Synthflow

Synthflow plugin

Connects Claude to the Synthflow AI voice-agent platform, and ships the review skills Claude uses on top of it.

Once connected, Claude can call Synthflow tools directly — managing assistants, phone numbers, calls, knowledge bases, actions, and simulations from your editor.

Which connection to use

There are two ways to get the Synthflow tools, and you want one of them:

Your setup	Use
claude.ai, Claude Desktop, Claude Cowork	The official Synthflow connector — it handles region selection during sign-in
Claude Code, interactive	Either. The connector if you already have it; otherwise this plugin's bundled server
Claude Code headless, CI, cron	This plugin's bundled server with an API key (see Alternative: API key)

If you use the connector, keep this plugin installed anyway — the skills below work against either connection.

Skills

Skill	What it does
call-review	Audits the last 100 calls for an agent against a problem checklist (unresolved outcomes, repetition, dropout, compliance risks) and reports flagged calls with evidence.
prompt-review	Reviews a voice-agent prompt before deployment: contradictions, missing context, tool/action alignment, escalation gaps, compliance risk, and regression risk.

Claude invokes these automatically when the task fits; you can also run them explicitly, e.g. /synthflow:call-review.

Regions

Synthflow runs three regional MCP endpoints, and the endpoint must match your workspace's region — a mismatch (e.g. the EU URL with a US workspace) stops the connection from working. Find your region under Admin → Workspace Settings → Preferences → Customer Region.

With the official connector, this is handled for you — region selection happens during sign-in, so there's nothing to configure.

The rest of this section applies only to the plugin's bundled server and to servers you add by hand:

Region	MCP URL
Global	https://mcp.synthflow.ai/mcp
United States	https://mcp.us.synthflow.ai/mcp
European Union	https://mcp.eu.synthflow.ai/mcp

The bundled server uses the Global endpoint. For a US or EU workspace, either use the official connector, or add the server with your region's URL:

claude mcp add --transport http synthflow https://mcp.eu.synthflow.ai/mcp

Then authenticate via /mcp as usual. You can keep the plugin enabled for its skills — its Global server will simply show as unauthenticated, which is safe to ignore.

Setup

Either path authenticates with OAuth — you sign in through Synthflow and select a workspace, so there is no API key to copy or manage by hand.

Official connector

Enable the Synthflow connector from Claude's connector directory and sign in, picking your region and workspace when prompted. Nothing else to configure — this is the recommended path on claude.ai, Desktop, and Cowork, and fine in interactive Claude Code.

Plugin's bundled server

1. Install and enable the plugin (Global-region workspaces work out of the box; US/EU, see Regions).
2. Run /mcp, select the synthflow server, and choose Authenticate. A browser window opens to Synthflow's sign-in, where you pick the workspace and click Allow access.
3. /mcp should now show the server as connected, with its tools listed.

Alternative: API key (headless / CI)

Environments without a browser can connect with a Synthflow API key instead (generate one in Admin → Workspace Settings → API Keys):

claude mcp add --transport http synthflow https://mcp.synthflow.ai/mcp \
  --header "Authorization: Bearer $SYNTHFLOW_API_KEY"

Substitute your region's URL from the table above. Claude Code deduplicates locally configured servers by URL, so this and the plugin's bundled server won't produce duplicate tools.

How it works

The plugin ships two remote MCP server definitions (.mcp.json):

{
  "mcpServers": {
    "synthflow": {
      "type": "http",
      "url": "https://mcp.synthflow.ai/mcp"
    },
    "synthflow-docs": {
      "type": "http",
      "url": "https://docs.synthflow.ai/_mcp/server"
    }
  }
}

• synthflow — the workspace server (Global endpoint — see Regions for US/EU workspaces). Claude Code detects that the server requires OAuth and handles the sign-in flow via /mcp. Tools added to the hosted server appear automatically — no plugin update required. The URL is deliberately static: config placeholders like ${user_config.*} only resolve inside Claude Code and break the connector on other Claude surfaces. Skip this one if you're using the official connector.
• synthflow-docs — searches the official docs at docs.synthflow.ai via a searchDocs tool. The workspace server and the official connector both expose an equivalent search_docs, so this exists for one reason: it needs no sign-in, letting Claude look up Synthflow features and setup steps before you've authenticated anything.

Troubleshooting

• Server not listed in /mcp — make sure the plugin is enabled (/plugin), then run /reload-plugins.
• Connection or sign-in fails outright — check for a region mismatch: the configured MCP URL must match your workspace's Customer Region (see Regions).
• 401 Unauthorized after previously working — the OAuth token expired and refresh failed. Open /mcp, select the server, and choose Re-authenticate.
• API-key connection returns Unauthorized — the key is unset, wrong, or expired in the shell that launched Claude Code. Confirm with echo $SYNTHFLOW_API_KEY, then regenerate it in Workspace Settings if needed.
• Wrong workspace data — you selected a different workspace during sign-in, or you're on a subaccount. Re-authenticate and pick the right workspace.

Reference

• Synthflow connector for Claude & Claude Code: https://docs.synthflow.ai/anthropic
• Synthflow MCP server (API-key clients): https://docs.synthflow.ai/mcp-server