diff --git a/functions/tools/bilig_workpaper_formula_readback/README.md b/functions/tools/bilig_workpaper_formula_readback/README.md
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+# Bilig WorkPaper Formula Readback
+
+Use a Bilig WorkPaper endpoint from Open WebUI to write an input cell, recalculate formulas, and return verified JSON readback.
+
+This is useful when an assistant needs spreadsheet-style business logic without opening Excel, driving a browser, or trusting stale cached formula values.
+
+## What it does
+
+- Sends `sheetName`, `address`, and `value` to a Bilig WorkPaper formula endpoint.
+- Confirms the endpoint reports `verified: true`.
+- Returns the edited cell, recalculated values, and persistence/readback fields as compact JSON.
+
+## Default endpoint
+
+The default valve points at the public Bilig forecast demo:
+
+```text
+https://bilig.proompteng.ai/api/workpaper/n8n/forecast
+```
+
+The default call writes `0.5` to `Inputs!B3`. The demo recalculates expected ARR from the workbook formulas.
+
+## Install
+
+1. In Open WebUI, go to `Workspace -> Tools`.
+2. Create a new tool.
+3. Paste `main.py`.
+4. Save and enable it for a model that supports tool calls.
+
+## Example prompt
+
+```text
+Set Inputs!B3 to 0.5 and show the verified formula readback.
+```
+
+The tool should return a JSON object with `verified: true`, the edited cell, and recalculated output fields.
+
+## Configuration
+
+Use valves to point the tool at your own Bilig endpoint:
+
+- `base_url`: Bilig service origin.
+- `formula_path`: endpoint path that accepts a formula-readback POST.
+- `timeout_seconds`: request timeout.
+
+The endpoint must accept JSON:
+
+```json
+{
+  "sheetName": "Inputs",
+  "address": "B3",
+  "value": 0.5
+}
+```
+
+`value` can be passed as a native JSON value or as a string containing a JSON
+literal. For example, `0.5`, `"0.5"`, `true`, and `"SKU-1"` are accepted.
diff --git a/functions/tools/bilig_workpaper_formula_readback/main.py b/functions/tools/bilig_workpaper_formula_readback/main.py
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+"""
+title: Bilig WorkPaper Formula Readback
+author: Greg Konush
+author_url: https://github.com/gregkonush
+git_url: https://github.com/proompteng/bilig
+description: Write an input cell to a Bilig WorkPaper endpoint, recalculate formulas, and return verified JSON readback.
+required_open_webui_version: 0.4.0
+version: 0.1.0
+license: MIT
+"""
+
+import json
+from typing import Any
+from urllib.error import HTTPError, URLError
+from urllib.parse import urljoin
+from urllib.request import Request, urlopen
+
+from pydantic import BaseModel, Field
+
+
+class Tools:
+    class Valves(BaseModel):
+        base_url: str = Field(
+            default="https://bilig.proompteng.ai",
+            description="Base URL for the Bilig WorkPaper service.",
+        )
+        formula_path: str = Field(
+            default="/api/workpaper/n8n/forecast",
+            description="Path for the formula readback endpoint.",
+        )
+        timeout_seconds: int = Field(
+            default=20,
+            ge=1,
+            le=120,
+            description="HTTP timeout for formula readback requests.",
+        )
+
+    def __init__(self):
+        self.valves = self.Valves()
+
+    async def verify_formula_readback(
+        self,
+        sheet_name: str = "Inputs",
+        address: str = "B3",
+        value: Any = "0.5",
+    ) -> str:
+        """
+        Write one input cell to a Bilig WorkPaper endpoint and return verified
+        formula readback.
+
+        :param sheet_name: Worksheet name, for example "Inputs".
+        :param address: A1-style cell address, for example "B3".
+        :param value: Cell value. JSON literals such as 0.5, true, or "SKU-1"
+            are accepted. Native JSON values from tool calls are also accepted.
+        """
+
+        payload = {
+            "sheetName": sheet_name,
+            "address": address,
+            "value": self._parse_value(value),
+        }
+        endpoint = urljoin(
+            self.valves.base_url.rstrip("/") + "/",
+            self.valves.formula_path.lstrip("/"),
+        )
+
+        try:
+            result = self._post_json(endpoint, payload)
+        except HTTPError as exc:
+            body = exc.read().decode("utf-8", errors="replace")
+            return json.dumps(
+                {
+                    "ok": False,
+                    "error": "bilig_http_error",
+                    "status": exc.code,
+                    "body": body[:1200],
+                },
+                indent=2,
+                sort_keys=True,
+            )
+        except URLError as exc:
+            return json.dumps(
+                {
+                    "ok": False,
+                    "error": "bilig_network_error",
+                    "reason": str(exc.reason),
+                },
+                indent=2,
+                sort_keys=True,
+            )
+        except Exception as exc:
+            return json.dumps(
+                {
+                    "ok": False,
+                    "error": "bilig_unexpected_error",
+                    "reason": str(exc),
+                },
+                indent=2,
+                sort_keys=True,
+            )
+
+        return json.dumps(self._summarize_result(result), indent=2, sort_keys=True)
+
+    def _post_json(self, endpoint: str, payload: dict[str, Any]) -> dict[str, Any]:
+        request = Request(
+            endpoint,
+            data=json.dumps(payload).encode("utf-8"),
+            headers={
+                "content-type": "application/json",
+                "accept": "application/json",
+                "user-agent": "open-webui-bilig-workpaper-tool/0.1.0",
+            },
+            method="POST",
+        )
+        with urlopen(request, timeout=self.valves.timeout_seconds) as response:
+            return json.loads(response.read().decode("utf-8"))
+
+    def _summarize_result(self, result: dict[str, Any]) -> dict[str, Any]:
+        after = result.get("after") if isinstance(result.get("after"), dict) else {}
+        before = result.get("before") if isinstance(result.get("before"), dict) else {}
+
+        return {
+            "ok": bool(result.get("verified")),
+            "verified": result.get("verified"),
+            "editedCell": result.get("editedCell"),
+            "persisted": result.get("persisted"),
+            "restoredReadbackMatches": result.get("restoredReadbackMatches"),
+            "before": {
+                "input": before.get("input"),
+                "expectedArr": before.get("expectedArr"),
+                "expectedCustomers": before.get("expectedCustomers"),
+            },
+            "after": {
+                "input": after.get("input"),
+                "expectedArr": after.get("expectedArr"),
+                "expectedCustomers": after.get("expectedCustomers"),
+            },
+        }
+
+    def _parse_value(self, raw_value: Any) -> Any:
+        if not isinstance(raw_value, str):
+            return raw_value
+
+        try:
+            return json.loads(raw_value)
+        except json.JSONDecodeError:
+            return raw_value