diff --git a/.changeset/apply-surface-deferred-scope.md b/.changeset/apply-surface-deferred-scope.md
new file mode 100644
index 0000000000..daafa643db
--- /dev/null
+++ b/.changeset/apply-surface-deferred-scope.md
@@ -0,0 +1,5 @@
+---
+"@fission-ai/openspec": patch
+---
+
+Apply workflow now tells agents to surface unexpected scope instead of hiding it. When a task needs work beyond what the spec describes, the `/opsx:apply` skill and command guidance direct the agent to pause and report the added scope rather than silently narrowing, deferring, or simplifying away specified behavior, and to mark a task complete only when its specified behavior is fully implemented. Fixes #1529.
diff --git a/skills/openspec-apply-change/SKILL.md b/skills/openspec-apply-change/SKILL.md
index cd00a8b444..e9dc213b6b 100644
--- a/skills/openspec-apply-change/SKILL.md
+++ b/skills/openspec-apply-change/SKILL.md
@@ -99,6 +99,7 @@ Implement tasks from an OpenSpec change.
    **Pause if:**
    - Task is unclear → ask for clarification
    - Implementation reveals a design issue → suggest updating artifacts
+   - A task needs work beyond what the spec and tasks describe, or you are tempted to drop, narrow, defer, or accept exceptions to specified behavior to make it fit → surface the added scope and ask; do not absorb it silently
    - Error or blocker encountered → report and wait for guidance
    - User interrupts
 
@@ -169,6 +170,8 @@ What would you like to do?
 - Keep code changes minimal and scoped to each task
 - Update task checkbox immediately after completing each task
 - Pause on errors, blockers, or unclear requirements - don't guess
+- When a task needs work beyond what the spec describes, surface the added scope and pause - never silently narrow, defer, or simplify away specified behavior
+- Only mark a task `- [x]` when its specified behavior is fully implemented, not when it is partially done or deferred
 - Use contextFiles from CLI output, don't assume specific file names
 - Do not use context or operation guidance as proof that a task is complete
 - Apply relevant project context; report conflicts with controlling workflow inputs
diff --git a/src/core/templates/workflows/apply-change.ts b/src/core/templates/workflows/apply-change.ts
index 931f6e7b68..d7ebe2f4eb 100644
--- a/src/core/templates/workflows/apply-change.ts
+++ b/src/core/templates/workflows/apply-change.ts
@@ -107,6 +107,7 @@ ${STORE_SELECTION_GUIDANCE}
    **Pause if:**
    - Task is unclear → ask for clarification
    - Implementation reveals a design issue → suggest updating artifacts
+   - A task needs work beyond what the spec and tasks describe, or you are tempted to drop, narrow, defer, or accept exceptions to specified behavior to make it fit → surface the added scope and ask; do not absorb it silently
    - Error or blocker encountered → report and wait for guidance
    - User interrupts
 
@@ -177,6 +178,8 @@ What would you like to do?
 - Keep code changes minimal and scoped to each task
 - Update task checkbox immediately after completing each task
 - Pause on errors, blockers, or unclear requirements - don't guess
+- When a task needs work beyond what the spec describes, surface the added scope and pause - never silently narrow, defer, or simplify away specified behavior
+- Only mark a task \`- [x]\` when its specified behavior is fully implemented, not when it is partially done or deferred
 - Use contextFiles from CLI output, don't assume specific file names
 - Do not use context or operation guidance as proof that a task is complete
 - Apply relevant project context; report conflicts with controlling workflow inputs
diff --git a/test/core/templates/apply-defer-guardrail.test.ts b/test/core/templates/apply-defer-guardrail.test.ts
new file mode 100644
index 0000000000..51fc85f340
--- /dev/null
+++ b/test/core/templates/apply-defer-guardrail.test.ts
@@ -0,0 +1,36 @@
+import { describe, it, expect } from 'vitest';
+import {
+  getApplyInstructions,
+  getApplyChangeSkillTemplate,
+  getOpsxApplyCommandTemplate,
+} from '../../../src/core/templates/workflows/apply-change.js';
+
+// #1529: agents were silently simplifying or deferring work mid-apply and
+// marking tasks done anyway. The apply instructions must tell the agent to
+// surface unexpected scope instead of absorbing it, on both surfaces.
+describe('apply instructions surface deferred scope (#1529)', () => {
+  const instructions = getApplyInstructions();
+
+  it('tells the agent to surface added scope rather than defer or simplify', () => {
+    expect(instructions).toContain('surface the added scope');
+    expect(instructions).toContain('beyond what the spec describes');
+    expect(instructions).toMatch(/never silently narrow, defer/);
+  });
+
+  it('requires pausing, not just reporting and continuing', () => {
+    // The agent must hand control back, not surface the scope and press on.
