Skip to content
    Case study · Standalone project

    Compass

    Every address has a story. Compass reads it before you sign.

    Open data turned into traceable, address-level context for commercial location decisions in Paris.

    Type
    Data product · Commercial premises · Paris · 2026
    Role
    Product and data design, built by directing AI coding agents.
    Status
    Corpus and MCP server live. Web demo on a frozen sample (17th arrondissement).
    Read withChatGPTClaude

    Sec. 01

    One address, read in context

    10 rue Mandar, Paris 2e. What public data says about it, exactly as the Compass server returned it on 7 October 2026.

    Fig. 1.1 · Address dossierServer output · 7 October 2026

    The address

    Six goodwill sales in seven years.

    1. Census · Withheld, licence not cleared

      Undetermined
    2. Goodwill sold€100,000

      Probable
    3. Goodwill sold€95,000

      Probable
    4. Goodwill sold€450,000

      Probable
    5. Census · Withheld, licence not cleared

      Undetermined
    6. Goodwill sold€87,500

      Probable
    7. Census · Asian restaurant

      Established
    8. Goodwill sold€175,000

      Probable
    9. Goodwill sold€120,000

      Probable

    Why Probable: two shopfronts share this street number, and the legal notice does not say which one was sold.

    Three insolvency notices also carry this address. They give a company's registered office, not the shop, and are flagged as such.

    Compass also measures how many businesses of a given trade are still trading six years later, neighbourhood by neighbourhood. Those figures rest on the 2017 census and stay withheld until its licence is cleared.

    The surroundings

    Dense commercial fabric, sustained passing trade, strong rail access, many shops and services within walking distance.

    The server's own one-sentence reading of the 800 m around the address, translated from French.

    Against another address

    Context only means something by comparison.

    Against another address
    Axis (score out of 100)10 rue Mandar, 2eA residential point, 20e
    Commercial density9582
    Shops and services within walking distance6422
    Food shops6122
    Rail access6070
    Passing trade (estimate)8378
    Road noise exposure (modelled)51100

    On road noise, the residential point comes out twice as exposed: 100 against 51. This is a model built from the major roads within 500 m, not a measurement.

    Six other axes (schools, healthcare, groceries, parks, transit, walkability) reach the ceiling at both points, as they do across much of central Paris. The server excludes them from the comparison instead of presenting them as a difference.

    ConfidenceEstablishedCorroboratedProbableUndeterminedHover or focus a level for its definition.
    10 rue Mandar, Paris 2e. Sources: APUR BDCom 2023 (ODbL), BODACC (Licence Ouverte). Retrieved 7 October 2026.
    Sec. 02

    Product strategy

    Join public data at the address, and refuse what cannot be verified.

    The problem

    An entrepreneur chooses a shopfront on one visit, a hunch about passing trade, and what the landlord says. Listings describe the unit: floor area, rent, photos. Nothing describes the street.

    More than 2,000 goodwill sales are published with their price in Paris every year. Each one is a decision made with that little.

    The bet

    The answer is already public, in pieces nobody joins at the address:

    • the licensed 2023 door-to-door census of every Paris shopfront (APUR);
    • legal notices of goodwill sales and insolvencies (BODACC);
    • the business register (INSEE Sirene).

    Earlier census records stay withheld until their licence is cleared.

    Compass joins them: 85,418 units, each figure with its source, licence and date.

    What it refuses

    What it refuses
    RefusedWhat that buys
    A single score out of 100A bakery wants footfall, a yoga studio wants quiet. One score averages that away.
    A rent estimateHonesty on the number everyone wants. No open dataset of commercial rents exists in France.
    Brokers as usersDepth for one person studying one address. Brokers get the API.
    Any figure without a cited public sourceA claim the reader can re-derive, including against Compass.

    Against what exists

    Against what exists
    Existing toolWhat it answersWhat it leaves out
    Listing portalsWhat is on the market todayWhat the street did before, and what is about to come free
    Footfall vendorsHow many people passA modelled figure from a phone panel the buyer cannot inspect
    Broker platformsMany locations, compared in bulkOne address, read in depth by the person who will sign

    Compass sits upstream of the listing: a business that has ceased trading or entered insolvency is public months before any advert.

    Sec. 03

    Where AI sits

    Design, planned for Q4 2026.

    AI stays out of the scoring core, which is deterministic and replayable. It works above it: reading legal notices, matching a sale to one of several shopfronts at the same address, explaining a result for a given trade. Everything it produces is labelled derived or probable, never established.

    Ruled out: a generated rent or revenue, a probability of success, a score "explained by AI".

    Sec. 04

    Built for people and AI agents

    Agent-ready · MCP server published · six tools · read-only

    One scoring core. A person reads it on a map, an AI agent queries it directly.

    Fig. 4.1

    Public sources (APUR BDCom, BODACC, INSEE Sirene)

    One scoring core

    • Map, for a person
    • MCP server, for an agent
    The same core serves both.
    Built for people and AI agents
    ToolWhat it answers
    trace_premiseWhat happened at this address, year by year
    find_premisesWhich shopfronts sit near this point
    score_locationHow this location scores, axis by axis
    compare_locationsHow two locations differ
    explain_scoreWhy one score is what it is
    list_sourcesWhich datasets, licences and dates are behind it

    What an agent receives

    {
      "occurred_on": "2021-08-05",
      "source": "BODACC cession",
      "source_licence": "Licence Ouverte",
      "kind": "sale",
      "amount_eur": 87500,
      "evidence": "Fonds acquis par achat au prix stipulé de 87500,00 euros.",
      "confidence": "probable",
      "confidence_reason": "2 locaux partagent cette adresse : lequel est concerné n'est pas publié"
    }

    One row of trace_premise for 10 rue Mandar, excerpt. Same fact, same source, same confidence level as in the timeline above.

    An agent gets no shortcut: same figures, same sources, same confidence levels as the person.

    Try it

    npx -y paris-compass-mcp
    Sec. 05

    How sure is it?

    Every figure is checked against automatic rules before it ships, every day.

    Each one carries one of four confidence levels. About half the corpus is certain. A third stays "probable", because public sources name an address and several shopfronts often share it. The product says so on screen.

    Read the four confidence definitions in Sec. 01.

    Fig. 5.1
    01Established
    51%
    02Corroborated
    6%
    03Probable
    37%
    04Undetermined
    6%
    Confidence levels across the corpus, measured 6 October 2026.
    Sec. 06

    Where it stands

    Where it stands
    ComponentState
    Corpus and evaluationLive
    MCP serverPublished
    Web demoFrozen sample, 17th arrondissement
    Demo on the live corpusIn progress
    AI layerDesign
    Share and reuse
    EmailMarkdown

    Schedule a conversation

    © Ivan de Murard. All rights reserved.

    Thank you for your time.

    In a crowded field, sustained attention is the rarest courtesy. I hope this work offered both enlightenment and quiet clarity.

    Conceived and crafted in Paris · Built 0→1 · Verified through open specifications

    © 2026 Ivan de Murard · Curated with Care