diff --git a/src/ifcchat/README.md b/src/ifcchat/README.md
new file mode 100644
index 0000000000..355bce73e5
--- /dev/null
+++ b/src/ifcchat/README.md
@@ -0,0 +1,21 @@
+IfcOpenShell AI Assistant 
+=========================
+
+A web-based client-side (pyodide + OpenAI API) model interrogation and generation API based on: ifcedit, ifcquery and ifcmcp packaged in a HTML+JS application.
+
+### Setup instructions
+
+```
+mkdir ./src/chat/dist
+cd ./src/ifcquery/
+python -m build
+cp ./dist/ifcquery-0.0.0-py3-none-any.whl ../chat/dist/
+cd ../../src/ifcedit
+python -m build
+cp ./dist/ifcedit-0.0.0-py3-none-any.whl ../chat/dist/
+cd ../../src/ifcmcp
+python -m build
+cp ./dist/ifcmcp-0.0.0-py3-none-any.whl ../chat/dist/
+cd ../chat/dist/
+wget https://files.pythonhosted.org/packages/82/3d/14ce75ef66813643812f3093ab17e46d3a206942ce7376d31ec2d36229e7/lark-1.3.1-py3-none-any.whl
+```
\ No newline at end of file
diff --git a/src/ifcchat/app.js b/src/ifcchat/app.js
new file mode 100644
index 0000000000..22cbecc809
--- /dev/null
+++ b/src/ifcchat/app.js
@@ -0,0 +1,320 @@
+// app.js
+const $ = (id) => document.getElementById(id);
+
+const statusEl = $("status");
+const msgsEl = $("msgs");
+const sendBtn = $("send");
+const inputEl = $("input");
+const apiKeyEl = $("apiKey");
+const modelEl = $("model");
+const ifcFileEl = $("ifcFile");
+const newBtn = $("newModel");
+const downloadBtn = $("downloadIfc");
+
+function setBusy(isBusy, reason = "") {
+    const controls = [
+        $("send"),
+        $("newModel"),
+        $("downloadIfc"),
+        $("ifcFile"),
+    ];
+
+    for (const el of controls) el.disabled = isBusy;
+
+    $("input").disabled = isBusy;
+
+    const browseBtn = $("browseBtn");
+    if (browseBtn) {
+        browseBtn.classList.toggle("disabled", isBusy);
+        browseBtn.setAttribute("aria-disabled", isBusy ? "true" : "false");
+        browseBtn.tabIndex = isBusy ? -1 : 0;
+    }
+
+    setStatus(isBusy ? (reason || "Working…") : "Ready");
+}
+
+function addMessage(role, text) {
+    if (text.ok) {
+        text = text.data;
+    }
+    const wrap = document.createElement("div");
+    wrap.className = `msg ${role}`;
+    wrap.innerHTML = `
+    <div class="role">${role}</div>
+    <div class="bubble"></div>`;
+    const bubble = wrap.querySelector(".bubble");
+    bubble.textContent = text;
+    bubble.onclick = function () {
+        if (bubble.scrollHeight > 100 && role === "tool") {
+            bubble.style.maxHeight = bubble.style.maxHeight == 'none' ? '' : 'none';
+            bubble.style.borderBottom = bubble.style.borderBottom == '' ? 'dotted 2px gray' : '';
+        }
+    }
+    msgsEl.appendChild(wrap);
+    msgsEl.scrollTop = msgsEl.scrollHeight;
+}
+
+function setStatus(text) {
+    statusEl.textContent = text;
+}
+
+const worker = new Worker("./ifc_worker.js", { type: "module" });
+
+function callWorker(type, payload = {}) {
+    return new Promise((resolve, reject) => {
+        const id = crypto.randomUUID();
+        const onMsg = (ev) => {
+            const msg = ev.data;
+            if (!msg || msg.id !== id) return;
+            worker.removeEventListener("message", onMsg);
+            if (msg.ok) resolve(msg);
+            else reject(new Error(msg.error || "Worker error"));
+        };
+        worker.addEventListener("message", onMsg);
+        worker.postMessage({ id, type, payload });
+    });
+}
+
+// ---- OpenAI Responses API tool schemas (should match ifcmcp.core openai_tools()) ----
+// Docs show Responses API function_call items + function_call_output loop. :contentReference[oaicite:4]{index=4}
+const tools = [
+    {
+        type: "function", name: "ifc_new", description: "Create a new empty IFC model in memory.",
+        parameters: { type: "object", properties: { schema: { type: "string" } }, required: [], additionalProperties: false }
+    },
+    {
+        type: "function", name: "ifc_summary", description: "Get a concise overview of the loaded IFC model.",
+        parameters: { type: "object", properties: {}, required: [], additionalProperties: false }
+    },
+    {
