an account with the service it connects to.

Is dev.agentsim/mcp open source?

Yes. Its code is on GitHub under the MIT license.

Who maintains dev.agentsim/mcp?

It is published by agentsimdev. AI.tn lists it but does not maintain or endorse it.

From the official MCP Registry. Listing is not an endorsement: review a server's code and permissions before giving it access to your data.