diff --git a/docs/reference/required-work-context.md b/docs/reference/required-work-context.md
index 5759fb9b84..d2791c1347 100644
--- a/docs/reference/required-work-context.md
+++ b/docs/reference/required-work-context.md
@@ -862,6 +862,16 @@ not renumber arguments. Inspect the resolved prefix before that token in the
 same capture; malformed pointers need syntax repair first. Diagnostics never
 echo the pointer or task values, and no part of a rejected batch is delivered.
 
+Reader failures preserve the runtime's `error_kind` and `diagnostic_code` so
+programs need not parse `reason`. Selector rejections use `request_rejected`
+with `context_selection_invalid_pointer`, `context_selection_invalid_index`
+or `context_selection_missing_pointer`. Repair the pointer syntax or inspect
+the known parent in the same capture, then retry the corrected batch. Other
+runtime failures retain their own classification; startup failures retain
+their diagnostic code. These failures do not require restoring a healthy
+capture. Missing or damaged capture files still fail closed through the
+original file/digest checks. Reading again never reruns admission.
+
 The `context_capture_index_v1` view shares the digest-bound pagination contract.
 An expanded index includes its `list_depth`; `next_command` preserves the depth,
 selectors and both hashes. Changing depth rejects the prior view's continuation.
@@ -905,6 +915,13 @@ pointer 从原始摘要绑定的 capture 批量读取详情。提供已有 `--ca
 路径前缀；语法错误需先修正 pointer。错误信息不回显路径或任务正文，被拒绝的
 批次不会返回部分内容。
 
+读取失败保留 runtime 的 `error_kind` 与 `diagnostic_code`，程序无需解析 `reason`。
+选择错误使用 `request_rejected`，原因码分别为 `context_selection_invalid_pointer`、
+`context_selection_invalid_index` 或 `context_selection_missing_pointer`。
+修正路径语法或在同一 capture 中检查已知父节点，再重试修正后的批次。其他 runtime
+故障保留自身分类；启动故障保留原诊断码。这些故障不要求恢复健康的 capture。
+文件缺失或损坏仍由原文件/摘要检查拒绝，重新读取不会重新准入。
+
 `context_capture_index_v1` 沿用双摘要分页；展开的目录包含 `list_depth`，
 `next_command` 保留深度、路径和两个摘要。更改深度会拒绝旧视图的续读，目录 cursor
 也不能用作正文 cursor。遇到输出截断或缺页，用足够的输出预算恢复同一 capture
diff --git a/loopx/cli_commands/quota_capture.py b/loopx/cli_commands/quota_capture.py
index 09261c0f4e..e933c67783 100644
--- a/loopx/cli_commands/quota_capture.py
+++ b/loopx/cli_commands/quota_capture.py
@@ -197,10 +197,20 @@ def read_context_capture(args: argparse.Namespace, *, presentation: dict[str, An
     except (OSError, ValueError, RecursionError, EffectRuntimeRemoteError, EffectRuntimeStartupError) as exc:
         # Recovery is presentation-only: keep failures separate from quota's
         # collection error path and retain the existing receipt/capture.
-        return {"ok": False, "schema_version": "context_capture_page_v1",
+        result = {"ok": False, "schema_version": "context_capture_page_v1",
             "reason": str(exc) if isinstance(exc, (ValueError, EffectRuntimeRemoteError, EffectRuntimeStartupError))
                 else "original capture could not be read",
             "recovery": "Restore the original digest-bound capture; no guard, admission or spend was performed."}
+        if isinstance(exc, (EffectRuntimeRemoteError, EffectRuntimeStartupError)):
+            result["diagnostic_code"] = exc.diagnostic_code
+            result["recovery"] = ("Resolve the reported runtime failure, then retry reading the same digest-bound capture; "
+                "no guard, admission or spend was performed.")
+        if isinstance(exc, EffectRuntimeRemoteError):
+            result["error_kind"] = exc.error_kind
+            if exc.error_kind == "request_rejected":
+                result["recovery"] = ("Correct the rejected read request; for unknown fields use --list on a known parent. "
+                    "Keep the original capture and digest; no guard, admission or spend was performed.")
+        return result
 
