diff --git a/dsh/bundle/index.js b/dsh/bundle/index.js
index a0bb9a3..eefaa10 100644
--- a/dsh/bundle/index.js
+++ b/dsh/bundle/index.js
@@ -73,10 +73,11 @@ export function resolveRolesDir(bundleDir, configured, home = homedir()) {
 
 
 function isSubagent(agent) {
-  if (!agent) return false
-  if (agent.parent || agent.parentAgent || agent.parentSessionId) return true
-  if (typeof agent.depth === 'number' && agent.depth > 0) return true
-  return false
+  return Boolean(
+    agent?.session?.header?.delegationDepth > 0 ||
+    agent?.session?.header?.parentSession != null ||
+    agent?.options?.subagentDepth > 0,
+  )
 }
 
 function sessionCwd(workingDirectory, agent) {
diff --git a/dsh/tests/prestep.test.mjs b/dsh/tests/prestep.test.mjs
index 972275c..0ddff3f 100644
--- a/dsh/tests/prestep.test.mjs
+++ b/dsh/tests/prestep.test.mjs
@@ -377,3 +377,56 @@ test('apply: bootstrap:false leaves harness-check wired (the gate is ctx.on, not
     cleanup(repo)
   }
 })
+
+// ---------------------------------------------------------------------------
+// Subagent skip (T2.1): real runtime delegation signals
+// ---------------------------------------------------------------------------
+
+/**
+ * Agent shapes that the runtime uses for a delegated step. The old
+ * parent/parentAgent/parentSessionId/depth checks were dead; these three are
+ * the live ones.
+ */
+const SUBAGENT_AGENTS = [
+  { session: { header: { delegationDepth: 1 } } },
+  { session: { header: { parentSession: 's0' } } },
+  { options: { subagentDepth: 1 } },
+]
+
+test('apply: a delegated pre-step injects nothing (bootstrap, harness-check, role-hint)', async () => {
+  const repo = nonAdoptedRepo()
+  const skill = tempDir('dsh-harness-skill-')
+  try {
+    write(join(skill, 'SKILL.md'), '---\nname: using-superpowers\n---\nbody\n')
+    const harness = prestepHarness({ bootstrapSkillPath: join(skill, 'SKILL.md') }, repo)
+
+    for (const agent of SUBAGENT_AGENTS) {
+      const decision = await harness.run({ agent, messages: [userMessage('Напиши тест')] })
+      assert.equal(decision.messages.length, 1, `no injection for ${JSON.stringify(agent)}`)
+      assert.equal(messageText(decision.messages[0]), 'Напиши тест')
+    }
+  } finally {
+    cleanup(repo)
+    cleanup(skill)
+  }
+})
+
+test('apply: a plain pre-step still injects bootstrap, harness-check, and role-hint', async () => {
+  const repo = nonAdoptedRepo()
+  const skill = tempDir('dsh-harness-skill-')
+  try {
+    write(join(skill, 'SKILL.md'), '---\nname: using-superpowers\n---\nbody\n')
+    const harness = prestepHarness({ bootstrapSkillPath: join(skill, 'SKILL.md') }, repo)
+    const decision = await harness.run({ agent: { session: 's1' }, messages: [userMessage('Напиши тест')] })
+
+    assert.equal(decision.messages.length, 4)
+    assert.equal(messageText(decision.messages[0]), 'Напиши тест')
+    const texts = decision.messages.map(messageText)
+    assert.ok(texts.some((text) => text.includes('DSH-HARNESS-BOOTSTRAP')), 'bootstrap injected')
+    assert.ok(texts.some((text) => text.includes('не подключён к обвязке')), 'harness-check injected')
+    assert.ok(texts.some((text) => text.includes('Роль сессии: dev')), 'role-hint injected')
+  } finally {
+    cleanup(repo)
+    cleanup(skill)
+  }
+})