What is an MCP server for HVAC?

The Model Context Protocol lets Claude Desktop, ChatGPT or your AI agent call AskMarcel tools directly — error-code lookup, procedures, diagnostic sessions — without any HTTP development. You plug in the server URL and your agent gets manufacturer knowledge.

Does the API cover my brand's error codes?

The corpus covers 126 brands and 400,000+ manufacturer-sourced error codes. The coverage route tells you, model by model, whether an exact manual is available — before any call is ever billed.

Can we plug AskMarcel into our CMMS or field-service tool?

Yes. The REST API integrates with any tool that makes HTTP calls: CMMS, field service, CRM, customer support. Integration support on your stack is included.

What happens when AskMarcel doesn't know?

The API abstains instead of inventing: no_exact_source status, null diagnostic — and the call is not billed. A raw LLM hallucinates; Marcel cites the manual or stays silent.

Do you also equip our competitors?

Yes — by design. AskMarcel is a neutral data layer, the way a water supplier doesn't take sides among its customers. Your differentiation stays in your service, your prompt and your customer relationship.

How is our data protected?

Requests transit over HTTPS. We do not store the content of your customer conversations. The API returns a sourced answer; your stack keeps control of logs and retention.

Can we test before committing to integration?

Yes: the Developer tier is free up to 50 requests/month, self-serve. Ideal for a technical POC before moving to assisted integration.

AskMarcel400,000+ error codes

Book a demo Log in

MARCEL INSIDE · REST API & MCP

AI ASSISTANT FOR HVAC AFTER-SALES TEAMS

MANUFACTURER KNOWLEDGE.
INSIDE YOUR TOOLS.

Manufacturer-sourced procedures and error codes — 126 brands, 400,000+ codes — served over REST API and MCP into your chatbot, CMMS or support stack. No rebuild.

Manufacturer-sourced answers, with the manual page
No exact manual? The API abstains — never billed
18 frozen cases on HVAC-Bench V1 — 0/12 unsafe answers

Book a demo Free Developer key

Abstentions never billed
Sources cited page by page
Data hosted and processed in Europe

Your stack

Chatbot · CMMS · Support

AskMarcel API & MCP

REST · MCP · SDK

Sourced answer

Manual · page · section

THE RISK OF A RAW LLM

A GENERALIST LLM
HALLUCINATES ON HVAC.

A hallucination is not a display glitch. It is a destroyed compressor, a wasted truck roll, a lost customer.

See the HVAC-Bench numbers

Technical hallucination

Ohmic values, pressures or procedures invented — impossible to verify without the manual.

Immediate field cost

Return visit, wrongly ordered part, hotline saturated confirming what the bot should have known.

Lost customer trust

A wrong answer on the phone or e-commerce chat is paid for in bad reviews and after-sales load.

Saturated hotline

Your L2/L3 experts answer all day questions the manufacturer manual solves in 30 seconds.

HOW IT WORKS

THREE STEPS. ZERO REBUILD.

Keep your stack

Chatbot, voicebot, CMMS, field-service or customer support — we replace nothing.

Plug the API or the MCP

REST API for your HTTP integrations, MCP server for Claude Desktop, ChatGPT or your agents. Same engine, same contract.

Your prompt stays in charge

Support level L1/L2/L3, tone, human escalation — you drive the experience.

ManyChatElevenLabsVoiceflowIntercomChatfuelClaudeChatGPTGeminiMCP

FOR YOUR DEVELOPERS

TWO SURFACES. ONE ENGINE.

The same HVAC knowledge, the same diagnostics — over HTTP or JSON-RPC.

REST API

api.askmarcel.app/v1

Sourced lookup, document search, procedures and diagnostic sessions over HTTP JSON.

Public OpenAPI contract — /v1/openapi.json
Strict SKU provenance: no exact manual → abstention
Idempotency-Key on every mutation

MCP SERVER

mcp.askmarcel.app/api/mcp

10 GA tools + 5 in Diagnostic Guide Beta, for Claude Desktop, ChatGPT and your agents.

OAuth 2.0 with consent
Public, verifiable MCP manifest
Typed NPM SDK: @askmarcel/sdk

Try it in 30 seconds

curl "https://api.askmarcel.app/v1/error-codes/daikin/7H?model=Altherma%203%20HT" \
  -H "Authorization: Bearer $ASKMARCEL_API_KEY"

Free Developer key — 50 requests/month
no_exact_source abstentions never billed
Manufacturer citations: document + page

BEYOND LOOKUP

BETA

THE HARNESS: GUIDED DIAGNOSTICS, STEP BY STEP.

A stateful session that proposes the next discriminating check, fences off risky actions and ends with a deterministic summary — no LLM.

Open a session

Brand, model, fault code or symptom: the equipment is resolved; the manufacturer result is journaled and the current Beta pack applies.

Propose the next check

A discriminating, safe action, cited from the manufacturer manual.

Take in the field answer

Typed measurement or natural language — hypotheses are recomputed.

Export the summary

Deterministic report, no LLM, exportable for 90 days.

