chore(ui,agent): harden collector parsing, drop dead CSS, resilver label

Addresses final code review:
- to_int/1 now returns 0 on nil or unparseable strings instead of crashing
- remove unused .pool-row CSS (superseded by .pool-block)
- clamp capacity bar width to [0, 100] to prevent visual overflow
- pool_scrub_line/1 uses scan_function so resilver shows as "resilver..."

agent/lib/proxmox_agent/collectors/zfs.ex

@@ -4,6 +4,15 @@ defmodule ProxmoxAgent.Collectors.Zfs do
   Delegates shelling out to an injectable runner so tests can supply fixtures.
   """
 
+  @type vdev_summary :: %{
+          name: String.t(),
+          type: String.t(),
+          state: String.t(),
+          read_errors: non_neg_integer(),
+          write_errors: non_neg_integer(),
+          checksum_errors: non_neg_integer()
+        }
+
   @type pool_summary :: %{
           name: String.t(),
           health: String.t(),
@@ -15,7 +24,11 @@ defmodule ProxmoxAgent.Collectors.Zfs do
           error_count: non_neg_integer(),
           vdev_count: non_neg_integer(),
           degraded_vdev_count: non_neg_integer(),
-          last_scrub_end: String.t() | nil
+          pool_type: String.t(),
+          scan_function: String.t() | nil,
+          scan_state: String.t() | nil,
+          last_scrub_end: String.t() | nil,
+          vdevs: [vdev_summary()]
         }
 
   @spec collect_pools(keyword()) :: %{pools: [pool_summary()], errors: [map()]}
@@ -71,7 +84,8 @@ defmodule ProxmoxAgent.Collectors.Zfs do
   defp merge_pools(%{"pools" => list_pools}, %{"pools" => status_pools}) do
     Enum.map(list_pools, fn {name, list_info} ->
       status_info = Map.get(status_pools, name, %{})
-      vdevs = Map.get(status_info, "vdevs", %{}) |> Map.values()
+      raw_vdevs = Map.get(status_info, "vdevs", %{}) |> Map.values()
+      vdevs = Enum.map(raw_vdevs, &vdev_summary/1)
 
       %{
         name: name,
@@ -83,12 +97,45 @@ defmodule ProxmoxAgent.Collectors.Zfs do
         capacity_percent: Map.get(list_info, "cap", 0),
         error_count: to_int(Map.get(status_info, "error_count", "0")),
         vdev_count: length(vdevs),
-        degraded_vdev_count: Enum.count(vdevs, &(&1["state"] != "ONLINE")),
-        last_scrub_end: get_in(status_info, ["scan", "end_time"])
+        degraded_vdev_count: Enum.count(vdevs, &(&1.state != "ONLINE")),
+        pool_type: derive_pool_type(vdevs),
+        scan_function: get_in(status_info, ["scan", "function"]),
+        scan_state: get_in(status_info, ["scan", "state"]),
+        last_scrub_end: get_in(status_info, ["scan", "end_time"]),
+        vdevs: vdevs
       }
     end)
   end
 
+  defp vdev_summary(v) do
+    %{
+      name: Map.get(v, "name"),
+      type: Map.get(v, "vdev_type"),
+      state: Map.get(v, "state"),
+      read_errors: to_int(Map.get(v, "read_errors", "0")),
+      write_errors: to_int(Map.get(v, "write_errors", "0")),
+      checksum_errors: to_int(Map.get(v, "checksum_errors", "0"))
+    }
+  end
+
+  @data_vdev_types ~w(mirror raidz1 raidz2 raidz3 disk)
+  @special_vdev_types ~w(log cache spare dedup special)
+
+  defp derive_pool_type(vdevs) do
+    data_types =
+      vdevs
+      |> Enum.map(& &1.type)
+      |> Enum.reject(&(&1 in @special_vdev_types))
+      |> Enum.uniq()
+
+    case data_types do
+      [] -> "unknown"
+      ["disk"] -> "stripe"
+      [t] when t in @data_vdev_types -> t
+      _ -> "mixed"
+    end
+  end
+
   defp summarize_datasets(nil), do: []
 
   defp summarize_datasets(%{"datasets" => datasets}) do
@@ -129,7 +176,15 @@ defmodule ProxmoxAgent.Collectors.Zfs do
   end
 
   defp to_int(v) when is_integer(v), do: v
-  defp to_int(v) when is_binary(v), do: String.to_integer(v)
+
+  defp to_int(v) when is_binary(v) do
+    case Integer.parse(v) do
+      {n, _} -> n
+      :error -> 0
+    end
+  end
+
+  defp to_int(_), do: 0
 
   defp max_or_nil([]), do: nil
   defp max_or_nil(list), do: Enum.max(list)

agent/test/fixtures/zfs/zpool_status.json

@@ -26,7 +26,7 @@
       "state": "DEGRADED",
       "scan": {
         "function": "scrub",
-        "state": "FINISHED",
+        "state": "SCANNING",
         "end_time": "Tue Mar 01 08:00:00 2026"
       },
       "error_count": "2",

