feat: allow setting custom role description for blocks

packages/blockly/core/block.ts

@@ -53,6 +53,7 @@ import {Coordinate} from './utils/coordinate.js';
 import * as deprecation from './utils/deprecation.js';
 import * as idGenerator from './utils/idgenerator.js';
 import * as parsing from './utils/parsing.js';
+import {replaceMessageReferences} from './utils/parsing.js';
 import {Size} from './utils/size.js';
 import type {Workspace} from './workspace.js';
 
@@ -243,6 +244,9 @@ export class Block {
   inputsInlineDefault?: boolean;
   workspace: Workspace;
 
+  /** A custom provider for generating the aria role description for this block. */
+  private ariaRoleDescriptionProvider: string | (() => string) | undefined;
+
   /**
    * @param workspace The block's workspace.
    * @param prototypeName Name of the language object containing type-specific
@@ -1548,6 +1552,32 @@ export class Block {
     }
   }
 
+  /**
+   * Set a custom aria role description provider for this block. If not set,
+   * uses a default provider based on the block's properties (e.g. whether it has
+   * inputs, outputs, etc.).
+   *
+   * @param description The description or function to provide the description.
+   *   If a string, we'll replace message references in the string, e.g.
+   *   `%{BKY_CUSTOM_MESSAGE}` will be replaced with the value of
+   *   `Blockly.Msg['CUSTOM_MESSAGE']`.}'
+   */
+  setAriaRoleDescriptionProvider(description: string | (() => string)) {
+    this.ariaRoleDescriptionProvider = description;
+  }
+
+  /**
+   * @returns The custom string to use as the role description for this block,
+   *   or undefined if no custom description is set.
+   */
+  getAriaRoleDescription(): string | undefined {
+    if (!this.ariaRoleDescriptionProvider) return undefined;
+    if (typeof this.ariaRoleDescriptionProvider === 'function') {
+      return this.ariaRoleDescriptionProvider();
+    }
+    return replaceMessageReferences(this.ariaRoleDescriptionProvider);
+  }
+
   /**
    * Create a human-readable text representation of this block and any children.
    *
@@ -1802,6 +1832,11 @@ export class Block {
       const localizedValue = parsing.replaceMessageReferences(rawValue);
       this.setHelpUrl(localizedValue);
     }
+
+    if (json['ariaRoleDescription'] !== undefined) {
+      this.setAriaRoleDescriptionProvider(json['ariaRoleDescription']);
+    }
+
     if (typeof json['extensions'] === 'string') {
       console.warn(
         warningPrefix +

packages/blockly/core/block_aria_composer.ts

@@ -87,13 +87,17 @@ export function configureAriaRole(block: BlockSvg) {
     setRole(focusableElement, Role.FIGURE);
   }
 
-  let roleDescription = Msg['BLOCK_LABEL_STATEMENT'];
-  if (block.statementInputCount) {
+  let roleDescription;
+  const customDescription = block.getAriaRoleDescription();
+  if (customDescription) {
+    roleDescription = customDescription;
+  } else if (block.statementInputCount) {
     roleDescription = Msg['BLOCK_LABEL_CONTAINER'];
   } else if (block.outputConnection) {
     roleDescription = Msg['BLOCK_LABEL_VALUE'];
+  } else {
+    roleDescription = Msg['BLOCK_LABEL_STATEMENT'];
   }
-
   setState(focusableElement, State.ROLEDESCRIPTION, roleDescription);
 }
 

packages/blockly/core/interfaces/i_json_block_definition.ts

@@ -42,6 +42,7 @@ export interface JsonBlockDefinition {
   inputsInline?: boolean;
   tooltip?: string;
   helpUrl?: string;
+  ariaRoleDescription?: string;
   extensions?: string[];
   mutator?: string;
   enableContextMenu?: boolean;

packages/blockly/msg/json/en.json

@@ -1,7 +1,7 @@
 {
 	"@metadata": {
 		"author": "Ellen Spertus <ellen.spertus@gmail.com>",
-		"lastupdated": "2026-04-29 12:42:30.774691",
+		"lastupdated": "2026-04-29 16:09:43.926632",
 		"locale": "en",
 		"messagedocumentation" : "qqq"
 	},
@@ -474,7 +474,7 @@
 	"BLOCK_LABEL_REPLACEABLE": "replaceable",
 	"BLOCK_LABEL_HAS_INPUT": "has input",
 	"BLOCK_LABEL_HAS_INPUTS": "has inputs",
-	"BLOCK_LABEL_STATEMENT": "statement",
+	"BLOCK_LABEL_STATEMENT": "command",
 	"BLOCK_LABEL_CONTAINER": "container",
 	"BLOCK_LABEL_VALUE": "value",
 	"BLOCK_LABEL_STACK_BLOCKS": "%1 stack blocks",

