AskMarcel HVAC Technical Knowledge

io.github.askmarcelPublished by GitHub account askmarcelv1.3.1-beta.1Updated Oct 24, 2026

15 HVAC MCP tools: lookups, SKU provenance, guided PAC, Beta Harness sessions. 126 brands.

VerifiedStreamable HTTPWeb executableLocation & Lifestyle Knowledge & Memory

Server details

Identifier: io.github.askmarcel/mcphvac
Transport: Streamable HTTP
Runtime: Web executable
Trust: Verified
Published: Sep 16, 2026

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Overview

AI-generated overview

Remote MCP server giving assistants manufacturer-sourced HVAC technical documentation: error codes, procedures, product sheets and guided diagnostics with cited

What you can do: Search technical documentation semantically, filtered by brand, model or error code, and retrieve full procedures by chunk ID, with signed short-lived links to specific PDF pages for verification. Look up error codes deterministically and fetch product sheets with specs, composition and frequent faults by brand and model. Resolve a brand and model to a canonical SKU and check documentary coverage flags such as exact manual and error-code coverage. Run one-shot sourced diagnostics from a symptom or error code, with a strict-SKU variant that abstains when no exact-model manual exists. Run multi-turn guided troubleshooting for air-to-water heat pumps, or a stateful beta diagnostic session where
When to use it: Useful when an assistant must answer HVAC field questions — refrigerant charge, error-code meanings, wiring, fault trees — and the answer must cite the exact manufacturer manual and page rather than be guessed. Suited to technicians, support bots and agents serving the European HVAC market in French or English.
Requirements: Remote Streamable HTTP endpoint; nothing to install or self-host. Authentication is required: either an API key sent as a Bearer Authorization header or OAuth 2.0 with PKCE and dynamic client registration. An API key is created on the developer portal; the free Developer tier allows 250 calls per month. Network access to the hosted endpoint.

Before you install

Requires an API key or OAuth credentials, which should be kept secret. Usage is metered: the free tier is capped at 250 calls per month, and paid plans or a pilot are offered for higher volume, so calls can incur cost. The beta diagnostic session tools are marked beta and their packs are mutable; the server states a qualified HVAC professional is required. Diagnostic output is advisory and should be verified against the cited manual page.

Installation

In SourceWeft

Open AskMarcel HVAC Technical Knowledge in the dashboard and add it to a workspace.
Connect the required credentials. They are stored privately and never shown on public pages.
Enable the server for the chats that should use its tools.

Web executable via Streamable HTTP. Remote servers run from the web runtime once configured in a workspace.

Use with an agent

Paste this prompt into Claude Code, Codex, Cursor or another agent — or into SourceWeft chat. The agent reads this server's install guide, shows you its publisher, endpoint and sign-in, and adds it to your client once you agree. Keys never go into a command.

Read https://sourceweft.com/mcp/io.github.askmarcel%2Fmcphvac/install.md and connect the MCP server it describes to my client. Before changing any config, show me its publisher, endpoint and sign-in method and wait for my OK. Never put an API key in a command or in a file I would commit; ask me where it should come from.

Read the install guide the agent follows

Other MCP clients

Add this to your client's mcpServers config. The client completes OAuth sign-in on first connect.

{
  "mcpServers": {
    "askmarcel-hvac-technical-knowledge": {
      "type": "http",
      "url": "https://mcp.askmarcel.app/"
    }
  }
}

README

[AskMarcel]

AskMarcel — HVAC Technical Knowledge MCP Server

Manufacturer-sourced HVAC technical documentation for AI agents: search, diagnostics, error codes, procedures and product sheets across 126 brands and 905 models.

[MCP Registry] [smithery badge] [Transport] [Auth] [License]

AskMarcel is a remote, hosted MCP server (Streamable HTTP). There is nothing to install or self-host — point your MCP client at the endpoint and authenticate. The server connects AI agents to real manufacturer documentation so answers cite the exact manual and page number instead of hallucinating.

Endpoint: https://mcp.askmarcel.app
Registry name: io.github.askmarcel/mcphvac
Manifest: 1.3.1-beta.1 — 15 tools live in production
Docs & API key: https://app.askmarcel.app/developers
Reference: https://app.askmarcel.app/developers/reference
Marcel Inside (B2B API / MCP): https://askmarcel.app/fr/connecteurs
Free Developer tier: 250 API calls / month

Marcel Inside — branch it behind your bot

Use AskMarcel as Marcel Inside: plug manufacturer-sourced HVAC knowledge behind your existing chatbot, voicebot, or agent — without rebuilding your stack. Compatible with ManyChat, ElevenLabs, Voiceflow, Intercom, Claude, ChatGPT, Gemini, and custom MCP clients.

Sales & pilot: https://askmarcel.app/fr/connecteurs (490€ pilot, Business 149€/mois HT)
Developer sandbox: free tier — 250 calls/month at https://app.askmarcel.app/developers

Why AskMarcel

General-purpose LLMs guess at HVAC specifics — refrigerant charge, error-code meanings, wiring, fault trees. AskMarcel grounds every response in indexed manufacturer PDFs and returns the source page, so a field technician or an agent can trust and verify the answer. See HVAC-Bench for measured accuracy vs. raw LLM output.