agent/test/proxmox_agent/collectors/zfs_test.exs

@@ -32,10 +32,19 @@ defmodule ProxmoxAgent.Collectors.ZfsTest do
       assert rpool.size_bytes == 500_000_000_000
       assert rpool.error_count == 0
       assert rpool.degraded_vdev_count == 0
+      assert rpool.pool_type == "mirror"
+      assert rpool.scan_function == "scrub"
+      assert rpool.scan_state == "FINISHED"
+      assert [%{name: "mirror-0", type: "mirror", state: "ONLINE",
+                read_errors: 0, write_errors: 0, checksum_errors: 0}] = rpool.vdevs
 
       assert tank.health == "DEGRADED"
       assert tank.error_count == 2
       assert tank.degraded_vdev_count == 1
+      assert tank.pool_type == "raidz2"
+      assert tank.scan_state == "SCANNING"
+      assert [%{name: "raidz2-0", type: "raidz2", state: "DEGRADED",
+                checksum_errors: 2}] = tank.vdevs
     end
 
     test "populates errors list when zpool fails" do
@@ -44,6 +53,94 @@ defmodule ProxmoxAgent.Collectors.ZfsTest do
       assert sample.pools == []
       assert length(sample.errors) >= 1
     end
+
+    test "classifies pool_type for stripe, mixed, and special vdevs" do
+      list_json =
+        Jason.encode!(%{
+          "pools" => %{
+            "stripe" => %{"name" => "stripe", "size" => 1, "alloc" => 0, "free" => 1,
+                         "frag" => 0, "cap" => 0, "health" => "ONLINE"},
+            "mixed" => %{"name" => "mixed", "size" => 1, "alloc" => 0, "free" => 1,
+                        "frag" => 0, "cap" => 0, "health" => "ONLINE"},
+            "mirror_with_log" => %{"name" => "mirror_with_log", "size" => 1, "alloc" => 0, "free" => 1,
+                                    "frag" => 0, "cap" => 0, "health" => "ONLINE"}
+          }
+        })
+
+      vdev = fn name, type ->
+        {name, %{"name" => name, "vdev_type" => type, "state" => "ONLINE",
+                 "read_errors" => "0", "write_errors" => "0", "checksum_errors" => "0"}}
+      end
+
+      status_json =
+        Jason.encode!(%{
+          "pools" => %{
+            "stripe" => %{
+              "name" => "stripe", "state" => "ONLINE", "error_count" => "0",
+              "vdevs" => Map.new([vdev.("sda", "disk"), vdev.("sdb", "disk")])
+            },
+            "mixed" => %{
+              "name" => "mixed", "state" => "ONLINE", "error_count" => "0",
+              "vdevs" => Map.new([vdev.("mirror-0", "mirror"), vdev.("raidz1-1", "raidz1")])
+            },
+            "mirror_with_log" => %{
+              "name" => "mirror_with_log", "state" => "ONLINE", "error_count" => "0",
+              "vdevs" => Map.new([vdev.("mirror-0", "mirror"), vdev.("log-0", "log")])
+            }
+          }
+        })
+
+      runner = fn
+        "zpool", ["list" | _] -> {:ok, list_json}
+        "zpool", ["status" | _] -> {:ok, status_json}
+      end
+
+      sample = Zfs.collect_pools(runner: runner)
+      by_name = Map.new(sample.pools, &{&1.name, &1})
+
+      assert by_name["stripe"].pool_type == "stripe"
+      assert by_name["mixed"].pool_type == "mixed"
+      assert by_name["mirror_with_log"].pool_type == "mirror"
+      # log vdev is retained in the per-pool vdevs list even though it's ignored for layout classification
+      assert Enum.any?(by_name["mirror_with_log"].vdevs, &(&1.type == "log"))
+    end
+
+    test "tolerates nil and non-integer error counters" do
+      list_json =
+        Jason.encode!(%{
+          "pools" => %{
+            "weird" => %{"name" => "weird", "size" => 1, "alloc" => 0, "free" => 1,
+                        "frag" => 0, "cap" => 0, "health" => "ONLINE"}
+          }
+        })
+
+      status_json =
+        Jason.encode!(%{
+          "pools" => %{
+            "weird" => %{
+              "name" => "weird", "state" => "ONLINE", "error_count" => nil,
+              "vdevs" => %{
+                "disk-0" => %{"name" => "disk-0", "vdev_type" => "disk", "state" => "ONLINE",
+                              "read_errors" => nil, "write_errors" => "abc",
+                              "checksum_errors" => "0"}
+              }
+            }
+          }
+        })
+
+      runner = fn
+        "zpool", ["list" | _] -> {:ok, list_json}
+        "zpool", ["status" | _] -> {:ok, status_json}
+      end
+
+      sample = Zfs.collect_pools(runner: runner)
+      [pool] = sample.pools
+      assert pool.error_count == 0
+      [vdev] = pool.vdevs
+      assert vdev.read_errors == 0
+      assert vdev.write_errors == 0
+      assert vdev.checksum_errors == 0
+    end
   end
 
