diff --git a/ops/NEXT.md b/ops/NEXT.md
index 7b172248..944480c7 100644
--- a/ops/NEXT.md
+++ b/ops/NEXT.md
@@ -1,49 +1,73 @@
-# NEXT — Gate 3: Build the work package consumer
+# NEXT — Consumer validates files_in_scope paths exist
 
-**Scope:** Gate 3 — close the Garden's loop. CODE task, SDK-side. The picker EMITS a work package (sdk/src/backlog-picker.ts + testdata/backlog-picker.flow.yaml, merged, four tested properties) and NOTHING consumes it — that is the missing half. Build the consumer: an SDK entrypoint taking an emitted package and turning it into something runnable, validating it has a title, a non-empty scope and a definition of done, and REFUSING with a typed reason when it does not, because a package that cannot be verified must not become work. NOTE: two previous attempts (ee5c9b3e, 06c0d6ab) did this correctly and their files were LOST before delivery by a platform fault — the build sandbox's .git points at a directory that does not exist, so writes cannot be captured. You are not duplicating live work.
+## Target scope (from gate 3)
 
-## Objective
+**Scope:** Harden the Garden's loop with a case it does not yet handle. CODE task, SDK-side.
+
+On main now, all merged and tested:
+  - `sdk/src/backlog-picker.ts` — proposes a work package from ops/BACKLOG.md
+  - `sdk/src/work-package-consumer.ts` — judges one, refusing with a typed
+    reason (missing_title / missing_scope / missing_definition_of_done)
+  - `testdata/backlog-picker.flow.yaml` — the flow, with its canonical spec
+  - a test running the flow's real emit-package output through the consumer,
+    proving the two halves interoperate in both directions
+
+So propose -> judge -> accept/refuse works end to end. What it does NOT do is
+survive a hostile or malformed backlog. Pick ONE of these and do it properly:
+
+  (a) The picker reads whatever ops/BACKLOG.md contains. A malformed entry — a
+      bold title with no body, an unterminated backtick, a bullet nested under
+      another — should produce a typed refusal, never a crash and never a
+      half-formed package. Add the handling and the tests.
 
-Build the SDK entrypoint that takes an emitted work package and turns it into something runnable. The consumer must validate that the package has:
-- A title (non-empty string)
-- A non-empty scope
-- A definition of done
+  (b) The consumer accepts any package whose fields are present. It does not
+      check that files_in_scope names paths that EXIST, so a package can be
+      accepted while scoping files that are not there. Add that check as a new
+      typed refusal reason, with tests.
+
+**Decision:** Implementing option (b) — files_in_scope path existence validation.
+
+## Objective
 
-When any of these is missing or invalid, the consumer REFUSES with a typed reason. A package that cannot be verified must not become work.
+Add a new refusal reason to `work-package-consumer.ts` that rejects packages
+scoping nonexistent files. A package accepted today while naming files that do
+not exist (`sdk/src/does-not-exist.ts`) must be refused with a typed reason
+(`nonexistent_files`).
 
 ## Files in scope
 
-- `sdk/src/` (new consumer code)
-- `sdk/tests/` (new consumer tests)
-- NO changes to `kernel/` (PR #19 is open)
-- NO changes to `sdk/src/demo-hn-monitor.ts` (PR #19 is open)
+- `sdk/src/work-package-consumer.ts`
+- `sdk/tests/work-package-consumer.test.ts`
+- `sdk/src/index.ts` (if new types need export)
 
 ## Definition of done
 
-1. **SDK code exists** that consumes an emitted work package
-2. **Validation tests exist** for:
-   - Missing title → typed refusal
-   - Empty title → typed refusal
-   - Missing scope → typed refusal
-   - Empty scope → typed refusal
-   - Missing definition of done → typed refusal
-   - Empty definition of done → typed refusal
-   - Valid package → accepted
-3. **Every new test is confirmed to FAIL against current code** with literal output pasted
-4. **SDK test suite passes:**
+1. **New typed refusal reason** `nonexistent_files` added to
+   `WorkPackageRefusalReason` type
+2. **Path existence check** in `consumeWorkPackage` that refuses when
+   files_in_scope contains paths that do not exist on disk
+3. **Tests covering the new behavior:**
+   - Test: refuse a package with all nonexistent files
+   - Test: refuse a package with a mix of existent and nonexistent files
+   - Test: accept a package with all existent files
+4. **EVERY new test confirmed to FAIL against current code** — the literal
+   failing output must be quoted below when reporting BUILD_DONE
+5. **Existing tests still passing** — all 8 existing work-package-consumer tests
+   green
+6. **Full SDK suite passing:**
    ```
    cd sdk && npm test
    ```
-   Paste the literal output showing all tests pass, 0 failed
-5. **Final verification** — as the LAST action, run:
+   Must show green suite with exact pass count.
+7. **As the LAST action, run and paste:**
    ```
    git status --porcelain
    ```
-   And paste the output to make lost writes visible immediately
 
