diff --git a/CHANGELOG.md b/CHANGELOG.md
index b4081da862..546bf8b1e8 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -10,6 +10,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 ### Added
 
 - Added a message after `npm i hyperformula` that points AI assistants to the SKILLS file. The message needs `--foreground-scripts` to be visible in npm, and pnpm 10 needs the `postinstall` script to be approved first. [#1829](https://github.com/handsontable/hyperformula/pull/1829)
+- Added `DetailedCellError.hasMessage`, so a consumer can tell a cell error that never carried a message (e.g. a custom function that omitted one) apart from one with a deliberately empty message — both previously surfaced identically as `message: ''`. [#1547](https://github.com/handsontable/hyperformula/issues/1547)
 
 ### Changed
 
diff --git a/docs/guide/custom-functions.md b/docs/guide/custom-functions.md
index 5a6021ef2d..ce5cfc6151 100644
--- a/docs/guide/custom-functions.md
+++ b/docs/guide/custom-functions.md
@@ -326,6 +326,12 @@ custom error messages. Put them to good use: let your users know what caused the
 error and how to avoid it in the future.
 :::
 
+Every error the engine raises while evaluating a formula carries a message. A custom function's
+`message` argument stays optional — if you omit it, a consumer reading the resulting
+`DetailedCellError` sees `message` as an empty string, the same value HyperFormula uses
+for "no message". To tell the two cases apart, check `hasMessage`: `true` means a
+message was set (even if it's a deliberately empty string), `false` means none was.
+
 ### Test your function
 
 To make sure your function works correctly, add unit tests. Use a JavaScript
diff --git a/hyperformula/src/CellValue.ts b/hyperformula/src/CellValue.ts
index 47930aad99..ffae216791 100644
--- a/hyperformula/src/CellValue.ts
+++ b/hyperformula/src/CellValue.ts
@@ -12,6 +12,18 @@ export class DetailedCellError {
   public readonly type: ErrorType
   public readonly message: string
 
+  /**
+   * Whether the underlying error carried a message at all.
+   *
+   * `message` collapses "no message" and "an empty message" into `''`; this flag
+   * keeps them apart for consumers that need to know whether a cause was stated.
+   * Errors the engine raises while evaluating a formula always carry a message. A
+   * `false` here means nobody stated a cause: a custom function that did not supply
+   * one, or an error value a user typed straight into a cell, where the cause is the
+   * typing itself and `originFunction` says so.
+   */
+  public readonly hasMessage: boolean
+
   constructor(
     error: CellError,
     public readonly value: string,
@@ -19,6 +31,7 @@ export class DetailedCellError {
   ) {
     this.type = error.type
     this.message = error.message ?? ''
+    this.hasMessage = error.message !== undefined
   }
 
   public toString(): string {
diff --git a/hyperformula/test/_setupFiles/matchers/cellErrorComparison.ts b/hyperformula/test/_setupFiles/matchers/cellErrorComparison.ts
index 2a9dfa15cf..3729bffec1 100644
--- a/hyperformula/test/_setupFiles/matchers/cellErrorComparison.ts
+++ b/hyperformula/test/_setupFiles/matchers/cellErrorComparison.ts
@@ -36,6 +36,7 @@ const IGNORED_IN_STRUCTURAL_COMPARE = {
   address: undefined,
   originFunction: undefined,
   argumentIndex: undefined,
+  hasMessage: undefined,
   propagated: undefined,
   originAddress: undefined,
   originAddressVersion: undefined,