   describe "collect_datasets/1" do

docs/superpowers/plans/2026-04-22-zfs-pool-detail.md

@@ -0,0 +1,532 @@
+# ZFS Pool Detail Implementation Plan
+
+> **For agentic workers:** REQUIRED SUB-SKILL: Use superpowers:subagent-driven-development (recommended) or superpowers:executing-plans to implement this plan task-by-task. Steps use checkbox (`- [ ]`) syntax for tracking.
+
+**Goal:** Show type, total/used/free size, capacity bar, and scan state per ZFS pool on the host detail page — a simple at-a-glance view with no drill-down yet.
+
+**Architecture:** Extend the existing agent collector (`ProxmoxAgent.Collectors.Zfs.collect_pools/1`) to derive `pool_type`, `scan_function`, `scan_state`, and a compact `vdevs` list from the already-fetched `zpool status -j --json-flat-vdevs` JSON. No new shell-outs. The Phoenix channel stores pool payloads as opaque JSON, so server/DB layers need no change. The host detail LiveView renders a new compact per-pool block using the enriched fields plus a thin capacity bar driven by existing `capacity_percent` thresholds.
+
+**Tech Stack:** Elixir / Phoenix LiveView, ExUnit, existing `assets/css/app.css`. Design doc: `docs/superpowers/specs/2026-04-22-zfs-pool-detail-design.md`.
+
+---
+
+## File Structure
+
+**Modify**
+- `agent/lib/proxmox_agent/collectors/zfs.ex` — extend `merge_pools/2` to emit `pool_type`, `scan_function`, `scan_state`, and `vdevs` list.
+- `agent/test/proxmox_agent/collectors/zfs_test.exs` — extend existing assertions, add new test cases for stripe, mixed, and ignored special vdev types.
+- `server/lib/server_web/live/host_detail_live.ex` — replace the pool row markup (current lines 69–86), add `capbar_level/1`, `pool_scrub_line/1`, and `pool_layout/1` helpers.
+- `server/assets/css/app.css` — add `.capbar` rules.
+- `server/test/server_web/live/host_detail_live_test.exs` — extend the fast-sample pool fixture with the new fields and add assertions.
+
+**No new files.** All changes are additive and land inside existing modules.
+
+---
+
+## Task 1: Agent collector — pool_type, scan state, vdev list
+
+**Files:**
+- Modify: `agent/lib/proxmox_agent/collectors/zfs.ex`
+- Modify: `agent/test/proxmox_agent/collectors/zfs_test.exs`
+- Modify: `agent/test/fixtures/zfs/zpool_status.json`
+
+### - [ ] Step 1: Add per-vdev error counters to the fixture so tests can assert on them
+
+Replace `agent/test/fixtures/zfs/zpool_status.json` with:
+
+```json
+{
+  "output_version": { "command": "zpool status", "vers_major": 0, "vers_minor": 1 },
+  "pools": {
+    "rpool": {
+      "name": "rpool",
+      "state": "ONLINE",
+      "scan": {
+        "function": "scrub",
+        "state": "FINISHED",
+        "end_time": "Sat Apr 19 02:00:00 2026"
+      },
+      "error_count": "0",
+      "vdevs": {
+        "mirror-0": {
+          "name": "mirror-0",
+          "vdev_type": "mirror",
+          "state": "ONLINE",
+          "read_errors": "0",
+          "write_errors": "0",
+          "checksum_errors": "0"
+        }
+      }
+    },
+    "tank": {
+      "name": "tank",
+      "state": "DEGRADED",
+      "scan": {
+        "function": "scrub",
+        "state": "SCANNING",
+        "end_time": "Tue Mar 01 08:00:00 2026"
+      },
+      "error_count": "2",
+      "vdevs": {
+        "raidz2-0": {
+          "name": "raidz2-0",
+          "vdev_type": "raidz2",
+          "state": "DEGRADED",
+          "read_errors": "0",
+          "write_errors": "0",
+          "checksum_errors": "2"
+        }
+      }
+    }
+  }
+}
+```
+
+(The only change from the current fixture is `"tank"`'s `scan.state` → `"SCANNING"` so a scrub-in-progress case is covered.)
+
+### - [ ] Step 2: Extend the existing fixture-based test with new field assertions
+
+Edit `agent/test/proxmox_agent/collectors/zfs_test.exs`. Inside `describe "collect_pools/1"`, replace the `"returns a summary per pool"` test body with:
+
+```elixir
+test "returns a summary per pool" do
+  sample = Zfs.collect_pools(runner: fake_runner())
+  assert is_list(sample.pools)
+  assert length(sample.pools) == 2
+  rpool = Enum.find(sample.pools, &(&1.name == "rpool"))
+  tank = Enum.find(sample.pools, &(&1.name == "tank"))
+
+  assert rpool.health == "ONLINE"
+  assert rpool.capacity_percent == 40
+  assert rpool.fragmentation_percent == 17
+  assert rpool.size_bytes == 500_000_000_000
+  assert rpool.error_count == 0
+  assert rpool.degraded_vdev_count == 0
+  assert rpool.pool_type == "mirror"
+  assert rpool.scan_function == "scrub"
+  assert rpool.scan_state == "FINISHED"
+  assert [%{name: "mirror-0", type: "mirror", state: "ONLINE",
+            read_errors: 0, write_errors: 0, checksum_errors: 0}] = rpool.vdevs
+
+  assert tank.health == "DEGRADED"
+  assert tank.error_count == 2
+  assert tank.degraded_vdev_count == 1
+  assert tank.pool_type == "raidz2"
+  assert tank.scan_state == "SCANNING"
+  assert [%{name: "raidz2-0", type: "raidz2", state: "DEGRADED",
