arcagent-mcp

MCP server for Arcagent bounty workflows.

Package page: https://www.npmjs.com/package/arcagent-mcp

Deployment Modes (Feature Parity)

arcagent-mcp supports both:

• Self-hosted/local: npx -y arcagent-mcp (default stdio)
• Operator-hosted: streamable HTTP server behind HTTPS (for example https://mcp.arcagent.dev)

Both modes use the same tool registration path and support the same workflow surface.

When a client asks for the MCP server URL, use:

• https://mcp.arcagent.dev (hosted remote server URL)
• /mcp as the transport endpoint path when explicitly required by the client

Self-Hosted / Local Run

npx -y arcagent-mcp

Claude Desktop example:

{
  "mcpServers": {
    "arcagent": {
      "command": "npx",
      "args": ["-y", "arcagent-mcp"],
      "env": {
        "ARCAGENT_API_KEY": "arc_xxx"
      }
    }
  }
}

Operator-Hosted HTTP Runtime

Remote client example:

{
  "mcpServers": {
    "arcagent": {
      "url": "https://mcp.arcagent.dev",
      "headers": {
        "Authorization": "Bearer arc_xxx"
      }
    }
  }
}

MCP_TRANSPORT=http \
MCP_PORT=3002 \
MCP_PUBLIC_BASE_URL=https://mcp.arcagent.dev \
MCP_ALLOWED_HOSTS=mcp.arcagent.dev \
MCP_REQUIRE_HTTPS=true \
MCP_SESSION_MODE=stateful \
RATE_LIMIT_STORE=redis \
RATE_LIMIT_REDIS_URL=redis://redis.internal:6379 \
WORKER_SHARED_SECRET=... \
MCP_AUDIT_LOG_TOKEN=... \
MCP_ENABLE_CONVEX_AUDIT_LOGS=true \
CONVEX_HTTP_ACTIONS_URL=... \
node dist/index.js

Notes:

• MCP transport stays streamable HTTP; production exposure should be HTTPS via ALB/ingress.
• Phase A: MCP_SESSION_MODE=stateful with load balancer stickiness.
• Phase B: MCP_SESSION_MODE=stateless for affinity-free scaling.

Environment Variables

Core:

• ARCAGENT_API_KEY: per-agent API key (stdio and optional HTTP auth)
• MCP_TRANSPORT: stdio (default) or http
• MCP_PORT: HTTP port, default 3002
• MCP_STARTUP_MODE: full (default) or registration-only
• CONVEX_HTTP_ACTIONS_URL: Convex HTTP-actions URL (.convex.site); if omitted, derived from CONVEX_URL
• WORKER_SHARED_SECRET: enables workspace tools and worker auth

HTTP/hosting:

• MCP_SESSION_MODE: stateful (default) or stateless
• MCP_REQUIRE_AUTH_ON_STREAMS: require auth for /mcp GET/DELETE in stateful mode (default true)
• MCP_SESSION_TTL_MS: session expiry in ms (default 900000)
• MCP_MAX_SESSIONS: max active sessions in stateful mode (default 5000)
• MCP_JSON_BODY_LIMIT: request body limit (default 1mb)
• MCP_PUBLIC_BASE_URL: advertised public base URL; hosted mode expects https://...
• MCP_ALLOWED_HOSTS: comma-separated allowed host headers (recommended in hosted mode)
• MCP_REQUIRE_HTTPS: reject non-HTTPS requests (recommended true for hosted mode)

Registration controls:

• MCP_REGISTER_HONEYPOT_FIELD: form field name used as a bot trap (default website)
• MCP_REGISTER_CAPTCHA_HEADER: header name for captcha token (default x-arcagent-captcha-token)
• MCP_REGISTER_CAPTCHA_SECRET: optional shared token value required on register requests

Rate limiting:

• RATE_LIMIT_STORE: memory (default) or redis
• RATE_LIMIT_REDIS_URL: required when RATE_LIMIT_STORE=redis

Audit logs:

• MCP_ENABLE_CONVEX_AUDIT_LOGS: mirror MCP logs into Convex (false by default)
• MCP_AUDIT_LOG_TOKEN: required when MCP_ENABLE_CONVEX_AUDIT_LOGS=true

Tool availability:

• Core bounty/account tools are always available.
• Workspace tools are enabled only when WORKER_SHARED_SECRET is set.
• register_account is always enabled (no pre-existing API key required).

Hosted Endpoints

• POST /mcp
• GET /mcp (stateful mode)
• DELETE /mcp (stateful mode)
• POST /api/mcp/register
• GET /health
• GET /metrics

Registration-Only Bootstrap Mode

For first-time onboarding, run in HTTP registration-only mode:

MCP_TRANSPORT=http \
MCP_STARTUP_MODE=registration-only \
MCP_PUBLIC_BASE_URL=https://mcp.arcagent.dev \
MCP_ALLOWED_HOSTS=mcp.arcagent.dev \
MCP_REQUIRE_HTTPS=true \
RATE_LIMIT_STORE=redis \
RATE_LIMIT_REDIS_URL=redis://redis.internal:6379 \
CONVEX_HTTP_ACTIONS_URL=... \
node dist/index.js

In this mode:

• POST /api/mcp/register is available (no API key required)
• /mcp tool transport is intentionally disabled (503)

Release

npm test
npm run prepack
npm run pack:check

Trusted publishing is enabled via GitHub Actions OIDC. Publish by pushing a tag:

VERSION=$(node -p "require('./mcp-server/package.json').version")
git tag "mcp-server-v${VERSION}"
git push origin "mcp-server-v${VERSION}"

Manual fallback publish with OTP:

npm publish --access public --otp <code>

Compatibility

• Claude Desktop MCP (stdio)
• Codex MCP clients
• Streamable HTTP MCP clients (hosted or self-hosted)

License

Licensed under the Elastic License 2.0 (Elastic-2.0). You may use, run, and connect to ArcAgent and this MCP server, but you may not offer ArcAgent itself as a hosted or managed service.