diff --git a/src/core/environment/__tests__/getEnvironmentDetails.spec.ts b/src/core/environment/__tests__/getEnvironmentDetails.spec.ts
index df47e83c21..bede9c912b 100644
--- a/src/core/environment/__tests__/getEnvironmentDetails.spec.ts
+++ b/src/core/environment/__tests__/getEnvironmentDetails.spec.ts
@@ -464,4 +464,31 @@ describe("getEnvironmentDetails", () => {
 		const result = await getEnvironmentDetails(mockCline as Task, true)
 		expect(result).toContain("File listing unavailable: unexpected string rejection")
 	})
+
+	it("should surface task nesting depth for a root task", async () => {
+		mockCline = { ...mockCline, depth: 0 }
+
+		const result = await getEnvironmentDetails(mockCline as Task)
+
+		expect(result).toContain("# Task Context")
+		expect(result).toContain("Nesting depth: 0 (root = 0)")
+		expect(result).not.toContain("Parent task:")
+	})
+
+	it("should surface nesting depth and parent id for a child task", async () => {
+		mockCline = { ...mockCline, depth: 2, parentTaskId: "parent-task-id" }
+
+		const result = await getEnvironmentDetails(mockCline as Task)
+
+		expect(result).toContain("# Task Context")
+		expect(result).toContain("Nesting depth: 2 (root = 0)")
+		expect(result).toContain("Parent task: parent-task-id")
+	})
+
+	it("should omit the task context section when depth is unknown", async () => {
+		const result = await getEnvironmentDetails(mockCline as Task)
+
+		expect(result).not.toContain("# Task Context")
+		expect(result).not.toContain("Nesting depth:")
+	})
 })
diff --git a/src/core/environment/getEnvironmentDetails.ts b/src/core/environment/getEnvironmentDetails.ts
index 0e7d18a57a..7d5ee59379 100644
--- a/src/core/environment/getEnvironmentDetails.ts
+++ b/src/core/environment/getEnvironmentDetails.ts
@@ -226,6 +226,18 @@ export async function getEnvironmentDetails(cline: Task, includeFileDetails: boo
 	details += `<name>${modeDetails.name}</name>\n`
 	details += `<model>${modelId}</model>\n`
 
+	// Surface this task's position in the delegation tree so a subtask can report
+	// its own nesting level — depth is never visible to the model anywhere else.
+	// The parent id is included only for children; resolving the parent's title
+	// would need a history-store lookup on every environment refresh, which we avoid.
+	if (typeof cline.depth === "number") {
+		details += `\n\n# Task Context`
+		details += `Nesting depth: ${cline.depth} (root = 0)`
+		if (cline.parentTaskId) {
+			details += `\nParent task: ${cline.parentTaskId}`
+		}
+	}
+
 	if (includeFileDetails) {
 		details += `\n\n# Current Workspace Directory (${cline.cwd.toPosix()}) Files\n`
 		const isDesktop = arePathsEqual(cline.cwd, path.join(os.homedir(), "Desktop"))