 
 def native_context_capture_view(projected: dict[str, Any], directory: Path, *,
diff --git a/loopx/control_plane/quota/context_selection.ts b/loopx/control_plane/quota/context_selection.ts
index 379bb01670..69e4d07b46 100644
--- a/loopx/control_plane/quota/context_selection.ts
+++ b/loopx/control_plane/quota/context_selection.ts
@@ -22,20 +22,23 @@ export function capturedContextSelection(request: JsonObject): JsonObject {
   const selections = pointers.map(pointer => {
     const argument = `--select argument ${argumentsByPointer.get(pointer)}`;
     if (pointer !== "" && !pointer.startsWith("/") || /~(?:[^01]|$)/.test(pointer))
-      throw new EffectRuntimeRequestError(`context selection requires RFC 6901 pointers (${argument}; positions are 1-based)`);
+      throw new EffectRuntimeRequestError(`context selection requires RFC 6901 pointers (${argument}; positions are 1-based)`,
+        "context_selection_invalid_pointer");
     const tokens = pointer === "" ? [] : pointer.slice(1).split("/").map(token => token.replace(/~1/g, "/").replace(/~0/g, "~"));
     const path: (string | number)[] = [];
     let value: unknown = context;
     for (const token of tokens) {
       if (Array.isArray(value)) {
         if (!/^(0|[1-9][0-9]*)$/.test(token) || !Number.isSafeInteger(Number(token)) || Number(token) >= value.length)
-          throw new EffectRuntimeRequestError(`context selection array index is missing or invalid (${argument}, token ${path.length + 1}; positions are 1-based)`);
+          throw new EffectRuntimeRequestError(`context selection array index is missing or invalid (${argument}, token ${path.length + 1}; positions are 1-based)`,
+            "context_selection_invalid_index");
         path.push(Number(token));
         value = value[Number(token)];
       } else if (value !== null && typeof value === "object" && Object.hasOwn(value, token)) {
         path.push(token);
         value = (value as JsonObject)[token];
-      } else throw new EffectRuntimeRequestError(`context selection pointer does not exist (${argument}, token ${path.length + 1}; positions are 1-based)`);
+      } else throw new EffectRuntimeRequestError(`context selection pointer does not exist (${argument}, token ${path.length + 1}; positions are 1-based)`,
+        "context_selection_missing_pointer");
     }
     // Return the verified address, not a JS-number-coerced copy of the value.
     // The file adapter retains original JSON values and owns byte serialization.
diff --git a/tests/control_plane/test_context_capture_selection.py b/tests/control_plane/test_context_capture_selection.py
index 1e17306737..3af19b2968 100644
--- a/tests/control_plane/test_context_capture_selection.py
+++ b/tests/control_plane/test_context_capture_selection.py
@@ -8,6 +8,7 @@
 
 from tests.control_plane.codex_checkpoint_fixture import NativeContextReader, last_context_page
 from loopx.cli_commands.quota_capture import read_context_capture
+from loopx.control_plane.effect_runtime import EffectRuntimeRemoteError, EffectRuntimeStartupError
 from loopx.control_plane.turn_driver.decision_capture import capture_page_range
 from test_quota_settlement_cli import _run_cli
 
