diff --git a/packages/jsii-pacmak/bin/jsii-pacmak.ts b/packages/jsii-pacmak/bin/jsii-pacmak.ts
index dbb02105aa..35f39df32d 100644
--- a/packages/jsii-pacmak/bin/jsii-pacmak.ts
+++ b/packages/jsii-pacmak/bin/jsii-pacmak.ts
@@ -1,6 +1,7 @@
 #!/usr/bin/env node
 import '@jsii/check-node/run';
 
+import { UnknownSnippetMode } from 'jsii-rosetta';
 import * as yargs from 'yargs';
 
 import { pacmak, configureLogging, TargetName } from '../lib';
@@ -93,9 +94,20 @@ import { VERSION_DESC } from '../lib/version';
     })
     .option('rosetta-translate-live', {
       type: 'boolean',
-      desc: "Translate code samples on-the-fly if they can't be found in the samples tablet",
+      desc: "Translate code samples on-the-fly if they can't be found in the samples tablet (deprecated)",
       default: true,
     })
+    .option('rosetta-unknown-snippets', {
+      type: 'string',
+      requiresArg: true,
+      optional: true,
+      choices: [
+        UnknownSnippetMode.VERBATIM,
+        UnknownSnippetMode.TRANSLATE,
+        UnknownSnippetMode.FAIL,
+      ],
+      desc: "What to do with code samples if they can't be found in the samples tablet",
+    })
     .option('parallel', {
       type: 'boolean',
       desc: 'Generate all configured targets in parallel (disabling this might help if you encounter EMFILE errors)',
@@ -136,6 +148,9 @@ import { VERSION_DESC } from '../lib/version';
     parallel: argv.parallel,
     recurse: argv.recurse,
     rosettaLiveConversion: argv['rosetta-translate-live'],
+    rosettaUnknownSnippets: argv['rosetta-unknown-snippets'] as
+      | UnknownSnippetMode
+      | undefined,
     rosettaTablet: argv['rosetta-tablet'],
     targets: argv.targets?.map((target) => target as TargetName),
     updateNpmIgnoreFiles: argv.npmignore,
diff --git a/packages/jsii-pacmak/lib/index.ts b/packages/jsii-pacmak/lib/index.ts
index c953c53502..29098cf533 100644
--- a/packages/jsii-pacmak/lib/index.ts
+++ b/packages/jsii-pacmak/lib/index.ts
@@ -1,5 +1,5 @@
 import { TypeSystem } from 'jsii-reflect';
-import { Rosetta } from 'jsii-rosetta';
+import { Rosetta, UnknownSnippetMode } from 'jsii-rosetta';
 
 import * as logging from './logging';
 import { findJsiiModules, updateAllNpmIgnores } from './npm-modules';
@@ -31,10 +31,17 @@ export async function pacmak({
   rosettaTablet,
   targets = Object.values(TargetName),
   timers = new Timers(),
+  rosettaUnknownSnippets = undefined,
   updateNpmIgnoreFiles = false,
   validateAssemblies = false,
 }: PacmakOptions): Promise<void> {
-  const rosetta = new Rosetta({ liveConversion: rosettaLiveConversion });
+  const unknownSnippets =
+    rosettaUnknownSnippets ??
+    (rosettaLiveConversion
+      ? UnknownSnippetMode.TRANSLATE
+      : UnknownSnippetMode.VERBATIM);
+
+  const rosetta = new Rosetta({ unknownSnippets });
   if (rosettaTablet) {
     await rosetta.loadTabletFromFile(rosettaTablet);
   }
@@ -219,9 +226,17 @@ export interface PacmakOptions {
    * already translated in the `rosettaTablet` file.
    *
    * @default false
+   * @deprecated Use `rosettaUnknownSnippets` instead.
    */
   readonly rosettaLiveConversion?: boolean;
 
+  /**
+   * How rosetta should treat snippets that cannot be loaded from a translation tablet.
+   *
+   * @default - falls back to the default of `rosettaLiveConversion`.
+   */
+  readonly rosettaUnknownSnippets?: UnknownSnippetMode;
+
   /**
    * A Rosetta tablet file where translations for code examples can be found.
    *
diff --git a/packages/jsii-rosetta/lib/commands/transliterate.ts b/packages/jsii-rosetta/lib/commands/transliterate.ts
index 23432d9c31..082c5a85f5 100644
--- a/packages/jsii-rosetta/lib/commands/transliterate.ts
+++ b/packages/jsii-rosetta/lib/commands/transliterate.ts
@@ -5,7 +5,7 @@ import { resolve } from 'path';
 import { fixturize } from '../fixtures';
 import { TargetLanguage } from '../languages';
 import { debug } from '../logging';
-import { Rosetta } from '../rosetta';
+import { Rosetta, UnknownSnippetMode } from '../rosetta';
 import { SnippetParameters, typeScriptSnippetFromSource, ApiLocation } from '../snippet';
 import { Translation } from '../tablets/tablets';
 
