diff --git a/.changeset/embedded-action-crossref-validation.md b/.changeset/embedded-action-crossref-validation.md
new file mode 100644
index 0000000000..ff7a4a7890
--- /dev/null
+++ b/.changeset/embedded-action-crossref-validation.md
@@ -0,0 +1,59 @@
+---
+"@objectstack/spec": minor
+---
+
+fix(spec): `defineStack`'s action cross-reference walk now reaches OBJECT-EMBEDDED actions (#7397)
+
+The same defect as #6889, one authoring position over. `validateCrossReferences` iterated
+the registered list (`config.actions`) and — since #6889 — inline page-element actions.
+Neither walk visited actions authored directly on an object
+(`config.objects[].actions[]`), even though that position carries the **full
+`ActionSchema`**: the identical symbol the registered collection uses, not a narrower
+embedded shape. So a `type: 'modal'` or `type: 'flow'` target written there was never
+resolved. The card's ten-row probe, measured on `main` before this change — every stack
+declares both a page and a flow, so the plugin size-gate cannot explain the acceptances,
+and each embedded row's registered twin is built from the same helper with the same
+arguments:
+
+```
+a embedded   modal -> page    :  ACCEPTED   (h registered: ACCEPTED)
+b embedded   modal -> nothing :  ACCEPTED   (f registered: REJECTED)  <- split
+c embedded   flow  -> nothing :  ACCEPTED   (g registered: REJECTED)  <- split
+d embedded   modal -> object  :  ACCEPTED   (i registered: REJECTED)  <- split
+e embedded   flow  -> flow    :  ACCEPTED   (j registered: ACCEPTED)
+```
+
+Rows b/f, c/g and d/i are the **same action object in two authoring positions with
+opposite verdicts**. Row b is the defect on its own terms — a target naming nothing at all
+built clean, shipped, and failed only when a user clicked it.
+
+Why the registered walk could not already cover it: `validateCrossReferences` runs
+**before** `mergeActionsIntoObjects`, and that merge only ever copies top-level → object
+(by `objectName`), never the reverse. An action authored only on the object therefore
+never appeared in the validated `config.actions` at all.
+
+**Now**: `config.objects[].actions[]` is walked and every action found is subjected to the
+**same** two target checks as a registered one — same rule, same message tail, same size
+gates. Messages keep the registered wording from `references` onward and change only the
+subject, because an embedded action is located by its owning object (`name` is required at
+this position, so it is always available):
+
+```
+Action 'new_task' on object 'task' references page 'nowhere' (via modal target) which is
+not defined in pages.
+```
+
+Scope of the modal arm is the maintainer's ruling on #6739 (2026-08-09): **a
+`type: 'modal'` target names a PAGE, only** — so this arm mirrors the registered one
+rather than also accepting an object name, closing the d/i split exactly as #6889 closed
+the inline one. `objectName` is deliberately left unchecked at this position: the key does
+exist on this shape, but what it should mean on an action already embedded on an object —
+a mere existence check, or a consistency check against the owning object's name — is an
+open contract question filed separately rather than settled as a side effect of this walk.
+
+**Acceptance-face narrowing.** A stack carrying a dangling embedded `modal`/`flow` target
+now fails to build where it previously built clean. Census of the shipped corpus found
+**zero** stacks affected: no object in the reference corpus hand-authors a `modal`- or
+`flow`-typed action at this position, and the ordinary way `objects[].actions[]` gets
+populated — the top-level → object merge — runs after validation and is unaffected. A
+vacuity guard pins that merged shape so the census cannot go stale silently.
diff --git a/packages/spec/src/stack-inline-action-crossref.test.ts b/packages/spec/src/stack-inline-action-crossref.test.ts
index f5d86a021e..1f386c26e3 100644
--- a/packages/spec/src/stack-inline-action-crossref.test.ts
+++ b/packages/spec/src/stack-inline-action-crossref.test.ts
@@ -1,6 +1,7 @@
 /**
- * `defineStack` cross-reference validation reaches INLINE (page-element)
- * actions — #6889.
+ * `defineStack` cross-reference validation reaches every authoring position an
+ * action's modal/flow `target` can be written in — INLINE page-element actions
+ * (#6889) and OBJECT-EMBEDDED actions (#7397).
  *
  * An action authored inline on a page element (`element:button` →
  * `properties.action`, an `InlineActionSchema`) never enters `config.actions`,
@@ -22,6 +23,28 @@
  * mirrors registered exactly — same rule, same message tail, one more
  * traversal.
