REST

ElevenLabs integration

In brief

Recommended path today: Server Tool (webhook) → REST. Remote MCP does not yet support Streamable HTTP/SSE required by ElevenLabs.

Prerequisites

  • ElevenLabs account with Agents
  • AskMarcel API key (ak_live_)
  • Voice agent configured in ElevenLabs

Why REST and not MCP?

ElevenLabs requires an MCP server with SSE or Streamable HTTP. Our MCP endpoint returns 405 on GET + Accept: text/event-stream. Webhook tool → REST is guaranteed and tested.

MCP in preparation

Streamable HTTP support is planned. This page will be updated when SSE transport ships.

Configure a Server Tool

  1. 1

    Open your ElevenLabs agent

    Agents → your agent → Tools → Add tool → Webhook.

  2. 2

    URL and method

    POST https://api.askmarcel.app/v1/diagnostic

  3. 3

    Headers

    Authorization: Bearer YOUR_AK_LIVE_KEY and Content-Type: application/json.

  4. 4

    Parameters

    Define brand (string), model (string), error_code (string) as parameters the agent can extract from conversation.

    Body template
    {
      "brand": "{{brand}}",
      "model": "{{model}}",
      "error_code": "{{error_code}}"
    }
  5. 5

    System prompt

    Instruct the agent to always cite the source (manual, page) returned by the API before giving a procedure.

Handle the response

Map steps[] for voice readout and source.page for traceability. confidence.level = low → ask technician for confirmation.

Verify it works

Test the agent with "I have error E7 on a Mitsubishi Ecodan". The agent should call the tool and read the steps.

curl test
curl -s https://api.askmarcel.app/v1/diagnostic \
  -H "Authorization: Bearer ak_live_..." \
  -H "Content-Type: application/json" \
  -d '{"brand":"Mitsubishi","model":"Ecodan PUHZ-W85","error_code":"E7"}'

Known limitations

  • Native ElevenLabs MCP not supported today (no SSE)
  • Voice latency: plan a hold message during API call (~200-500ms warm)
  • Developer tier not allowed in production

Video coming soon

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