@@ -53,7 +53,7 @@ export async function transliterateAssembly(
 ): Promise<void> {
   const rosetta = new Rosetta({
     includeCompilerDiagnostics: true,
-    liveConversion: true,
+    unknownSnippets: UnknownSnippetMode.TRANSLATE,
     loose: options.loose,
     targetLanguages,
   });
diff --git a/packages/jsii-rosetta/lib/rosetta.ts b/packages/jsii-rosetta/lib/rosetta.ts
index babacb94ec..77e60f7c02 100644
--- a/packages/jsii-rosetta/lib/rosetta.ts
+++ b/packages/jsii-rosetta/lib/rosetta.ts
@@ -17,17 +17,35 @@ import {
   ApiLocation,
   typeScriptSnippetFromSource,
 } from './snippet';
+import { snippetKey } from './tablets/key';
 import { DEFAULT_TABLET_NAME, LanguageTablet, Translation } from './tablets/tablets';
 import { Translator } from './translate';
 import { printDiagnostics } from './util';
 
+export enum UnknownSnippetMode {
+  /**
+   * Return the snippet as given (untranslated)
+   */
+  VERBATIM = 'verbatim',
+
+  /**
+   * Live-translate the snippet as best as we can
+   */
+  TRANSLATE = 'translate',
+
+  /**
+   * Throw an error if this occurs
+   */
+  FAIL = 'fail',
+}
+
 export interface RosettaOptions {
   /**
    * Whether or not to live-convert samples
    *
-   * @default false
+   * @default UnknownSnippetMode.VERBATIM
    */
-  readonly liveConversion?: boolean;
+  readonly unknownSnippets?: UnknownSnippetMode;
 
   /**
    * Target languages to use for live conversion
@@ -75,9 +93,11 @@ export class Rosetta {
   private readonly extractedSnippets = new Map<string, TypeScriptSnippet>();
   private readonly translator: Translator;
   private readonly loose: boolean;
+  private readonly unknownSnippets: UnknownSnippetMode;
 
   public constructor(private readonly options: RosettaOptions = {}) {
     this.loose = !!options.loose;
+    this.unknownSnippets = options.unknownSnippets ?? UnknownSnippetMode.VERBATIM;
     this.translator = new Translator(options.includeCompilerDiagnostics ?? false);
   }
 
@@ -115,7 +135,7 @@ export class Rosetta {
    *
    * Otherwise, if live conversion is enabled, the snippets in the assembly
    * become available for live translation later. This is necessary because we probably
-   * need to fixture snippets for successful compilation, and the information
+   * need to fixturize snippets for successful compilation, and the information
    * pacmak sends our way later on is not going to be enough to do that.
    */
   public async addAssembly(assembly: spec.Assembly, assemblyDir: string) {
@@ -129,9 +149,11 @@ export class Rosetta {
       }
     }
 
-    if (this.options.liveConversion) {
+    // Inventarize the snippets from this assembly, but only if there's a chance
+    // we're going to need them.
+    if (this.unknownSnippets === UnknownSnippetMode.TRANSLATE) {
       for (const tsnip of allTypeScriptSnippets([{ assembly, directory: assemblyDir }], this.loose)) {
-        this.extractedSnippets.set(tsnip.visibleSource, tsnip);
+        this.extractedSnippets.set(snippetKey(tsnip), tsnip);
       }
     }
   }
@@ -147,9 +169,16 @@ export class Rosetta {
    *   will be based on the snippet key, which consists of a hash of the
    *   visible source and the API location.
    * - Otherwise, translate the snippet as-is (without fixture information).
+   *
+   * This will do and store a full conversion of the given snippet, even if it only
+   * returns one language. Subsequent retrievals for the same snippet in other
+   * languages will reuse the translation from cache.
+   *
+   * If you are calling this for the side effect of adding translations to the live
+   * tablet, you only need to do that for one language.
    */
   public translateSnippet(source: TypeScriptSnippet, targetLang: TargetLanguage): Translation | undefined {
-    // Look for it in loaded tablets
+    // Look for it in loaded tablets (or previous conversions)
     for (const tab of this.allTablets) {
       const ret = tab.lookup(source, targetLang);
       if (ret !== undefined) {
@@ -157,9 +186,23 @@ export class Rosetta {
       }
     }
 