+            checksum_errors: 2}] = tank.vdevs
+end
+```
+
+### - [ ] Step 3: Run tests — expect FAIL
+
+Run: `cd agent && mix test test/proxmox_agent/collectors/zfs_test.exs`
+
+Expected: the `"returns a summary per pool"` test fails because `:pool_type`, `:scan_function`, `:scan_state`, and `:vdevs` are not yet on the pool map.
+
+### - [ ] Step 4: Implement the new fields in the collector
+
+Edit `agent/lib/proxmox_agent/collectors/zfs.ex`. Update the `@type pool_summary` and `merge_pools/2` function as follows:
+
+```elixir
+  @type vdev_summary :: %{
+          name: String.t(),
+          type: String.t(),
+          state: String.t(),
+          read_errors: non_neg_integer(),
+          write_errors: non_neg_integer(),
+          checksum_errors: non_neg_integer()
+        }
+
+  @type pool_summary :: %{
+          name: String.t(),
+          health: String.t(),
+          size_bytes: non_neg_integer(),
+          allocated_bytes: non_neg_integer(),
+          free_bytes: non_neg_integer(),
+          fragmentation_percent: non_neg_integer(),
+          capacity_percent: non_neg_integer(),
+          error_count: non_neg_integer(),
+          vdev_count: non_neg_integer(),
+          degraded_vdev_count: non_neg_integer(),
+          pool_type: String.t(),
+          scan_function: String.t() | nil,
+          scan_state: String.t() | nil,
+          last_scrub_end: String.t() | nil,
+          vdevs: [vdev_summary()]
+        }
+```
+
+Replace the body of `merge_pools(%{"pools" => list_pools}, %{"pools" => status_pools})` with:
+
+```elixir
+  defp merge_pools(%{"pools" => list_pools}, %{"pools" => status_pools}) do
+    Enum.map(list_pools, fn {name, list_info} ->
+      status_info = Map.get(status_pools, name, %{})
+      raw_vdevs = Map.get(status_info, "vdevs", %{}) |> Map.values()
+      vdevs = Enum.map(raw_vdevs, &vdev_summary/1)
+
+      %{
+        name: name,
+        health: Map.get(list_info, "health"),
+        size_bytes: Map.get(list_info, "size", 0),
+        allocated_bytes: Map.get(list_info, "alloc", 0),
+        free_bytes: Map.get(list_info, "free", 0),
+        fragmentation_percent: Map.get(list_info, "frag", 0),
+        capacity_percent: Map.get(list_info, "cap", 0),
+        error_count: to_int(Map.get(status_info, "error_count", "0")),
+        vdev_count: length(vdevs),
+        degraded_vdev_count: Enum.count(vdevs, &(&1.state != "ONLINE")),
+        pool_type: derive_pool_type(vdevs),
+        scan_function: get_in(status_info, ["scan", "function"]),
+        scan_state: get_in(status_info, ["scan", "state"]),
+        last_scrub_end: get_in(status_info, ["scan", "end_time"]),
+        vdevs: vdevs
+      }
+    end)
+  end
+
+  defp vdev_summary(v) do
+    %{
+      name: Map.get(v, "name"),
+      type: Map.get(v, "vdev_type"),
+      state: Map.get(v, "state"),
+      read_errors: to_int(Map.get(v, "read_errors", "0")),
+      write_errors: to_int(Map.get(v, "write_errors", "0")),
+      checksum_errors: to_int(Map.get(v, "checksum_errors", "0"))
+    }
+  end
+
+  @data_vdev_types ~w(mirror raidz1 raidz2 raidz3 disk)
+  @special_vdev_types ~w(log cache spare dedup special)
+
+  defp derive_pool_type(vdevs) do
+    data_types =
+      vdevs
+      |> Enum.map(& &1.type)
+      |> Enum.reject(&(&1 in @special_vdev_types))
+      |> Enum.uniq()
+
+    case data_types do
+      [] -> "unknown"
+      ["disk"] -> "stripe"
+      [t] when t in @data_vdev_types -> t
+      _ -> "mixed"
+    end
+  end
+```
+
+### - [ ] Step 5: Run tests — expect PASS
+
+Run: `cd agent && mix test test/proxmox_agent/collectors/zfs_test.exs`
+
+Expected: all tests pass.
+
+### - [ ] Step 6: Commit
+
+```bash
+git add agent/lib/proxmox_agent/collectors/zfs.ex \
+        agent/test/proxmox_agent/collectors/zfs_test.exs \
+        agent/test/fixtures/zfs/zpool_status.json
+git commit -m "feat(agent): enrich zpool summary with type, scan state, vdev list"
+```
+
+---
+
+## Task 2: Agent collector — stripe, mixed, and special-vdev coverage
+
+**Files:**
+- Modify: `agent/test/proxmox_agent/collectors/zfs_test.exs`
+
+### - [ ] Step 1: Add test for plain stripe, mixed layout, and special-vdev filtering
+
+Append this block inside `describe "collect_pools/1"` in `agent/test/proxmox_agent/collectors/zfs_test.exs`:
+
+```elixir
+  test "classifies pool_type for stripe, mixed, and special vdevs" do
+    list_json =
+      Jason.encode!(%{
+        "pools" => %{
+          "stripe" => %{"name" => "stripe", "size" => 1, "alloc" => 0, "free" => 1,
+                       "frag" => 0, "cap" => 0, "health" => "ONLINE"},
+          "mixed" => %{"name" => "mixed", "size" => 1, "alloc" => 0, "free" => 1,
+                      "frag" => 0, "cap" => 0, "health" => "ONLINE"},
+          "mirror_with_log" => %{"name" => "mirror_with_log", "size" => 1, "alloc" => 0, "free" => 1,
+                                  "frag" => 0, "cap" => 0, "health" => "ONLINE"}
+        }
