Fix trim:false to disable runtime trimming

Author: PredictabilityAtScale

src/context.ts

@@ -58,6 +58,10 @@ export function normalizeContextInput(input: ContextInputDefinition): Normalized
 
 type TrimMode = boolean | 'start' | 'end' | 'both';
 
+function isTrimEnabled(mode: TrimMode | undefined): mode is true | 'start' | 'end' | 'both' {
+  return mode === true || mode === 'start' || mode === 'end' || mode === 'both';
+}
+
 function normalizeTrimMode(mode: TrimMode): 'start' | 'end' {
   if (mode === 'start') {
     return 'start';
@@ -135,11 +139,8 @@ export function sanitizeContextVariables(
       }
     }
 
-    if (input.trim !== undefined) {
-      const trimMode = input.trim;
-      if (input.max_size !== undefined) {
-        candidate = trimToMaxSize(candidate, input.max_size, trimMode);
-      }
+    if (isTrimEnabled(input.trim) && input.max_size !== undefined) {
+      candidate = trimToMaxSize(candidate, input.max_size, input.trim);
     }
 
     sanitized[input.name] = candidate;

src/validation/validate.ts

@@ -118,7 +118,7 @@ export function validateAsset(
 
   // Context regex definitions compile successfully
   for (const input of getContextInputs(asset)) {
-    if (input.trim !== undefined && input.max_size === undefined) {
+    if (input.trim !== undefined && input.trim !== false && input.max_size === undefined) {
       warnings.push({
         code: 'POK014',
         message: `Context input "${input.name}" sets trim but has no max_size; trim-to-budget will be skipped.`,

tests/runtime-context-placeholders.test.ts

@@ -338,6 +338,41 @@ Context: {{ app_context }}
     expect(result.warnings).toHaveLength(0);
   });
 
+  it('does not trim when trim is explicitly false and still emits oversize warning', async () => {
+    const sourceDir = join(tmpDir, 'prompts');
+    await mkdir(sourceDir, { recursive: true });
+
+    await writeFile(join(sourceDir, 'untrimmed-context.md'), `---
+id: untrimmed.context
+schema_version: 1
+provider: openai
+model: gpt-5.4
+context:
+  inputs:
+    - name: app_context
+      trim: false
+      max_size: 5
+---
+
+# Prompt template
+
+Context: {{ app_context }}
+`);
+
+    const kit = createPromptOpsKit({ sourceDir, mode: 'source-only', cache: false });
+    const result = await kit.renderPrompt({
+      path: 'untrimmed-context',
+      provider: 'openai',
+      variables: { app_context: 'admin-dashboard' },
+    });
+
+    const messages = result.request.body.messages as Array<{ role: string; content: string }>;
+    expect(messages[0].content).toContain('Context: admin-dashboard');
+    expect(result.warnings).toContain(
+      'POK030: Context variable "app_context" exceeded max_size for prompt "untrimmed.context" (15 bytes > 5 bytes).',
+    );
+  });
+
   it('rejects context variables that fail regex validation', async () => {
     const sourceDir = join(tmpDir, 'prompts');
     await mkdir(sourceDir, { recursive: true });

tests/validation.test.ts

@@ -138,6 +138,20 @@ describe('validateAsset', () => {
     expect(result.warnings.some((warning) => warning.code === 'POK014')).toBe(true);
   });
 
+  it('does not warn when trim is explicitly false without max_size', () => {
+    const result = validateAsset({
+      id: 'test',
+      schema_version: 1,
+      context: {
+        inputs: [{ name: 'user_id', trim: false }],
+      },
+      sections: { prompt_template: '{{ user_id }}' },
+    });
+
+    expect(result.valid).toBe(true);
+    expect(result.warnings.some((warning) => warning.code === 'POK014')).toBe(false);
+  });
+
   it('warns when regex and allow_regex are both set', () => {
     const result = validateAsset({
       id: 'test',