+        type: "function", name: "ifc_tree", description: "Get the full spatial hierarchy tree.",
+        parameters: { type: "object", properties: {}, required: [], additionalProperties: false }
+    },
+    {
+        type: "function", name: "ifc_select", description: "Select elements using ifcopenshell selector syntax (e.g. 'IfcWall').",
+        parameters: { type: "object", properties: { query: { type: "string" } }, required: ["query"], additionalProperties: false }
+    },
+    {
+        type: "function", name: "ifc_info", description: "Inspect an entity by STEP id.",
+        parameters: { type: "object", properties: { element_id: { type: "integer" } }, required: ["element_id"], additionalProperties: false }
+    },
+    {
+        type: "function", name: "ifc_relations", description: "Get relationships for an element. traverse='up' walks to IfcProject.",
+        parameters: {
+            type: "object", properties: { element_id: { type: "integer" }, traverse: { type: "string" } },
+            required: ["element_id"], additionalProperties: false
+        }
+    },
+    {
+        type: "function", name: "ifc_clash", description: "Run clash/clearance checks for an element.",
+        parameters: {
+            type: "object", properties: { element_id: { type: "integer" }, clearance: { type: "number" }, tolerance: { type: "number" }, scope: { type: "string" } },
+            required: ["element_id"], additionalProperties: false
+        }
+    },
+    {
+        type: "function", name: "ifc_list", description: "List ifcopenshell.api modules or functions within a module.",
+        parameters: { type: "object", properties: { module: { type: "string" } }, required: [], additionalProperties: false }
+    },
+    {
+        type: "function", name: "ifc_docs", description: "Get documentation for an ifcopenshell.api function, 'module.function'.",
+        parameters: { type: "object", properties: { function_path: { type: "string" } }, required: ["function_path"], additionalProperties: false }
+    },
+    {
+        type: "function", name: "ifc_edit", description: "Execute an ifcopenshell.api mutation; params is a JSON string of stringly-typed kwargs.",
+        parameters: { type: "object", properties: { function_path: { type: "string" }, params: { type: "string" } }, required: ["function_path"], additionalProperties: false }
+    },
+    {
+        type: "function", name: "ifc_validate", description: "Validate the loaded model. Returns valid bool and list of issues.",
+        parameters: { type: "object", properties: { express_rules: { type: "boolean" } }, required: [], additionalProperties: false }
+    },
+    {
+        type: "function", name: "ifc_schedule", description: "List work schedules and nested tasks. Use max_depth=1 for top-level phases only on large projects.",
+        parameters: { type: "object", properties: { max_depth: { type: "integer" } }, required: [], additionalProperties: false }
+    },
+    {
+        type: "function", name: "ifc_cost", description: "List cost schedules and nested cost items. Use max_depth=1 for top-level sections only on large BoQs.",
+        parameters: { type: "object", properties: { max_depth: { type: "integer" } }, required: [], additionalProperties: false }
+    },
+    {
+        type: "function", name: "ifc_schema", description: "Return IFC class documentation for an entity type.",
+        parameters: { type: "object", properties: { entity_type: { type: "string" } }, required: ["entity_type"], additionalProperties: false }
+    },
+    {
+        type: "function", name: "ifc_quantify", description: "Run quantity take-off (QTO) on the model. Modifies model in-place; call ifc_save() after.",
+        parameters: { type: "object", properties: { rule: { type: "string" }, selector: { type: "string" } }, required: ["rule"], additionalProperties: false }
+    },
+];
+
+const SYSTEM_INSTRUCTIONS = `
+You are an IFC copilot running in a browser. You can call tools to inspect or modify the currently loaded IFC model.
+Rules:
+- If the user asks about model contents (counts, lists, properties, hierarchy), use tools like ifc_summary/ifc_select/ifc_info/ifc_tree.