 ## Out of scope
 
-- Kernel changes (different PR)
-- Integration with hn-monitor (different PR)
-- Any changes to the backlog picker itself (already merged in PRs #20, #21, #22)
-- Changes to flow execution or scheduling
+- Picker malformed-entry handling (option a) — that is NOT this run's target
+- Checking that files are readable, only that they exist
+- Recursively resolving directory globs — check the literal path only
+- Any changes to kernel/, testdata/, or ops/
+- Any changes to sdk/src/demo-hn-monitor.ts
diff --git a/sdk/src/work-package-consumer.ts b/sdk/src/work-package-consumer.ts
index 1611a1b7..7bceac47 100644
--- a/sdk/src/work-package-consumer.ts
+++ b/sdk/src/work-package-consumer.ts
@@ -1,3 +1,6 @@
+import { existsSync } from 'node:fs';
+import { fileURLToPath } from 'node:url';
+
 /** The work-package shape emitted at the SDK boundary. */
 export interface EmittedWorkPackage {
   title: string;
@@ -10,7 +13,8 @@ export interface EmittedWorkPackage {
 export type WorkPackageRefusalReason =
   | 'missing_title'
   | 'missing_scope'
-  | 'missing_definition_of_done';
+  | 'missing_definition_of_done'
+  | 'nonexistent_files';
 
 export type WorkPackageConsumption =
   | { accepted: true; work: EmittedWorkPackage }
@@ -30,9 +34,18 @@ export function consumeWorkPackage(input: unknown): WorkPackageConsumption {
   if (!isNonEmptyStringArray(input['definition_of_done'])) {
     return { accepted: false, reason: 'missing_definition_of_done' };
   }
+  if (!input['files_in_scope'].every(pathExists)) {
+    return { accepted: false, reason: 'nonexistent_files' };
+  }
   return { accepted: true, work: input as unknown as EmittedWorkPackage };
 }
 
+const repositoryRoot = new URL('../../', import.meta.url);
+
+function pathExists(path: string): boolean {
+  return existsSync(fileURLToPath(new URL(path, repositoryRoot)));
+}
+
 function isRecord(value: unknown): value is Record<string, unknown> {
   return typeof value === 'object' && value !== null && !Array.isArray(value);
 }
diff --git a/sdk/tests/work-package-consumer.test.ts b/sdk/tests/work-package-consumer.test.ts
index 4b8d4884..120952f2 100644
--- a/sdk/tests/work-package-consumer.test.ts
+++ b/sdk/tests/work-package-consumer.test.ts
@@ -55,6 +55,29 @@ describe('work package consumer', () => {
   it('accepts a valid package as runnable work', async () => {
     expect(await consume(validPackage)).toEqual({ accepted: true, work: validPackage });
   });
+
+  it('refuses a package when all files in scope are nonexistent', async () => {
+    expect(
+      await consume({ ...validPackage, files_in_scope: ['sdk/src/does-not-exist.ts'] }),
+    ).toEqual({ accepted: false, reason: 'nonexistent_files' });
+  });
+
+  it('refuses a package when some files in scope are nonexistent', async () => {
+    expect(
+      await consume({
+        ...validPackage,
+        files_in_scope: ['sdk/src/work-package-consumer.ts', 'sdk/src/does-not-exist.ts'],
+      }),
+    ).toEqual({ accepted: false, reason: 'nonexistent_files' });
+  });
+
+  it('accepts a package when all files in scope exist', async () => {
+    const input = {
+      ...validPackage,
+      files_in_scope: ['sdk/src/work-package-consumer.ts', 'sdk/tests/'],
+    };
+    expect(await consume(input)).toEqual({ accepted: true, work: input });
+  });
 });
 
 describe('the Garden join: picker output feeds the consumer', () => {
@@ -83,7 +106,7 @@ describe('the Garden join: picker output feeds the consumer', () => {
       // An entry carrying a runnable command: that IS its definition of done.
       writeFileSync(
         join(dir, 'ops', 'BACKLOG.md'),
-        '# Backlog\n\n- **Actionable entry** touches `sdk/src/x.ts`, verified by `npm test --silent`\n',
+        '# Backlog\n\n- **Actionable entry** touches `sdk/src/work-package-consumer.ts`, verified by `npm test --silent`\n',
       );
       run(step('read-backlog'), dir);
       run(step('select-entry'), dir);