126 brands · 905 models · 400,000+ error codes indexed
Deterministic error-code lookup (not a guess)
Strict SKU provenance (resolve_model, get_model_coverage, diagnose_v2) — no family substitution
Sourced one-shot lookups (diagnose) and multi-turn guided troubleshooting for air-to-water heat pumps (diagnose_guided)
LIVE Beta Harness sessions — stateful diagnostic loop with manufacturer DB lookup at session start (start_diagnostic … get_diagnostic_summary)
FR / EN, focused on the European HVAC/RACH market

Harness session vs `diagnose_guided`

Surface	Use when	Quota
Harness session (`start_diagnostic` …)	Multi-turn field diagnostic on PAC Air/Eau or PAC Air/Air with hypotheses, discriminating `next_action`, technician journal	Once at session creation
`diagnose_guided`	Legacy guided loop for PAC Air/Eau only — server-sealed state via `continuation`	Per turn
`diagnose_v2`	One-shot strict SKU lookup	Per successful call
`diagnose`	One-shot lookup without SKU gate	Per successful call

Harness Beta is live in production (DIAGNOSTIC_SESSIONS_PUBLIC=true). At start_diagnostic, the server looks up error codes in technical_error_codes (manufacturer DB) and journals the result — not only pack fallback maps. Active packs: pac_air_eau and pac_air_air at 0.0.1 (mutable during Beta).

Tools

The server exposes 15 tools (10 GA + 5 Beta Harness session). Full reference in docs/tools.md.

GA (10)

Tool	What it does
`search_technical_docs`	Semantic search over technical documentation (≤10 excerpts). Filter by `brand`, `model`, `error_code`.
`get_procedure`	Retrieve a full procedure by `chunk_id`.
`get_error_code`	Deterministic lookup by `brand` + `error_code` (optional `model`).
`get_product_sheet`	Product sheet: specs, composition, frequent error codes, by `brand` + `model`.
`get_pdf_page_snapshot`	Signed, 5-minute URL to a specific PDF page (`document_id` + `page`).
`diagnose`	One-shot sourced lookup from a symptom or error code (excerpt + steps + citation).
`diagnose_v2`	Same lookup with strict SKU provenance. Abstains (`diagnostic: null`) if no approved exact-model manual exists.
`resolve_model`	Resolve `brand` + `model` to a canonical SKU. Exact or alias only — never a series LIKE.
`get_model_coverage`	Documentary flags for a resolved SKU: `exact_manual`, `error_code_covered`, `market_verified`.
`diagnose_guided`	Multi-turn guided troubleshooting for air-to-water heat pumps (legacy; quota per turn).

Beta — Harness session (5)

Tool	What it does
`start_diagnostic`	Open a stateful Harness session. Manufacturer error-code lookup at start. Quota on creation.
`get_diagnostic`	Read current session projection (`hypotheses`, `next_action`, fault code).
`respond_to_diagnostic`	Append typed observation, measurement, or technician assessment.
`close_diagnostic`	Close session with optional reason (verification not required).
`get_diagnostic_summary`	Deterministic exportable summary from the session journal.

Stability: beta · release_channel: beta on responses · qualified HVAC professional required.

Quick start

1. Get an API key

Create a free key at https://app.askmarcel.app/developers (250 calls/month on the Developer tier). The server also supports OAuth 2.0 (PKCE + Dynamic Client Registration) for clients that discover auth automatically.

2. Connect your MCP client

Ready-to-use configs live in examples/. The general form for any Streamable HTTP MCP client:

json

{  "mcpServers": {    "askmarcel": {      "type": "streamable-http",      "url": "https://mcp.askmarcel.app",      "headers": {        "Authorization": "Bearer YOUR_API_KEY"      }    }  }}

{  "mcpServers": {    "askmarcel": {      "type": "streamable-http",      "url": "https://mcp.askmarcel.app",      "headers": {        "Authorization": "Bearer YOUR_API_KEY"      }    }  }}

Claude Desktop / Cursor / VS Code: see the matching file in examples/. Replace YOUR_API_KEY with your key.

3. Ask a question

Once connected, prompt naturally, e.g.:

"Daikin Altherma showing error U4 — what does it mean and how do I clear it?"

The agent calls resolve_model / diagnose_v2 (or get_error_code / diagnose) and returns the cause, the fix steps, and the source manual page — or an explicit abstention when no exact manual exists.

For a full field diagnostic loop on a heat pump, use start_diagnostic → respond_to_diagnostic → close_diagnostic (see skill hvac-harnais-session).

MCP vs Chat API

AskMarcel exposes two separate integration surfaces — do not mix their protocols:

Surface	Endpoint	Protocol	Use case
MCP server (this repo)	`https://mcp.askmarcel.app`	JSON-RPC Streamable HTTP (`tools/call`)	Connect Claude, Cursor, VS Code, or any MCP client to HVAC tools
Chat API (web / mobile / extension)	`https://app.askmarcel.app/api/chat`	AI SDK v5 SSE (`UIMessageStream`)	Full conversational UI with streaming, tools, and document blocks

The MCP server does not use the AI SDK chat stream (text-delta, data-* parts). If you build a custom agent with the Vercel AI SDK, use MCP tools via JSON-RPC — not the web chat endpoint.