packages/blockly/msg/json/qqq.json

@@ -1,5 +1,5 @@
 {
-		"@metadata": {
+	"@metadata": {
 		"authors": [
 			"Ajeje Brazorf",
 			"Amire80",
@@ -482,7 +482,7 @@
 	"BLOCK_LABEL_REPLACEABLE": "Part of an accessibility label for a block that indicates that it is replaceable, i.e. that it is a shadow block.",
 	"BLOCK_LABEL_HAS_INPUT": "Part of an accessibility label for a block that indicates that it has a single input.",
 	"BLOCK_LABEL_HAS_INPUTS": "Part of an accessibility label for a block that indicates that it has more than one input.",
-	"BLOCK_LABEL_STATEMENT": "Part of an accessibility label for a block that indicates that it is a statement block, i.e. that it has a next or previous connection.",
+	"BLOCK_LABEL_STATEMENT": "Part of an accessibility label for a block that indicates that it is a statement block, i.e. that it has a next or previous connection. 'command' here is used in the sense of a computer command, or a command block in Scratch.",
 	"BLOCK_LABEL_CONTAINER": "Part of an accessibility label for a block that indicates that it is a container block, i.e. that it has one or more statement inputs.",
 	"BLOCK_LABEL_VALUE": "Part of an accessibility label for a block that indicates that it is a value block, i.e. that it has an output connection.",
 	"BLOCK_LABEL_STACK_BLOCKS": "Accessibility label for a block that indicates it is a stack of two or more blocks.",

packages/blockly/msg/messages.js

@@ -1880,7 +1880,9 @@ Blockly.Msg.BLOCK_LABEL_HAS_INPUTS = 'has inputs';
 /** @type {string} */
 /// Part of an accessibility label for a block that indicates that it is
 /// a statement block, i.e. that it has a next or previous connection.
-Blockly.Msg.BLOCK_LABEL_STATEMENT = 'statement';
+/// "command" here is used in the sense of a computer command, or a 
+/// command block in Scratch.
+Blockly.Msg.BLOCK_LABEL_STATEMENT = 'command';
 /** @type {string} */
 /// Part of an accessibility label for a block that indicates that it is
 /// a container block, i.e. that it has one or more statement inputs.

packages/blockly/tests/mocha/aria_test.js

@@ -295,7 +295,7 @@ suite('ARIA', function () {
         block.getFocusableElement(),
         Blockly.utils.aria.State.ROLEDESCRIPTION,
       );
-      assert.equal(roleDescription, 'statement');
+      assert.equal(roleDescription, 'command');
     });
 
     test('Value blocks have correct role description', function () {

packages/blockly/tests/mocha/block_json_test.js

@@ -774,4 +774,36 @@ suite('Block JSON initialization', function () {
       });
     });
   });
+  suite('blockFromJson', function () {
+    test('Custom aria role description', function () {
+      const testBlockDefinition = {
+        'type': 'test_block',
+        'ariaRoleDescription': 'Custom aria description',
+      };
+      Blockly.common.defineBlocksWithJsonArray([testBlockDefinition]);
+      const block = this.workspace.newBlock('test_block');
+      assert.equal(
+        block.getAriaRoleDescription(),
+        'Custom aria description',
+        'Expected getAriaRoleDescription to return the custom description.',
+      );
+      delete Blockly.Blocks['test_block'];
+    });
+    test('Custom aria role description with message reference', function () {
+      const testBlockDefinition = {
+        'type': 'test_block',
+        'ariaRoleDescription': '%{BKY_CUSTOM_ROLE_DESCRIPTION}',
+      };
+      Blockly.Msg['CUSTOM_ROLE_DESCRIPTION'] = 'Custom aria description';
+      Blockly.common.defineBlocksWithJsonArray([testBlockDefinition]);
+      const block = this.workspace.newBlock('test_block');
+      assert.equal(
+        block.getAriaRoleDescription(),
+        'Custom aria description',
+        'Expected getAriaRoleDescription to return the custom description.',
+      );
+      delete Blockly.Blocks['test_block'];
+      delete Blockly.Msg['CUSTOM_ROLE_DESCRIPTION'];
+    });
+  });
 });