Session projection (real excerpt)

{
  "release_channel": "beta",
  "hypotheses": [
    {
      "cause_id": "discharge_sensor",
      "label": "Discharge sensor",
      "rank": 1,
      "support_level": "high"
    }
  ],
  "next_action": {
    "action_id": "measure_discharge_sensor_resistance",
    "decision_role": "discriminating_measurement",
    "source_basis": "manufacturer",
    "citations": [
      { "document_id": "…", "page_start": 170 }
    ]
  }
}

Quota consumed at creation only: reads, responses and summaries unmetered
A risky action is never proposed without an applicable procedure
Air-to-water and air-to-air heat pumps — an honestly scoped Beta

Request Beta access

Beta: air-to-water & air-to-air heat pumps · access on request

HVAC-BENCH V1

PROOF, NOT PROMISES

HVAC-Bench V1, frozen 2026-08-31: 18 cases frozen before scoring, 97 scored answers. Exact proof 5/5, 5/5, 4/5 depending on the model · correct abstention 8/9, 9/11, 3/9 · 0/12 unsafe answers. Protocol and limits on /preuve.

See the full benchmark

HVAC-Bench V1 frozen cases

Compatible Claude · ChatGPT · Gemini

INTEGRATION GUIDES

PLUG MARCEL IN ONE AFTERNOON.

Step-by-step tutorials, connector by connector.

Claude Desktop

MCP server in 2 minutes: Claude cites manufacturer procedures.

Read the tutorial

ChatGPT

Your GPT troubleshoots with sources, not with its memory.

Read the tutorial

ElevenLabs

After-sales voicebot: Marcel answers the phone, manual in sight.

Read the tutorial

ManyChat

After-sales chatbot: error-code lookup right inside your flows.

Read the tutorial

n8n · Make · Zapier

Automate after-sales answers without writing code.

Read the tutorial

Chatfuel

Coming soon

Manufacturer knowledge inside your Chatfuel automations.

Voiceflow

Coming soon

Voice and chat agents wired to the AskMarcel base.

INTEGRATION OFFER

« MARCEL INSIDE »

Tailored

integration included

Integration support on your existing stack
Priority access to the Diagnostic Guide — Beta diagnostic sessions
Then the Business tier at €149/month — same path as the API

Book a demo Get a Developer key

Business €149/month ex VAT

API PRICING

START FREE. SCALE WITHOUT REWIRING.

Developer to test. Starter and Business activate self-serve. Marcel Inside installs on your stack with our support.

We only bill what we know

A request is only counted when the answer is sourced and usable. Errors and empty responses are free.

Developer

Testing, POC, personal agents

Free

50 requests/month — hard cap
REST API + MCP server
“Powered by AskMarcel” attribution
Testing and POC — production not permitted

Create a free key

Starter

Indies, integrators

€29/ month excl. VAT

Production use permitted
REST + MCP, no attribution
Webhooks & email support
500 requests/month included

Choose Starter

Popular

Business

Service companies, CMMS/ERP vendors

€149/ month excl. VAT

Contractual SLA & high rate limits
Citable source — manual + page
Priority support · unlimited seats
Fair use: 5,000 requests/month

Choose Business

Scale / White-label

Manufacturers, distributors, large vendors

Setup from €5,000+ subscription from €490/month

Dedicated volume
White-label
Custom corpus
Account manager

Talk to the team

Hard cap per tier (v4): no overage packs and no postpaid billing.
2 months free when paid annually upfront: Starter €290/year, Business €1,490/year.
Marcel Inside installs on your stack with our support.
A single avoided site revisit (€150+) pays for a year of Starter.

Field technician? See app pricing →

Are you a developer? Read the technical docs →

Frequently asked questions

What decision-makers ask us before an integration.

Another question? Contact our team

Ready to plug Marcel in?

A free Developer key to test tonight. Assisted integration to go to production.

Book a demo See the hard numbers

MANUFACTURER KNOWLEDGE.INSIDE YOUR TOOLS.

A GENERALIST LLMHALLUCINATES ON HVAC.

Technical hallucination

Immediate field cost

Lost customer trust

Saturated hotline

THREE STEPS. ZERO REBUILD.

Keep your stack

Plug the API or the MCP

Your prompt stays in charge

TWO SURFACES. ONE ENGINE.

THE HARNESS: GUIDED DIAGNOSTICS, STEP BY STEP.

Open a session

Propose the next check

Take in the field answer

Export the summary

PROOF, NOT PROMISES

PLUG MARCEL IN ONE AFTERNOON.

Claude Desktop

ChatGPT

ElevenLabs

ManyChat

n8n · Make · Zapier

Chatfuel

Voiceflow

« MARCEL INSIDE »

START FREE. SCALE WITHOUT REWIRING.

Frequently asked questions

What is an MCP server for HVAC?

Does the API cover my brand's error codes?

Can we plug AskMarcel into our CMMS or field-service tool?

What happens when AskMarcel doesn't know?

Do you also equip our competitors?

How is our data protected?

Can we test before committing to integration?

Ready to plug Marcel in?

MANUFACTURER KNOWLEDGE.
INSIDE YOUR TOOLS.

A GENERALIST LLM
HALLUCINATES ON HVAC.