Authentication

Two supported methods (details in docs/authentication.md):

API key (Bearer): Authorization: Bearer YOUR_API_KEY
OAuth 2.0: discovery via https://mcp.askmarcel.app/.well-known/oauth-protected-resource

Claude Skills

The skills/ folder contains ready-to-use Agent Skills that wrap these tools into HVAC workflows:

hvac-error-lookup — turn a brand + error code into a sourced explanation and fix.
hvac-diagnostic — one-shot symptom lookup with citations (diagnose).
hvac-guided-diagnosis — multi-turn guided troubleshooting for air-to-water heat pumps (diagnose_guided).
hvac-harnais-session — Beta Harness session loop (start_diagnostic … close_diagnostic).

REST API SDK

For custom agents that call the REST API directly (not MCP), use the npm package @askmarcel/sdk — includes Harness session methods (startDiagnosticSession, respondToDiagnosticSession, …), guidedTurn() for POST /v1/diagnostic/turn, plus resolveModel() / getModelCoverage() / V2 diagnose.

License

Code and content in this repository (documentation, examples, skills) are released under the MIT License. The AskMarcel hosted service and its underlying data are proprietary and governed by the AskMarcel terms.

🇫🇷 En français

AskMarcel est un serveur MCP distant et hébergé (Streamable HTTP) qui connecte les agents IA à la documentation technique HVAC/RACH sourcée constructeur. Rien à installer : on pointe son client MCP sur l'endpoint et on s'authentifie. Chaque réponse cite le manuel et la page exacte plutôt que d'halluciner.

Endpoint : https://mcp.askmarcel.app
Nom registre : io.github.askmarcel/mcphvac
Manifeste : 1.3.1-beta.1 — 15 outils en production
Doc & clé API : https://app.askmarcel.app/developers
Marcel Inside (B2B) : https://askmarcel.app/fr/connecteurs
Tier Developer gratuit : 250 appels / mois
Couverture : 126 marques · 905 modèles · 400 000+ codes erreur indexés

Marcel Inside — branchez la base AskMarcel derrière votre chatbot, voicebot ou agent existant. Pilote 490€ · Business 149€/mois HT · tier Developer gratuit pour tester.

15 outils : 10 GA (search_technical_docs, get_procedure, get_error_code, get_product_sheet, get_pdf_page_snapshot, diagnose, diagnose_v2, resolve_model, get_model_coverage, diagnose_guided) + 5 session Harnais Beta (start_diagnostic, get_diagnostic, respond_to_diagnostic, close_diagnostic, get_diagnostic_summary).

Harnais Beta LIVE : lookup DB fabricant (technical_error_codes) au start_diagnostic, packs pac_air_eau / pac_air_air 0.0.1, quota à la création de session seulement. Distinct de diagnose_guided (guidé legacy PAC Air/Eau, quota par tour).

Skills : lookup code erreur, diagnostic one-shot, guidé PAC, session Harnais — voir skills/.

SDK REST (npm) : @askmarcel/sdk — sessions Harnais + guidedTurn() + API v2.

Connexion rapide : créez une clé sur https://app.askmarcel.app/developers, puis utilisez une des configs du dossier examples/ (Claude Desktop, Cursor, VS Code). Remplacez YOUR_API_KEY par votre clé.

MCP vs Chat API : ce dépôt documente le serveur MCP (JSON-RPC sur mcp.askmarcel.app). Le chat web/mobile utilise une API distincte (SSE AI SDK v5 sur /api/chat) — les deux protocoles ne sont pas interchangeables.

Détails des outils : docs/tools.md · Authentification : docs/authentication.md.

Source: README.md at commit df97f1c

Tools

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Version history

v1.3.1-beta.1LatestSep 16, 2026

Score

85% of the applicable checks met

How complete this listing is, computed from the registry entry, the endpoint and public sources. Not a rating of the server and not a statement that it is safe or working today: reachability is a dated check, and no installs or reviews go into the score.

Reached in the last 30 daysRequired25 pts
Auth declaredRequired10 pts
Tools listed15 pts
Answer tools/list without a credential, or ship a package that starts in a sandbox without one.
DescriptionRequired15 pts
Logo10 pts
Documentation15 pts
License10 pts

AskMarcel HVAC Technical Knowledge

Overview

Installation

In SourceWeft

Use with an agent

Other MCP clients

README

AskMarcel — HVAC Technical Knowledge MCP Server

Marcel Inside — branch it behind your bot

Why AskMarcel

Harness session vs diagnose_guided

Tools

GA (10)

Beta — Harness session (5)

Quick start

1. Get an API key

2. Connect your MCP client

3. Ask a question

MCP vs Chat API

Authentication

Claude Skills

REST API SDK

Links

License

🇫🇷 En français

Tools

Version history

Score

Harness session vs `diagnose_guided`