diff --git a/tools/spectral/ipa/README.md b/tools/spectral/ipa/README.md
index e317e5d5a9..55814340ed 100644
--- a/tools/spectral/ipa/README.md
+++ b/tools/spectral/ipa/README.md
@@ -76,6 +76,42 @@ overrides:
          x-xgen-IPA-xxx-rule: 'off'
 ```
 
+#### Consumer-Provided Word Lists
+
+The casing rules `xgen-IPA-117-operation-summary-format` and `xgen-IPA-126-tag-names-should-use-title-case`
+use two configurable lists:
+
+- `ignoreList`: words allowed to keep their specific casing (e.g. acronyms such as `API`, `AWS`, `DNS`)
+- `grammaticalWords`: common words allowed to stay lowercase in titles (e.g. `and`, `or`, `the`)
+
+Both lists are passed to the rule functions through Spectral's native `functionOptions`. Consumers who
+extend the ruleset can provide their own lists by redeclaring the rule in their `.spectral.yaml`, without
+editing this package or waiting for a new release:
+
+```yaml
+extends:
+  - '@mongodb/ipa-validation-ruleset'
+
+rules:
+  xgen-IPA-126-tag-names-should-use-title-case:
+    given: $.tags[?(@.name && @.name.length > 0)]
+    then:
+      function: IPA126TagNamesShouldUseTitleCase
+      functionOptions:
+        ignoreList:
+          - API
+          - AWS
+          # ...the words this repository needs
+        grammaticalWords:
+          - and
+          - or
+```
+
+Because Spectral requires the whole rule to be redeclared when overriding `functionOptions`, consumers own
+the complete lists for their repository. The lists defined in `IPA-117.yaml` and `IPA-126.yaml` remain the
+canonical package defaults and are the ones used by this repository's own CI, so validation here is
+unaffected by any consumer overrides.
+
 ### CI/CD Integration
 
 #### GitHub Actions Example
diff --git a/tools/spectral/ipa/__tests__/ConsumerWordLists.test.js b/tools/spectral/ipa/__tests__/ConsumerWordLists.test.js
new file mode 100644
index 0000000000..ccee34ed1b
--- /dev/null
+++ b/tools/spectral/ipa/__tests__/ConsumerWordLists.test.js
@@ -0,0 +1,73 @@
+import { describe, expect, it } from '@jest/globals';
+import * as fs from 'node:fs';
+import * as path from 'node:path';
+import { Spectral } from '@stoplight/spectral-core';
+import { httpAndFileResolver } from '@stoplight/spectral-ref-resolver';
+import { bundleAndLoadRuleset } from '@stoplight/spectral-ruleset-bundler/with-loader';
+
+// Proof that consumers extending the ruleset can supply their own `ignoreList` and
+// `grammaticalWords` by redeclaring the rule with their own `functionOptions` — the
+// native Spectral mechanism — without editing this package. The lists in the shipped
+// rulesets remain the canonical defaults used by this repository's own CI.
+async function runRuleWithOptions(ruleName, rulesetFile, functionOptions, document) {
+  const rulesetPath = path.join(__dirname, '../rulesets', rulesetFile);
+  const s = new Spectral({ resolver: httpAndFileResolver });
+  const ruleset = Object(await bundleAndLoadRuleset(rulesetPath, { fs, fetch })).toJSON();
+  const definition = ruleset.rules[ruleName].definition;
+  if (functionOptions) {
+    definition.then.functionOptions = functionOptions;
+  }
+  const scopedRuleset = { rules: { [ruleName]: definition } };
+  if (ruleset.aliases) {
+    scopedRuleset.aliases = ruleset.aliases;
+  }
+  s.setRuleset(scopedRuleset);
+  return s.run(JSON.stringify(document));
+}
+
+describe('Consumer-provided word lists via functionOptions', () => {
+  describe('xgen-IPA-126-tag-names-should-use-title-case (ignoreList)', () => {
+    const document = { tags: [{ name: 'ACME Alerts' }] };
+
+    it('flags a consumer acronym that is not in the package ignoreList', async () => {
+      const errors = await runRuleWithOptions(
+        'xgen-IPA-126-tag-names-should-use-title-case',
+        'IPA-126.yaml',
+        null,
+        document
+      );
+      expect(errors).toHaveLength(1);
+      expect(errors[0].code).toEqual('xgen-IPA-126-tag-names-should-use-title-case');
+    });
+
+    it('accepts the consumer acronym once added to functionOptions', async () => {
+      const errors = await runRuleWithOptions(
+        'xgen-IPA-126-tag-names-should-use-title-case',
+        'IPA-126.yaml',
+        { ignoreList: ['ACME'], grammaticalWords: [] },
+        document
+      );
+      expect(errors).toHaveLength(0);
+    });
+  });
+
+  describe('xgen-IPA-117-operation-summary-format (grammaticalWords)', () => {
+    const document = { paths: { '/resource': { get: { summary: 'Return One Resource per Project' } } } };
+
+    it('flags a consumer grammatical word that is not in the package list', async () => {
+      const errors = await runRuleWithOptions('xgen-IPA-117-operation-summary-format', 'IPA-117.yaml', null, document);
+      expect(errors).toHaveLength(1);
+      expect(errors[0].code).toEqual('xgen-IPA-117-operation-summary-format');
+    });
+
+    it('accepts the consumer grammatical word once added to functionOptions', async () => {
+      const errors = await runRuleWithOptions(
+        'xgen-IPA-117-operation-summary-format',
+        'IPA-117.yaml',
+        { ignoreList: [], grammaticalWords: ['per'] },
+        document
+      );
+      expect(errors).toHaveLength(0);
+    });
+  });
+});