  *
+ * The SECOND half of this file is the same defect one authoring position over
+ * (#7397). `config.objects[].actions[]` carries the FULL `ActionSchema` — the
+ * identical symbol the registered collection uses — yet it too was never
+ * target-validated, because `validateCrossReferences` runs BEFORE
+ * `mergeActionsIntoObjects` and that merge only ever copies top-level →
+ * object. An action authored only on the object therefore never appeared in
+ * the validated `config.actions`. Measured on `main` @ `d13ce33`, with the
+ * registered twin of each row built from the same helper and the same
+ * arguments as the control:
+ *
+ * ```
+ * a embedded   modal -> page    :  ACCEPTED   (h registered: ACCEPTED)
+ * b embedded   modal -> nothing :  ACCEPTED   (f registered: REJECTED) ← split
+ * c embedded   flow  -> nothing :  ACCEPTED   (g registered: REJECTED) ← split
+ * d embedded   modal -> object  :  ACCEPTED   (i registered: REJECTED) ← split
+ * e embedded   flow  -> flow    :  ACCEPTED   (j registered: ACCEPTED)
+ * ```
+ *
+ * Rows b/f, c/g and d/i are the same action object in two authoring positions
+ * with opposite verdicts; a/h and e/j confirm the legitimate shapes survive in
+ * both. Row d's verdict is fixed by the same #6739 ruling, not re-decided here.
+ *
  * Message shape is contract here (one condition ⇒ one wording), so these pin
  * full message text rather than `toThrow()` alone: a bare throw assertion
  * cannot tell "refused for the right reason" from "refused because the fixture
@@ -252,3 +275,204 @@ describe('defineStack — inline action cross-references: what the walk must NOT
     }))).toEqual([]);
   });
 });
+
+// ─── #7397 — the OBJECT-EMBEDDED position ────────────────────────────
+
+const pages = [pageWith([])];
+
+/**
+ * A stack whose ONLY action is embedded on the object — no `config.actions` at
+ * all, which is exactly the shape the top-level → object merge can never
+ * reach.
+ */
+const embeddedStack = (action: unknown, extra: Record<string, unknown> = {}) => ({
+  manifest: baseManifest,
+  objects: [{ ...objects[0], actions: [action] }],
+  pages,
+  ...extra,
+});
+
+/** The same action in the REGISTERED position — the control for each row. */
+const registeredStack = (action: unknown, extra: Record<string, unknown> = {}) => ({
+  manifest: baseManifest,
+  objects,
+  pages,
+  actions: [action],
+  ...extra,
+});
+
+const modalAction = (target: string) => ({ name: 'probe_new_task', label: 'New', type: 'modal' as const, target });
+const flowAction = (target: string) => ({ name: 'probe_run', label: 'Run', type: 'flow' as const, target });
+
+describe('defineStack — object-embedded action cross-references: modal targets (#7397)', () => {
+  it('rejects a dangling embedded modal target (probe row b) with the registered rule\'s wording', () => {
+    expect(refusals(embeddedStack(modalAction('probe_nowhere')))).toEqual([
+      "Action 'probe_new_task' on object 'probe_task' "
+      + "references page 'probe_nowhere' (via modal target) which is not defined in pages.",
+    ]);
+  });
+
+  it('rejects an embedded modal target naming an OBJECT — #6739 ruling A, a modal target names a page (probe row d)', () => {
+    expect(refusals(embeddedStack(modalAction('probe_task')))).toEqual([
+      "Action 'probe_new_task' on object 'probe_task' "
+      + "references page 'probe_task' (via modal target) which is not defined in pages.",
+    ]);
+  });
+
+  it('accepts an embedded modal target naming a declared page — the legitimate shape survives (probe row a)', () => {
+    expect(refusals(embeddedStack(modalAction('probe_home')))).toEqual([]);
+  });
+
+  it('skips embedded modal targets when the stack declares NO pages — same size gate as the registered rule', () => {
+    // The referenced page may be provided by a plugin; embedded must not be
+    // stricter than registered.