+- If the user asks to change the model, prefer: (1) ifc_list to find candidate API modules, (2) ifc_docs for the exact function signature, then (3) ifc_edit.
+- If there is no model and the user wants to create one, call ifc_new.
+- After edits, explain what changed and suggest downloading the IFC.
+Be concise. Avoid dumping huge trees unless asked.
+`;
+
+let inputItems = []; // running conversation state (Responses API style)
+
+async function openAIResponsesCreate({ apiKey, model, input, tools }) {
+    const res = await fetch("https://api.openai.com/v1/responses", {
+        method: "POST",
+        headers: {
+            "Content-Type": "application/json",
+            "Authorization": `Bearer ${apiKey}`,
+        },
+        body: JSON.stringify({
+            model,
+            instructions: SYSTEM_INSTRUCTIONS,
+            tools,
+            input,
+        }),
+    });
+
+    if (!res.ok) {
+        const text = await res.text();
+        throw new Error(`OpenAI error ${res.status}: ${text}`);
+    }
+    return await res.json();
+}
+
+function extractAssistantText(response) {
+    const out = [];
+    for (const item of response.output ?? []) {
+        if (item.type === "message" && item.role === "assistant") {
+            for (const c of item.content ?? []) {
+                if (c.type === "output_text") out.push(c.text);
+            }
+        }
+    }
+    return out.join("\n").trim();
+}
+
+async function runAgentTurn(userText) {
+    const apiKey = apiKeyEl.value.trim();
+    if (!apiKey) throw new Error("Missing API key");
+
+    // Add user message
+    inputItems.push({ role: "user", content: userText });
+
+    // Tool-calling loop (Responses API): append response.output, execute function_call items, append function_call_output.
+    for (let i = 0; i < 64; i++) {
+        const response = await openAIResponsesCreate({
+            apiKey,
+            model: modelEl.value,
+            input: inputItems,
+            tools,
+        });
+
+        // Keep ALL output items (incl reasoning/tool calls) in the running state.
+        inputItems.push(...(response.output ?? []));
+
+        // Show any assistant text immediately
+        const text = extractAssistantText(response);
+        if (text) addMessage("assistant", text);
+
+        const calls = (response.output ?? []).filter((x) => x.type === "function_call");
+        if (calls.length === 0) return;
+
+        for (const call of calls) {
+            let args = {};
+            try { args = call.arguments ? JSON.parse(call.arguments) : {}; }
+            catch { args = {}; }
+
+            addMessage("tool", `→ ${call.name}(${JSON.stringify(args)})`);
+
+            const toolRes = await callWorker("toolCall", { name: call.name, args });
+
+            // Feed tool result back to the model
+            inputItems.push({
+                type: "function_call_output",
+                call_id: call.call_id,
+                output: JSON.stringify(toolRes.result),
+            });
+
+            addMessage("tool", `← ${call.name}: ${JSON.stringify(toolRes.result, null, 2)}`);
+        }
+    }
+
+    addMessage("assistant", "I hit the tool-call loop limit. Try narrowing your request.");
+}
+
+sendBtn.onclick = async () => {
+    const text = inputEl.value.trim();
+    if (!text) return;
+    inputEl.value = "";
+    addMessage("user", text);
+    try {
+        setBusy(true, "Thinking…");
+        await runAgentTurn(text);
+        setBusy(false, "Ready");