+      })
+
+    vdev = fn name, type ->
+      {name, %{"name" => name, "vdev_type" => type, "state" => "ONLINE",
+               "read_errors" => "0", "write_errors" => "0", "checksum_errors" => "0"}}
+    end
+
+    status_json =
+      Jason.encode!(%{
+        "pools" => %{
+          "stripe" => %{
+            "name" => "stripe", "state" => "ONLINE", "error_count" => "0",
+            "vdevs" => Map.new([vdev.("sda", "disk"), vdev.("sdb", "disk")])
+          },
+          "mixed" => %{
+            "name" => "mixed", "state" => "ONLINE", "error_count" => "0",
+            "vdevs" => Map.new([vdev.("mirror-0", "mirror"), vdev.("raidz1-1", "raidz1")])
+          },
+          "mirror_with_log" => %{
+            "name" => "mirror_with_log", "state" => "ONLINE", "error_count" => "0",
+            "vdevs" => Map.new([vdev.("mirror-0", "mirror"), vdev.("log-0", "log")])
+          }
+        }
+      })
+
+    runner = fn
+      "zpool", ["list" | _] -> {:ok, list_json}
+      "zpool", ["status" | _] -> {:ok, status_json}
+    end
+
+    sample = Zfs.collect_pools(runner: runner)
+    by_name = Map.new(sample.pools, &{&1.name, &1})
+
+    assert by_name["stripe"].pool_type == "stripe"
+    assert by_name["mixed"].pool_type == "mixed"
+    assert by_name["mirror_with_log"].pool_type == "mirror"
+    # log vdev is retained in the per-pool vdevs list even though it's ignored for layout classification
+    assert Enum.any?(by_name["mirror_with_log"].vdevs, &(&1.type == "log"))
+  end
+```
+
+### - [ ] Step 2: Run the new test — expect PASS (collector already implements the logic)
+
+Run: `cd agent && mix test test/proxmox_agent/collectors/zfs_test.exs`
+
+Expected: all tests pass, including the new case.
+
+### - [ ] Step 3: Commit
+
+```bash
+git add agent/test/proxmox_agent/collectors/zfs_test.exs
+git commit -m "test(agent): cover stripe, mixed, and special-vdev pool_type classification"
+```
+
+---
+
+## Task 3: UI — capacity bar CSS
+
+**Files:**
+- Modify: `server/assets/css/app.css`
+
+### - [ ] Step 1: Add `.capbar` rules after the existing `.pool-row` block
+
+In `server/assets/css/app.css`, locate the `.pool-row` rules (around lines 249–258) and insert the following immediately after them:
+
+```css
+.capbar {
+  height: 4px;
+  background: var(--panel-2);
+  border-radius: 2px;
+  overflow: hidden;
+  margin: 0.25rem 0 0.4rem;
+}
+.capbar > span {
+  display: block;
+  height: 100%;
+  background: var(--ok);
+  transition: width 0.3s ease;
+}
+.capbar[data-level="warn"] > span { background: var(--warn); }
+.capbar[data-level="crit"] > span { background: var(--crit); }
+
+.pool-block {
+  padding: 0.6rem 0.9rem;
+  border-bottom: 1px solid var(--border);
+}
+.pool-block:last-child { border-bottom: none; }
+.pool-block .head {
+  display: flex;
+  justify-content: space-between;
+  align-items: baseline;
+  gap: 0.6rem;
+}
+.pool-block .head .layout { color: var(--muted); font-size: 0.8rem; margin-left: 0.5rem; }
+.pool-block .sizes { font-family: var(--mono); font-size: 0.78rem; color: var(--fg); }
+.pool-block .details { color: var(--muted); font-family: var(--mono); font-size: 0.78rem; }
+```
+
+### - [ ] Step 2: Commit
+
+```bash
+git add server/assets/css/app.css
+git commit -m "style(ui): capacity bar and per-pool block styles"
+```
+
+---
+
+## Task 4: UI — render per-pool block with type, capacity bar, sizes, scrub state
+
+**Files:**
+- Modify: `server/lib/server_web/live/host_detail_live.ex`
+- Modify: `server/test/server_web/live/host_detail_live_test.exs`
+
+### - [ ] Step 1: Extend the LiveView test fixture with the new fields and add assertions
+
+In `server/test/server_web/live/host_detail_live_test.exs`, replace the `"zfs_pools"` block inside the `fast` fixture (currently ~lines 15–25) with:
+
+```elixir
+      "zfs_pools" => %{
+        "pools" => [
+          %{
+            "name" => "rpool",
+            "health" => "ONLINE",
+            "pool_type" => "mirror",
+            "size_bytes" => 500_000_000_000,
+            "allocated_bytes" => 200_000_000_000,
+            "free_bytes" => 300_000_000_000,
+            "capacity_percent" => 40,
+            "fragmentation_percent" => 17,
+            "error_count" => 0,
+            "vdev_count" => 1,
+            "degraded_vdev_count" => 0,
+            "scan_function" => "scrub",
+            "scan_state" => "FINISHED",
+            "last_scrub_end" => "Sat Apr 19 02:00:00 2026",
+            "vdevs" => [
+              %{"name" => "mirror-0", "type" => "mirror", "state" => "ONLINE",
+                "read_errors" => 0, "write_errors" => 0, "checksum_errors" => 0}
+            ]
+          }
+        ]
+      },
+```
+
+Then in the `"renders sections..."` test, after the existing assertions, add:
+
+```elixir
+    assert html =~ "mirror"
+    assert html =~ "465.7 GB"       # size_bytes formatted
+    assert html =~ "186.3 GB"       # allocated_bytes formatted