+    expect(instructions).toContain('surface the added scope and pause');
+  });
+
+  it('forbids marking a task complete when it is only partially done', () => {
+    expect(instructions).toMatch(
+      /Only mark a task .* when its specified behavior is fully implemented/
+    );
+  });
+
+  it('carries the same guidance on both the skill and command surfaces', () => {
+    const needle = 'surface the added scope';
+    expect(getApplyChangeSkillTemplate().instructions).toContain(needle);
+    expect(getOpsxApplyCommandTemplate().content).toContain(needle);
+  });
+});
diff --git a/test/core/templates/skill-templates-parity.test.ts b/test/core/templates/skill-templates-parity.test.ts
index e0a1995752..8c267c617a 100644
--- a/test/core/templates/skill-templates-parity.test.ts
+++ b/test/core/templates/skill-templates-parity.test.ts
@@ -41,14 +41,14 @@ const EXPECTED_FUNCTION_HASHES: Record<string, string> = {
   getExploreSkillTemplate: 'fec38ba01c5c20695aca0ec7eff78c26e278ead21459cab8ec1562af51053427',
   getNewChangeSkillTemplate: '935f6335e2d4b7d1bd4f0538c88386350c25e8b16e11b627556262229583ca51',
   getContinueChangeSkillTemplate: 'ed41e2356af7aad6ef760f60fad19c6843cefe436d8f90084dcba4dbc6bf7272',
-  getApplyChangeSkillTemplate: '0de84d3e414c0bc72b21a47384257a1b3bc754336538e245db55af307d7eda99',
+  getApplyChangeSkillTemplate: 'a8d2529741849723ef160726648173e8ca8b42f5bb6f3d89ec547268adce2846',
   getFfChangeSkillTemplate: 'fc2a45a08533ee9c7ab30fdab5f832b7d440070048e2a153f03db1620dc379bb',
   getSyncSpecsSkillTemplate: 'd43b112a3c74bc951b094d220c8e75cca26bb00640d404b78af0752af1ff7bd9',
   getOnboardSkillTemplate: 'a9f6134b187ec4f3a5aa6c7c181e51a15fec11b7ac1044a076fdfe79b47fbc80',
   getOpsxExploreCommandTemplate: 'e2d470148708a9070675edddd1e783f1c71c96625d08cff4fe7a9994e0d292c0',
   getOpsxNewCommandTemplate: '08e784e52ac2c146975a874257c589d88e93efbd83dc4d79253c8525f5c3064f',
   getOpsxContinueCommandTemplate: 'ae964cd00f6ca332fd7f9428a577ade75be279f50431d5f60ece8172e8d1a4b1',
-  getOpsxApplyCommandTemplate: 'd27ad905657dd3797571eccee2b6416495fa9b39759d36b43a9871a301757979',
+  getOpsxApplyCommandTemplate: '860b55e4ffc055bb6f7339eeb65eaa695e09be7738dff2260726403647a57a18',
   getOpsxFfCommandTemplate: '012610f85576a7055dfec2aaabba6bfc245454ce91fb6214587ae9316dc2b864',
   getArchiveChangeSkillTemplate: '5ef19163f73997fdda1c69dc8bca710c16c50b052b481821d916f4084bb42a64',
   getBulkArchiveChangeSkillTemplate: '03cc44a0ce9bdb3ba2668a9d43946596308901600aa29a728c4a71fc76e86de3',
@@ -69,7 +69,7 @@ const EXPECTED_GENERATED_SKILL_CONTENT_HASHES: Record<string, string> = {
   'openspec-explore': '80109dec3abf1505ab1037f7196baac4fcdf175ca954411e8d439e5da881bf62',
   'openspec-new-change': '579d432771703f947a331a6ed288bf9c6660ca015fcd376d76f19b6ac7683082',
   'openspec-continue-change': '5c34be8194cdb4c5158335e47aece71143e8a22bfb4179dba47fd8aaf436d395',
-  'openspec-apply-change': 'a1c79d1104255f7655df120d3ebf362cc14a2bb23ae6e857ba430dea2f8bc8bc',
+  'openspec-apply-change': '2709759f101b455dbd93779005f6692966a37c7c71336af9dc5752906046d4f8',
   'openspec-ff-change': '19315644df7c582d920acfb67f3c500ca4e06fccc900265b3ac39621d85f7cdb',
   'openspec-sync-specs': '6e85521de10858bb020885eb657aa843e5746b2f09c846aa44545694f456cda9',
   'openspec-archive-change': '019d580a13eee5892cc9233a899919b572a3abfc6a05c1f0aabf9c4ba9bf3d4d',