+    } catch (e) {
+        setBusy(true, "Error");
+        addMessage("assistant", `Error: ${e.message}`);
+    }
+};
+
+inputEl.addEventListener("keydown", (e) => {
+    if (e.key === "Enter" && !e.shiftKey) {
+        e.preventDefault();
+        sendBtn.click();
+    }
+});
+
+ifcFileEl.onchange = async () => {
+    const f = ifcFileEl.files?.[0];
+    if (!f) return;
+    setBusy(true, "Loading IFC into Pyodide…");
+    const buf = await f.arrayBuffer();
+    try {
+        const r = await callWorker("loadIfc", { filename: f.name, bytes: buf }, [buf]);
+        addMessage("assistant", r.result);
+        setBusy(false, "Ready");
+    } catch (e) {
+        setStatus(true, "Error");
+        addMessage("assistant", `Load error: ${e.message}`);
+    }
+};
+
+newBtn.onclick = async () => {
+    try {
+        setBusy(true, "Creating new model…");
+        const r = await callWorker("toolCall", { name: "ifc_new", args: { schema: "IFC4" } });
+        addMessage("assistant", `New model: ${JSON.stringify(r.result)}`);
+        setBusy(false, "Ready");
+    } catch (e) {
+        setBusy(true, "Error");
+        addMessage("assistant", `Error: ${e.message}`);
+    }
+};
+
+downloadBtn.onclick = async () => {
+    try {
+        setBusy(true, "Exporting IFC…");
+        const r = await callWorker("exportIfc", {});
+        const blob = new Blob([r.bytes], { type: "application/octet-stream" });
+        const url = URL.createObjectURL(blob);
+        const a = document.createElement("a");
+        a.href = url;
+        a.download = r.filename || "model.ifc";
+        a.click();
+        URL.revokeObjectURL(url);
+        setBusy(false, "Ready");
+    } catch (e) {
+        setBusy(true, "Error");
+        addMessage("assistant", `Export error: ${e.message}`);
+    }
+};
+
+(async () => {
+    try {
+        setBusy(true, "Initializing Pyodide and IfcOpenShell for in-memory IFC access…");
+        await callWorker("init", {});
+        setBusy(false, "Ready");
+    } catch (e) {
+        setBusy(true, "Error");
+        addMessage("assistant", `Worker init failed: ${e.message}`);
+    }
+})();
\ No newline at end of file
diff --git a/src/ifcchat/ifc_worker.js b/src/ifcchat/ifc_worker.js
new file mode 100644
index 0000000000..903dcd1fe0
--- /dev/null
+++ b/src/ifcchat/ifc_worker.js
@@ -0,0 +1,108 @@
+// ifc_worker.js  (MODULE WORKER)
+import { loadPyodide } from "https://cdn.jsdelivr.net/pyodide/v0.29.3/full/pyodide.mjs";
+
+let pyodide = null;
+let callToolPy = null;
+let initPromise = null;
+
+function ok(id, extra = {}, transfer = []) {
+    self.postMessage({ id, ok: true, ...extra }, transfer);
+}
+function fail(id, error) {
+    self.postMessage({ id, ok: false, error: String(error?.message || error) });
+}
+
+async function ensurePyodide() {
+    if (initPromise) return initPromise;
+
+    initPromise = (async () => {
+        // Passing indexURL avoids some environments failing to infer it from the module URL. :contentReference[oaicite:3]{index=3}
+        pyodide = await loadPyodide({
+            indexURL: "https://cdn.jsdelivr.net/pyodide/v0.29.3/full/",
+        });
+
+        await pyodide.loadPackage("micropip");
+        await pyodide.loadPackage("numpy");
+        await pyodide.loadPackage("shapely");
+        await pyodide.loadPackage("typing-extensions");
+
+        const micropip = pyodide.pyimport("micropip");
+
+        // Detect python minor version (3.12 vs 3.13) and pick a matching wheel.