+    assert html =~ "279.4 GB"       # free_bytes formatted
+    assert html =~ "capbar"
+    assert html =~ "scrub"
+```
+
+(Byte-to-`format_bytes/1` values: 500 GB decimal → 465.7 GiB; 200 GB → 186.3 GiB; 300 GB → 279.4 GiB. The helper divides by 1024 per step.)
+
+### - [ ] Step 2: Run LiveView test — expect FAIL
+
+Run: `cd server && mix test test/server_web/live/host_detail_live_test.exs`
+
+Expected: `"renders sections..."` fails on the new assertions (`"mirror"`, sizes, `"capbar"`).
+
+### - [ ] Step 3: Replace the pool-rendering block in the LiveView
+
+In `server/lib/server_web/live/host_detail_live.ex`, replace the panel that renders ZFS pools (current lines 65–87, the `<div class="panel">` containing `<header><span>ZFS pools</span>` down through its closing `</div>`) with:
+
+```heex
+      <div class="panel">
+        <header><span>ZFS pools</span><span class="mono">{length(pools(@fast))}</span></header>
+        <div class="body tight">
+          <div :if={pools(@fast) == []} class="empty">No data.</div>
+          <div :for={pool <- pools(@fast)} class="pool-block">
+            <div class="head">
+              <div>
+                <span class="mono" style="color: var(--fg-bright); font-weight: 600;">{pool["name"]}</span>
+                <span class="layout">{pool_layout(pool)}</span>
+              </div>
+              <span class="badge" style={pool_badge_style(pool["health"])}>{pool["health"]}</span>
+            </div>
+
+            <div class="capbar" data-level={capbar_level(pool["capacity_percent"])}>
+              <span style={"width: #{pool["capacity_percent"] || 0}%"}></span>
+            </div>
+
+            <div class="sizes">
+              used {format_bytes(pool["allocated_bytes"] || 0)} ·
+              free {format_bytes(pool["free_bytes"] || 0)} ·
+              total {format_bytes(pool["size_bytes"] || 0)}
+              <span class="muted">({pool["capacity_percent"] || 0}%)</span>
+            </div>
+
+            <div class="details">
+              frag {pool["fragmentation_percent"] || 0}% ·
+              err {pool["error_count"] || 0} ·
+              vdevs {pool["vdev_count"] || 0} (deg {pool["degraded_vdev_count"] || 0}) ·
+              {pool_scrub_line(pool)}
+            </div>
+
+            <div :for={v <- degraded_vdevs(pool)} class="callout err" style="margin-top: 0.4rem;">
+              {v["name"]} {v["state"]} · r={v["read_errors"]} w={v["write_errors"]} cksum={v["checksum_errors"]}
+            </div>
+          </div>
+        </div>
+      </div>
+```
+
+Then add these helper functions near the other private helpers (after `pool_badge_style/1`):
+
+```elixir
+  defp pool_layout(pool) do
+    case pool["pool_type"] do
+      nil -> "—"
+      "" -> "—"
+      t -> t
+    end
+  end
+
+  defp capbar_level(cap) when is_number(cap) and cap >= 90, do: "crit"
+  defp capbar_level(cap) when is_number(cap) and cap >= 80, do: "warn"
+  defp capbar_level(_), do: "ok"
+
+  defp pool_scrub_line(%{"scan_state" => "SCANNING"}), do: "scrub scanning"
+
+  defp pool_scrub_line(%{"scan_state" => "FINISHED", "last_scrub_end" => end_time})
+       when is_binary(end_time) and end_time != "",
+       do: "scrub #{end_time}"
+
+  defp pool_scrub_line(%{"last_scrub_end" => end_time}) when is_binary(end_time) and end_time != "",
+    do: "scrub #{end_time}"
+
+  defp pool_scrub_line(_), do: "scrub never"
+
+  defp degraded_vdevs(pool) do
+    (pool["vdevs"] || [])
+    |> Enum.filter(fn v -> Map.get(v, "state") not in [nil, "ONLINE"] end)
+  end
+```
+
+### - [ ] Step 4: Run LiveView test — expect PASS
+
+Run: `cd server && mix test test/server_web/live/host_detail_live_test.exs`
+
+Expected: all tests pass.
+
+### - [ ] Step 5: Run the full server suite to catch regressions
+
+Run: `cd server && mix test`
+
+Expected: all tests pass.
+
+### - [ ] Step 6: Run the full agent suite to catch regressions
+
+Run: `cd agent && mix test`
+
+Expected: all tests pass.
+
+### - [ ] Step 7: Manual visual check (dev server)
+
+Start the server locally (`cd server && mix phx.server`), log in, open a host detail page with live agent data, and confirm:
+
+- Each pool shows `name  pool_type` on line 1 with the health badge on the right.
+- The capacity bar renders at the correct width and turns yellow/red at 80% / 90%.
+- `used / free / total` line shows bytes formatted like `200.0 GB`.
+- The `details` line shows frag/err/vdevs and a scrub label (`scrub finished …`, `scrub scanning`, or `scrub never`).
+- Degraded pools list each non-ONLINE vdev in a red `.callout.err` line; ONLINE pools don't.
+
+If the manual check reveals a rendering issue, fix it in `host_detail_live.ex` and re-run `cd server && mix test`.
+
+### - [ ] Step 8: Commit
+
+```bash
+git add server/lib/server_web/live/host_detail_live.ex \
+        server/test/server_web/live/host_detail_live_test.exs
+git commit -m "feat(ui): detailed per-pool block with type, capacity bar, scrub state"
+```