+    expect(refusals({
+      manifest: baseManifest,
+      objects: [{ ...objects[0], actions: [modalAction('probe_nowhere')] }],
+    })).toEqual([]);
+  });
+});
+
+describe('defineStack — object-embedded action cross-references: flow targets (#7397)', () => {
+  it('rejects an embedded flow target that names no declared flow (probe row c)', () => {
+    expect(refusals(embeddedStack(flowAction('probe_nowhere'), { flows }))).toEqual([
+      "Action 'probe_run' on object 'probe_task' "
+      + "references flow 'probe_nowhere' which is not defined in flows.",
+    ]);
+  });
+
+  it('accepts an embedded flow target that names a declared flow (probe row e)', () => {
+    expect(refusals(embeddedStack(flowAction('probe_flow'), { flows }))).toEqual([]);
+  });
+
+  it('skips embedded flow targets when the stack declares NO flows — same size gate as the registered rule', () => {
+    expect(refusals(embeddedStack(flowAction('probe_nowhere')))).toEqual([]);
+  });
+});
+
+describe('defineStack — object-embedded action cross-references: the b/f, c/g, d/i splits (#7397)', () => {
+  it.each([
+    ['modal → nothing (rows b/f)', modalAction('probe_nowhere')],
+    ['modal → object  (rows d/i)', modalAction('probe_task')],
+    ['flow  → nothing (rows c/g)', flowAction('probe_nowhere')],
+  ])('gives the same verdict embedded or registered: %s', (_label, action) => {
+    expect(refusals(embeddedStack(action, { flows })).length).toBe(1);
+    expect(refusals(registeredStack(action, { flows })).length).toBe(1);
+  });
+
+  it.each([
+    ['modal → declared page (rows a/h)', modalAction('probe_home')],
+    ['flow  → declared flow (rows e/j)', flowAction('probe_flow')],
+  ])('accepts in BOTH positions: %s', (_label, action) => {
+    expect(refusals(embeddedStack(action, { flows }))).toEqual([]);
+    expect(refusals(registeredStack(action, { flows }))).toEqual([]);
+  });
+});
+
+describe('defineStack — object-embedded action cross-references: the traversal itself (#7397)', () => {
+  it('labels each offender with ITS OWN object, not a fixed subject', () => {
+    const config = {
+      manifest: baseManifest,
+      objects: [
+        { ...objects[0], actions: [modalAction('probe_nowhere')] },
+        {
+          name: 'probe_note',
+          label: 'Probe Note',
+          fields: { body: { type: 'text' as const } },
+          actions: [flowAction('probe_elsewhere')],
+        },
+      ],
+      pages,
+      flows,
+    };
+
+    expect(refusals(config)).toEqual([
+      "Action 'probe_new_task' on object 'probe_task' "
+      + "references page 'probe_nowhere' (via modal target) which is not defined in pages.",
+      "Action 'probe_run' on object 'probe_note' "
+      + "references flow 'probe_elsewhere' which is not defined in flows.",
+    ]);
+  });
+
+  it('reports every offending action on one object, not just the first', () => {
+    const config = {
+      manifest: baseManifest,
+      objects: [{
+        ...objects[0],
+        actions: [
+          { name: 'probe_one', label: 'One', type: 'modal' as const, target: 'probe_nowhere' },
+          { name: 'probe_two', label: 'Two', type: 'flow' as const, target: 'probe_elsewhere' },
+        ],
+      }],
+      pages,
+      flows,
+    };
+
+    expect(refusals(config)).toEqual([
+      "Action 'probe_one' on object 'probe_task' "
+      + "references page 'probe_nowhere' (via modal target) which is not defined in pages.",
+      "Action 'probe_two' on object 'probe_task' "
+      + "references flow 'probe_elsewhere' which is not defined in flows.",
+    ]);
+  });
+
+  it('reports a registered action ONCE, not twice — the merge runs AFTER validation', () => {
+    // `mergeActionsIntoObjects` copies a top-level action carrying `objectName`
+    // into that object's `actions`. It runs at the END of `defineStack`, so the
+    // embedded walk must not see the copy. If validation is ever reordered
+    // ahead of the merge, this case starts reporting the same action twice —
+    // once as registered, once as embedded — and goes red.