+        const pyVer = pyodide.runPython(`
+import sys
+f"{sys.version_info.major}.{sys.version_info.minor}"
+    `);
+
+        const wheelUrl =
+            pyVer === "3.13"
+                ? "https://ifcopenshell.github.io/wasm-wheels/ifcopenshell-0.8.3+34a1bc6-cp313-cp313-emscripten_4_0_9_wasm32.whl"
+                : "https://ifcopenshell.github.io/wasm-wheels/ifcopenshell-0.8.2+d50e806-cp312-cp312-emscripten_3_1_58_wasm32.whl";
+
+        await micropip.install(wheelUrl);
+
+        await micropip.install([
+            "./dist/ifcquery-0.0.0-py3-none-any.whl",
+            "./dist/ifcedit-0.0.0-py3-none-any.whl",
+            "./dist/ifcmcp-0.0.0-py3-none-any.whl",
+            "./dist/lark-1.3.1-py3-none-any.whl",
+        ])
+        await pyodide.runPythonAsync(`
+from ifcmcp.embedded import call_tool as _call_tool
+    `);
+        callToolPy = pyodide.globals.get("_call_tool");
+    })();
+
+    return initPromise;
+}
+
+function callTool(name, args) {
+    const pyArgs = pyodide.toPy(args);
+    const res = callToolPy(name, pyArgs);
+    pyArgs.destroy();
+    const resJs = res.toJs({ dict_converter: Object.fromEntries });
+    res.destroy();
+    return resJs;
+}
+
+self.onmessage = async (ev) => {
+    const { id, type, payload } = ev.data || {};
+    try {
+        if (type === "init") {
+            await ensurePyodide();
+            ok(id, { result: "ok" });
+            return;
+        }
+
+        await ensurePyodide();
+
+        if (type === "loadIfc") {
+            const { filename, bytes } = payload;
+            const path = `/tmp/${filename || "model.ifc"}`;
+            pyodide.FS.mkdirTree("/tmp");
+            pyodide.FS.writeFile(path, new Uint8Array(bytes));
+            const result = callTool("ifc_load", { path });
+            ok(id, { result });
+            return;
+        }
+
+        if (type === "exportIfc") {
+            const path = "/tmp/export.ifc";
+            const result = callTool("ifc_save", { path });
+            const data = pyodide.FS.readFile(path);
+            ok(id, { result, filename: "export.ifc", bytes: data }, [data.buffer]);
+            return;
+        }
+
+        if (type === "toolCall") {
+            const { name, args } = payload;
+            const result = callTool(name, args || {});
+            ok(id, { result });
+            return;
+        }
+
+        throw new Error(`Unknown message type: ${type}`);
+    } catch (e) {
+        fail(id, e);
+    }
+};
\ No newline at end of file
diff --git a/src/ifcchat/index.html b/src/ifcchat/index.html
new file mode 100644
index 0000000000..3d59ac1371
--- /dev/null
+++ b/src/ifcchat/index.html
@@ -0,0 +1,294 @@
+<!doctype html>
+<html lang="en">
+
+<head>
+    <meta charset="utf-8" />
+    <meta name="viewport" content="width=device-width, initial-scale=1" />
+    <title>IfcOpenShell AI Assistant</title>
+    <style>
+        * {
+            box-sizing: border-box;
+        }
+
+        body {
+            font-family: system-ui, sans-serif;
+            margin: 0;
+        }
+
+        button,
+        input,
+        select,
+        textarea {
+            font: inherit;
+        }
+
+        header {
+            padding: 12px 16px;
+            border-bottom: 1px solid #ddd;
+        }
+
+        header input,
+        header select {
+            padding: 8px;
+        }
+
+        main {
+            display: grid;
+            grid-template-columns: 320px 1fr;
+            height: calc(100vh - 84px);
+        }
+
+        .side {
+            border-right: 1px solid #ddd;
+            padding: 12px;
+            overflow: auto;
+        }
+
+        .chat {
+            display: flex;
+            flex-direction: column;
+            height: 100%;
+        }
+
+        .msgs {
+            flex: 1;
+            overflow: auto;
+            padding: 16px;
+        }
+
+        .msg {
+            margin: 10px 0;
+        }
+
+        .msg .role {
+            font-size: 12px;
+            opacity: 0.7;
+            margin-bottom: 4px;
+        }
+
+        .msg .bubble {
+            padding: 10px 12px;
+            border-radius: 10px;
+            white-space: pre-wrap;
+        }
+
+        .msg.user .bubble {
+            background: #e8f0ff;
+            align-self: flex-end;
+        }
+
+        .msg.assistant .bubble {
+            background: #f4f4f4;
+        }
+
+        .msg.tool .bubble {
+            background: #fff6db;
+            font-family: ui-monospace, SFMono-Regular, Menlo, monospace;
+            font-size: 12px;
+        }
+
+        .composer {
+            display: flex;
+            gap: 8px;
+            padding: 12px;
+            justify-content: center;
+        }
+
+        .composer textarea {
+            flex: 1;
+            resize: none;
+            height: 88px;
+            border: none;
+        }
+
+        .composer button {
+            align-self: center;
+        }
+
+        .composer .inner {
+            border: solid 1px #ddd;