-    if (!this.options.liveConversion) {
-      return undefined;
+    if (this.unknownSnippets === UnknownSnippetMode.VERBATIM) {
+      return {
+        language: targetLang,
+        source: source.visibleSource,
+      };
+    }
+
+    if (this.unknownSnippets === UnknownSnippetMode.FAIL) {
+      const message = [
+        'The following snippet was not found in any of the loaded tablets:',
+        source.visibleSource,
+        `Location: ${JSON.stringify(source.location)}`,
+        `Language: ${targetLang}`,
+      ].join('\n');
+      throw new Error(message);
     }
+
     if (this.options.targetLanguages && !this.options.targetLanguages.includes(targetLang)) {
       throw new Error(
         `Rosetta configured for live conversion to ${this.options.targetLanguages.join(
@@ -168,15 +211,16 @@ export class Rosetta {
       );
     }
 
-    // See if we're going to live-convert it with full source information
-    const extracted = this.extractedSnippets.get(source.visibleSource);
+    // See if we can find a fixturized version of this snippet. If so, use that do the live
+    // conversion.
+    const extracted = this.extractedSnippets.get(snippetKey(source));
     if (extracted !== undefined) {
       const snippet = this.translator.translate(extracted, this.options.targetLanguages);
       this.liveTablet.addSnippet(snippet);
       return snippet.get(targetLang);
     }
 
-    // Try to live-convert it on the spot (we won't have "where" information or fixtures)
+    // Try to live-convert it as-is.
     const snippet = this.translator.translate(source, this.options.targetLanguages);
     this.liveTablet.addSnippet(snippet);
     return snippet.get(targetLang);
diff --git a/packages/jsii-rosetta/test/rosetta.test.ts b/packages/jsii-rosetta/test/rosetta.test.ts
index a2d58e332a..596037eaa6 100644
--- a/packages/jsii-rosetta/test/rosetta.test.ts
+++ b/packages/jsii-rosetta/test/rosetta.test.ts
@@ -7,6 +7,7 @@ import {
   TypeScriptSnippet,
   DEFAULT_TABLET_NAME,
   Translation,
+  UnknownSnippetMode,
 } from '../lib';
 import { TargetLanguage } from '../lib/languages';
 import { fakeAssembly } from './jsii/fake-assembly';
@@ -23,7 +24,7 @@ describe('Rosetta object can do live translation', () => {
   beforeEach(() => {
     // GIVEN
     rosetta = new Rosetta({
-      liveConversion: true,
+      unknownSnippets: UnknownSnippetMode.TRANSLATE,
       targetLanguages: [TargetLanguage.PYTHON],
     });
 
@@ -70,7 +71,7 @@ test('Can use preloaded tablet', () => {
 test('Rosetta object can do live translation', () => {
   // GIVEN
   const rosetta = new Rosetta({
-    liveConversion: true,
+    unknownSnippets: UnknownSnippetMode.TRANSLATE,
     targetLanguages: [TargetLanguage.PYTHON],
   });
 
@@ -84,10 +85,36 @@ test('Rosetta object can do live translation', () => {
   });
 });
 
+test('Rosetta object can fail on untranslated snippet', () => {
+  // GIVEN
+  const rosetta = new Rosetta({
+    unknownSnippets: UnknownSnippetMode.FAIL,
+    targetLanguages: [TargetLanguage.PYTHON],
+  });
+
+  // WHEN
+  expect(() => {
+    rosetta.translateSnippet(SAMPLE_CODE, TargetLanguage.PYTHON);
+  }).toThrow(/snippet was not found/);
+});
+
+test('Rosetta can give you an untranslated snippet back', () => {
+  // GIVEN
+  const rosetta = new Rosetta({
+    unknownSnippets: UnknownSnippetMode.VERBATIM,
+    targetLanguages: [TargetLanguage.PYTHON],
+  });
+
+  // WHEN
+  const translated = rosetta.translateSnippet(SAMPLE_CODE, TargetLanguage.PYTHON);
+
+  expect(translated?.source).toEqual('callThisFunction();');
+});
+
 test('Rosetta object can do translation and annotation of snippets in MarkDown', () => {
   // GIVEN
   const rosetta = new Rosetta({
-    liveConversion: true,
+    unknownSnippets: UnknownSnippetMode.TRANSLATE,
     targetLanguages: [TargetLanguage.PYTHON],
   });