docs/superpowers/specs/2026-04-22-zfs-pool-detail-design.md

@@ -0,0 +1,159 @@
+# ZFS Pool Detail — Design
+
+Date: 2026-04-22
+Status: approved (pending implementation)
+
+## Problem
+
+The host detail view renders a compact row per ZFS pool today (`server/lib/server_web/live/host_detail_live.ex:67`):
+
+```
+rpool [ONLINE]
+cap 0% · frag 0% · err 0 · vdevs 4 (deg 0)                          scrub never
+```
+
+This hides information the user needs at first glance:
+
+- Total / used / free size (bytes are already collected but never rendered).
+- Pool layout (mirror / raidz1 / raidz2 / stripe / mixed) — not collected.
+- Scan state — only `end_time` is kept, so an in-progress scrub looks like a finished one.
+
+The original concept doc calls for "Health, Capacity-Bar, Fragmentation, Error-Counters, Scrub-Info, vdev-Liste" per pool (`proxmox-monitor-konzept.md:227`). We never finished that.
+
+## Goal
+
+One compact block per pool that answers at a glance: *is it healthy, what layout is it, how full is it, is a scrub running*. No drill-down yet.
+
+## Scope
+
+In scope:
+
+1. Agent collector enrichment — derive `pool_type`, keep vdev summary list, keep scan function/state. No new shell-outs; `zpool status -j --json-flat-vdevs --json-int` already returns all of this.
+2. Host detail LiveView — replace the current single-line pool row with a richer compact block (see layout below).
+3. Capacity bar styling in `assets/css/app.css`.
+4. Tests — extend `agent/test/proxmox_agent/collectors/zfs_test.exs` fixtures and assertions for the new fields.
+
+Out of scope (YAGNI):
+
+- Drill-down view with per-vdev disk state, resilver progress bars, or scan history.
+- Persistence schema changes — payload is stored as JSON blob; adding keys is additive.
+- Storage/dataset/VM panel changes — separate conversation.
+
+## Agent changes
+
+### Collector output
+
+Extend `ProxmoxAgent.Collectors.Zfs.pool_summary` with three fields:
+
+```elixir
+%{
+  # existing fields unchanged:
+  name:, health:, size_bytes:, allocated_bytes:, free_bytes:,
+  fragmentation_percent:, capacity_percent:, error_count:,
+  vdev_count:, degraded_vdev_count:, last_scrub_end:,
+
+  # new:
+  pool_type: String.t(),            # "mirror" | "raidz1" | "raidz2" | "raidz3" | "stripe" | "mixed"
+  scan_function: String.t() | nil,  # "scrub" | "resilver" | nil
+  scan_state: String.t() | nil,     # "SCANNING" | "FINISHED" | "CANCELED" | nil
+  vdevs: [%{name: String.t(), type: String.t(), state: String.t(),
+            read_errors: non_neg_integer(), write_errors: non_neg_integer(),
+            checksum_errors: non_neg_integer()}]
+}
+```
+
+### Derivation rules
+
+`pool_type` is derived from the set of `vdev_type` values across top-level vdevs:
+
+- All vdevs the same type → that type (`"mirror"`, `"raidz1"`, `"raidz2"`, `"raidz3"`).
+- All vdevs are `disk` (plain top-level disk with no redundancy) → `"stripe"`.
+- Anything else → `"mixed"`.
+
+Special vdev types (`log`, `cache`, `spare`, `dedup`, `special`) are ignored for layout classification — they don't change the data redundancy story. They are still included in the `vdevs` list.
+
+`scan_function` / `scan_state` read `get_in(status_info, ["scan", "function" | "state"])`.
+
+Per-vdev numeric fields (`read_errors`, `write_errors`, `checksum_errors`) are parsed the same way `error_count` already is (string or int tolerant).
+
+### Tests
+
+`agent/test/fixtures/zfs/zpool_status.json` already has a mirror and a raidz2 pool; extend assertions in `zfs_test.exs`:
+
+- `rpool.pool_type == "mirror"`
+- `tank.pool_type == "raidz2"`
+- `rpool.scan_state == "FINISHED"`
+- `rpool.vdevs` has length 1 with `type: "mirror"`, `state: "ONLINE"`
+
+Add one new fixture-free unit test covering the `"stripe"` and `"mixed"` branches by injecting a synthetic runner.
+
+## Server changes
+
+None in the collector pipeline. The channel handler already stores the whole `zfs_pools.pools` list as JSON (`server/lib/server_web/channels/host_channel.ex` — to confirm in plan) and the LiveView reads it with `get_in/2`. New keys flow through automatically.
+
+## UI changes
+
+### Layout
+
+Replace the current `.pool-row` flex block in `host_detail_live.ex:69-86` with a per-pool compact block:
+
+```
+rpool  mirror                                               [ONLINE]
+████████░░░░░░░░░░░░░░░░░░░░░░░░░░░░  40%
+used 200.0 GB  ·  free 300.0 GB  ·  total 500.0 GB
+frag 17%  ·  err 0  ·  vdevs 1 (deg 0)  ·  scrub finished 2026-04-19
+```
+
+Element mapping:
+
+- Line 1: pool name (bright mono, bold) · pool_type (muted) · health badge (right).
+- Line 2: capacity bar (div with width % + background color keyed to capacity thresholds).
+- Line 3: used / free / total — rendered with the existing `format_bytes/1` helper.
+- Line 4: the existing compact details line, plus scrub state — `scrub scanning` / `scrub finished <date>` / `scrub never`.
+
+### Capacity bar
+
+CSS in `server/assets/css/app.css`:
+
+```css
+.capbar {
+  height: 4px; background: var(--panel-2); border-radius: 2px;
+  overflow: hidden; margin: 0.25rem 0;
+}
+.capbar > span { display: block; height: 100%; background: var(--ok); }
+.capbar[data-level="warn"] > span { background: var(--warn); }
+.capbar[data-level="crit"] > span { background: var(--crit); }
+```
+
+Thresholds (matching the concept doc's thresholds at `proxmox-monitor-konzept.md:218-219`):
+
+- `cap >= 90` → `data-level="crit"`
+- `cap >= 80` → `data-level="warn"`
+- else → default (ok green).
+
+### Degraded pool callout
+
+For ONLINE pools with `degraded_vdev_count == 0`, do not render per-vdev detail — keep it simple. For anything else, render one line per non-ONLINE vdev below the detail line:
+
+```
+!  mirror-1  DEGRADED  r=0 w=0 cksum=12
+```
+
+Styled with the existing `.callout.err` class.
+
+### Scrub rendering
+
+- `scan_state == "SCANNING"` → `"scrub scanning"` (no date).
+- `scan_state == "FINISHED"` and `last_scrub_end` present → `"scrub #{format_date(last_scrub_end)}"`.
+- Otherwise → `"scrub never"`.
+
+`last_scrub_end` is a string like `"Sat Apr 19 02:00:00 2026"` — keep as-is or reformat to `YYYY-MM-DD` with a tiny helper (strptime isn't stdlib-trivial in Elixir; simplest: split on whitespace and reorder). Accept "as-is" if reformatting is ugly.
+
+## Risks
+
+- ZFS JSON output has changed shape between OpenZFS releases. The concept doc requires `OpenZFS 2.3+`. Agent code tolerates missing keys via `Map.get/3` defaults — keep that discipline.
+- `zpool status --json-flat-vdevs` flattens nested mirrors-of-mirrors. Top-level vdevs are keyed by name; pool_type derivation inspects only top-level entries (no child vdev walking needed in the flat form).
+
+## Rollout
+
+Additive collector changes + additive UI. No DB migration, no breaking payload change. Old agents without the new fields render the "graceful degraded" path: `pool_type` shows as `—`, scrub line falls back to `never`, capacity bar still renders from existing bytes.