+            border-radius: 20px;
+            padding: 10px;
+            display: flex;
+            width: 50%;
+        }
+
+        .status {
+            font-size: 12px;
+            opacity: 0.7;
+        }
+
+        section>.row>label {
+            display: block;
+            font-size: 12px;
+            opacity: 0.75;
+            margin-bottom: 6px;
+        }
+
+        .side .row {
+            margin-bottom: 10px;
+        }
+
+        .row button {
+            padding: 8px 10px;
+        }
+
+        #model {
+            background: white;
+            color: gray;
+            border: solid 1px #eee;
+            border-radius: 6px;
+        }
+
+        hr {
+            border: dashed 1px #ddd;
+        }
+
+        .btn-row {
+            display: flex;
+            gap: 10px;
+        }
+
+        .btn-row>.btn,
+        .btn-row>button.btn {
+            flex: 1 1 0;
+            min-width: 0;
+        }
+
+        .btn {
+            display: inline-flex;
+            align-items: center;
+            justify-content: center;
+            gap: 8px;
+            font-size: 14px;
+
+            padding: 10px 12px;
+            border-radius: 10px;
+            border: 1px solid #d0d0d0;
+            background: #eee;
+
+            cursor: pointer;
+            user-select: none;
+            text-decoration: none;
+        }
+
+        .btn:hover {
+            background: #ddd;
+        }
+
+        .btn:active {
+            transform: translateY(1px);
+        }
+
+        .btn-wide {
+            width: 100%;
+        }
+
+        .material-icons {
+            font-size: 18px;
+            line-height: 1;
+        }
+
+        /* Disabled state for label-button + normal buttons */
+        .btn.disabled,
+        .btn:disabled {
+            opacity: 0.55;
+            cursor: not-allowed;
+            pointer-events: none;
+        }
+
+        .msg.tool .bubble {
+            max-height: 100px;
+            overflow: hidden;
+        }
+
+        #input {
+            border: none;
+            outline: none;
+        }
+
+        #input:focus,
+        #input:focus-visible {
+            outline: none;
+            box-shadow: none;
+        }
+    </style>
+    <link href="https://fonts.googleapis.com/icon?family=Material+Icons" rel="stylesheet">
+</head>
+
+<body>
+    <header>
+        <div class="row">
+
+            <strong>IfcOpenShell AI Assistant</strong>
+            <select id="model">
+                <option value="gpt-5">gpt-5</option>
+                <option value="gpt-4.1">gpt-4.1</option>
+            </select>
+        </div>
+        <div class="row">
+
+            <span class="status" id="status">Booting…</span>
+        </div>
+    </header>
+
+    <main>
+        <section class="side">
+            <div class="row">
+                <label>OpenAI API key (stored only in memory)</label>
+                <input id="apiKey" type="password" placeholder="sk-..." autocomplete="off" style="width: 100%;" />
+            </div>
+
+            <hr />
+
+            <div class="row">
+                <label>IFC model (stored only in memory)</label>
+
+                <div class="btn-row">
+                    <label class="btn" id="browseBtn" for="ifcFile" role="button" tabindex="0">
+                        <span class="material-icons">folder_open</span>
+                        Browse
+                    </label>
+
+                    <button class="btn" id="newModel" type="button">
+                        <span class="material-icons">add_box</span>
+                        New IFC
+                    </button>
+                </div>
+
+                <input id="ifcFile" type="file" accept=".ifc,.ifczip,.ifcxml,.zip" hidden />
+            </div>
+
+            <div class="row">
+                <button class="btn btn-wide" id="downloadIfc" type="button">
+                    <span class="material-icons">download</span>
+                    Download IFC
+                </button>
+            </div>
+
+            <hr />
+
+            <div class="row">
+                <label>Tips</label>
+                <div class="status">
+                    • Upload an IFC, then ask “Summarize the model” or “List all IfcWalls”.<br />
+                    • Try “Add a new site and building named X” (will use ifc_edit).
+                </div>
+            </div>
+        </section>
+
+        <section class="chat">
+            <div class="msgs" id="msgs"></div>
+            <div class="composer">
+                <div class="inner">
+                    <textarea id="input" placeholder="Ask or instruct about the IFC model…"></textarea>
+                    <button id="send" class="btn">Send <span class="material-icons">send</span></button>
+                </div>
+            </div>
+        </section>
+    </main>
+
+    <script type="module" src="./app.js"></script>
+</body>
+
+</html>
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