@@ -276,3 +277,92 @@ def test_cli_missing_batch_pointer_identifies_original_argument_without_source_l
     assert f"--select argument 3, token {token}" in result["reason"]
     assert pointer not in result["reason"] and "stop if unavailable" not in json.dumps(result)
     assert path.read_bytes() == raw and not registry.exists() and not runtime.exists()
+
+
+def test_cli_repairs_missing_selection_using_typed_error_and_same_capture(tmp_path):
+    path, raw, original = fixture_capture(tmp_path)
+    registry, runtime = tmp_path / "absent.json", tmp_path / "absent-runtime"
+    command = ["quota", "context-read", "--capture-file", str(path),
+        "--capture-sha256", hashlib.sha256(raw).hexdigest()]
+    code, failure = _run_cli(registry, runtime, *command,
+        "--select", "/large", "--select", "/rows/0/missing", cwd=tmp_path)
+    assert code != 0 and failure["ok"] is False and "content" not in failure
+    assert failure["error_kind"] == "request_rejected"
+    assert failure["diagnostic_code"] == "context_selection_missing_pointer"
+    assert "--list" in failure["recovery"] and "Restore" not in failure["recovery"]
+    # Branch on the typed cause, not wording in reason; discover and retry
+    # against the original capture without another guard or admission.
+    code, index = _run_cli(registry, runtime, *command, "--select", "/rows/0", "--list", cwd=tmp_path)
+    assert code == 0 and index["ok"] and index["eof"], index
+    fields = json.loads(index["content"])["selections"][0]["fields"]
+    pointer = next(field["pointer"] for field in fields if field["pointer"] == "/rows/0/tail")
+    code, selected = _run_cli(registry, runtime, *command, "--select", pointer, cwd=tmp_path)
+    assert code == 0 and selected["ok"] and selected["eof"], selected
+    assert json.loads(selected["content"])["selections"] == [
+        {"pointer": pointer, "value": original["rows"][0]["tail"]}]
+    assert capture_page_range(selected, raw=raw, digest=selected["sha256"]) is None
+    assert path.read_bytes() == raw and not registry.exists() and not runtime.exists()
+
+
+@pytest.mark.parametrize("kind,code", [
+    ("request_rejected", "request_too_large"),
+    ("io_transient", "io_busy"),
+    ("io_permanent", "io_permission_denied"),
+    ("internal_failure", "unexpected_handler_error"),
+])
+def test_reader_preserves_runtime_diagnostics_without_parsing_reason(tmp_path, monkeypatch, kind, code):
+    from loopx.control_plane.quota import turn_envelope
+
+    path, raw, _ = fixture_capture(tmp_path)
+
+    def fail(*_args, **_kwargs):
+        raise EffectRuntimeRemoteError("same opaque reason", error_kind=kind, diagnostic_code=code)
+
+    monkeypatch.setattr(turn_envelope, "_turn_envelope_result", fail)
+    result = read_context_capture(args(path, raw))
+    assert result["ok"] is False and "content" not in result and "next_command" not in result
+    assert result["error_kind"] == kind and result["diagnostic_code"] == code
+    assert result["reason"] == "same opaque reason"
+    assert "Restore" not in result["recovery"]
+    assert ("--list" in result["recovery"]) is (kind == "request_rejected")
+    assert path.read_bytes() == raw
+
+
+def test_runtime_startup_failure_does_not_request_capture_restoration(tmp_path, monkeypatch):
+    from loopx.control_plane.quota import turn_envelope
+
+    path, raw, _ = fixture_capture(tmp_path)
+
+    def fail(*_args, **_kwargs):
+        raise EffectRuntimeStartupError("runtime unavailable", diagnostic_code="runtime_startup_timeout")
+
+    monkeypatch.setattr(turn_envelope, "_turn_envelope_result", fail)
+    result = read_context_capture(args(path, raw))
+    assert result["ok"] is False and "content" not in result
+    assert result["diagnostic_code"] == "runtime_startup_timeout"
+    assert "runtime" in result["recovery"] and "Restore" not in result["recovery"]
+    assert path.read_bytes() == raw
+
+
+@pytest.mark.parametrize("damage", ["missing", "digest", "json"])
+def test_capture_failure_cannot_be_repaired_as_a_selector_error(tmp_path, monkeypatch, damage):
+    from loopx.control_plane.quota import turn_envelope
+
+    path, raw, _ = fixture_capture(tmp_path)
+    request = args(path, raw)
+    if damage == "missing":
+        path.unlink()
+    elif damage == "digest":
+        path.write_bytes(b"{}")
+    else:
+        path.write_bytes(b"{broken")
+        request.capture_sha256 = hashlib.sha256(path.read_bytes()).hexdigest()
+
+    def unexpected(*_args, **_kwargs):
+        pytest.fail("invalid captures must not reach selection")
+
+    monkeypatch.setattr(turn_envelope, "_turn_envelope_result", unexpected)
+    result = read_context_capture(request)
+    assert result["ok"] is False and "content" not in result and "next_command" not in result
+    assert "diagnostic_code" not in result and "error_kind" not in result
+    assert "Restore the original digest-bound capture" in result["recovery"]
diff --git a/tests/control_plane_ts/context_selection.test.ts b/tests/control_plane_ts/context_selection.test.ts
index c8a82133f2..d0ad4f6a58 100644
--- a/tests/control_plane_ts/context_selection.test.ts
+++ b/tests/control_plane_ts/context_selection.test.ts
@@ -1,6 +1,7 @@
 import assert from "node:assert/strict";
 import {test} from "node:test";
 import {evaluateTurnEnvelope} from "../../loopx/control_plane/quota/turn_envelope.ts";
+import {effectRuntimeErrorPayload} from "../../loopx/control_plane/effect_runtime_errors.ts";
 
 const select = (context: object, pointers: unknown) => evaluateTurnEnvelope({operation: "context_select", context, select: pointers});
 
@@ -70,3 +71,23 @@ test("selection failures identify original argument and token without echoing co
   }
   assert.throws(() => select(context, ["/z", "secret-".repeat(1000)]), /--select argument 2/);
 });
+
+test("selection failures retain machine-readable causes at the runtime boundary", () => {
+  const context = {rows: [{stop: "private-value"}]};
+  for (const [pointer, code] of [
+    ["rows", "context_selection_invalid_pointer"],
+    ["/~2", "context_selection_invalid_pointer"],
+    ["/rows/01", "context_selection_invalid_index"],
+    ["/rows/9", "context_selection_invalid_index"],
+    ["/rows/0/missing", "context_selection_missing_pointer"],
+    ["/toString", "context_selection_missing_pointer"],
+  ]) {
+    assert.throws(() => select(context, ["/rows", pointer]), (error: unknown) => {
+      const failure = effectRuntimeErrorPayload(error);
+      assert.equal(failure.kind, "request_rejected");
+      assert.equal(failure.code, code);
+      assert.ok(!failure.message.includes(pointer) && !failure.message.includes("private-value"));
+      return true;
+    });
+  }
+});