+    const config = {
+      manifest: baseManifest,
+      objects,
+      pages,
+      actions: [{ ...modalAction('probe_nowhere'), objectName: 'probe_task' }],
+    };
+
+    expect(refusals(config)).toEqual([
+      "Action 'probe_new_task' references page 'probe_nowhere' (via modal target) which is not defined in pages.",
+    ]);
+  });
+
+  it('still checks the target of an embedded action that also names its object', () => {
+    expect(refusals(embeddedStack({ ...modalAction('probe_nowhere'), objectName: 'probe_task' }))).toEqual([
+      "Action 'probe_new_task' on object 'probe_task' "
+      + "references page 'probe_nowhere' (via modal target) which is not defined in pages.",
+    ]);
+  });
+
+  it('leaves an object with no actions array alone', () => {
+    expect(refusals({ manifest: baseManifest, objects, pages, flows })).toEqual([]);
+  });
+});
+
+describe('defineStack — object-embedded action cross-references: what the walk must NOT refuse (#7397)', () => {
+  it.each([
+    ['form', { name: 'probe_form', label: 'Form', type: 'form', target: 'probe_task.edit' }],
+    ['url', { name: 'probe_url', label: 'Url', type: 'url', target: '/environments' }],
+    ['api', { name: 'probe_api', label: 'Api', type: 'api', target: '/api/v1/x', method: 'POST' }],
+    ['script', { name: 'probe_script', label: 'Script', type: 'script', target: 'doThing' }],
+  ])('leaves an embedded `%s` action alone — only modal and flow targets are cross-referenced', (_type, action) => {
+    expect(refusals(embeddedStack(action, { flows }))).toEqual([]);
+  });
+
+  it('is vacuity-guarded: the ordinary merged shape a shipped stack produces still builds', () => {
+    // `objects[].actions[]` is overwhelmingly WRITTEN by the merge rather than
+    // by hand — a top-level action with `objectName` lands there on the way
+    // out of `defineStack`. Feeding that output back in must stay clean, or the
+    // corpus census in PR #7397 has gone stale.
+    const built = build({
+      manifest: baseManifest,
+      objects,
+      pages,
+      flows,
+      actions: [
+        { ...modalAction('probe_home'), objectName: 'probe_task' },
+        { ...flowAction('probe_flow'), objectName: 'probe_task' },
+      ],
+    });
+
+    expect(built.objects?.[0]?.actions?.map((a) => a.name)).toEqual(['probe_new_task', 'probe_run']);
+    expect(refusals(built)).toEqual([]);
+  });
+});
diff --git a/packages/spec/src/stack.zod.ts b/packages/spec/src/stack.zod.ts
index 8c5ef29816..ae8ee8761b 100644
--- a/packages/spec/src/stack.zod.ts
+++ b/packages/spec/src/stack.zod.ts
@@ -1153,6 +1153,51 @@ function validateCrossReferences(config: ObjectStackDefinition): string[] {
     }
   }
 
+  // The SAME two target checks, one more traversal: actions authored directly
+  // on an object (`config.objects[].actions[]`) — #7397, the #6889 defect one
+  // authoring position over.
+  //
+  // Why the registered walk above cannot cover it: `validateCrossReferences`
+  // runs BEFORE `mergeActionsIntoObjects`, and that merge only ever copies
+  // top-level → object (by `objectName`), never the reverse. An action authored
+  // ONLY on the object therefore never appears in `config.actions` and reached
+  // no cross-reference check at all — measured on #7397, where an embedded
+  // `type: 'modal', target: 'probe_nowhere'` built clean while the identical
+  // action in the registered position was refused.
+  //
+  // This position carries the FULL `ActionSchema` (`object.zod.ts`'s
+  // `actions: z.array(ActionSchema)`) — the identical symbol the registered
+  // collection uses at `:256`, not a narrower embedded shape — so `name` is
+  // required here and `target` has already been canonicalized by the parse
+  // this function runs after. Only the SUBJECT of the message differs from the
+  // registered rule: an embedded action is located by its owning object.
+  //
+  // Scope of the modal branch is the same #6739 ruling the other two arms
+  // read: a `type: 'modal'` target names a PAGE, only.
+  //
+  // `objectName` is deliberately NOT checked here. The key exists on this
+  // shape (unlike the inline one), but what it should MEAN on an action
+  // already embedded on an object — a mere existence check, or a consistency
+  // check against the owning object's name — is an open contract question,
+  // filed separately rather than settled as a side effect of this walk.
+  if (config.objects) {
+    for (const obj of config.objects) {
+      for (const action of obj.actions ?? []) {
+        if (action.type === 'flow' && action.target && flowNames.size > 0 && !flowNames.has(action.target)) {
+          errors.push(
+            `Action '${action.name}' on object '${obj.name}' references flow '${action.target}' which is not defined in flows.`,
+          );
+        }
+
+        if (action.type === 'modal' && action.target && pageNames.size > 0 && !pageNames.has(action.target)) {
+          errors.push(
+            `Action '${action.name}' on object '${obj.name}' references page '${action.target}' (via modal target) which is not defined in pages.`,
+          );
+        }
+      }
+    }
+  }
+
   // The SAME two target checks, one more traversal: inline (page-element)
   // actions (#6889). Same rule, same message tail — only the subject differs,
   // because an inline action is located by page + path rather than by a