server/assets/css/app.css

@@ -246,16 +246,36 @@ hr { border: 0; border-top: 1px solid var(--border); margin: 0; }
 .kv dt { color: var(--muted); }
 .kv dd { margin: 0; font-family: var(--mono); color: var(--fg-bright); }
 
-.pool-row {
+.capbar {
+  height: 4px;
+  background: var(--panel-2);
+  border-radius: 2px;
+  overflow: hidden;
+  margin: 0.25rem 0 0.4rem;
+}
+.capbar > span {
+  display: block;
+  height: 100%;
+  background: var(--ok);
+  transition: width 0.3s ease;
+}
+.capbar[data-level="warn"] > span { background: var(--warn); }
+.capbar[data-level="crit"] > span { background: var(--crit); }
+
+.pool-block {
+  padding: 0.6rem 0.9rem;
+  border-bottom: 1px solid var(--border);
+}
+.pool-block:last-child { border-bottom: none; }
+.pool-block .head {
   display: flex;
   justify-content: space-between;
-  padding: 0.45rem 0;
-  border-bottom: 1px solid var(--border);
-  gap: 0.8rem;
-  font-size: 0.85rem;
+  align-items: baseline;
+  gap: 0.6rem;
 }
-.pool-row:last-child { border-bottom: none; }
-.pool-row .details { color: var(--muted); font-family: var(--mono); font-size: 0.78rem; }
+.pool-block .head .layout { color: var(--muted); font-size: 0.8rem; margin-left: 0.5rem; }
+.pool-block .sizes { font-family: var(--mono); font-size: 0.78rem; color: var(--fg); }
+.pool-block .details { color: var(--muted); font-family: var(--mono); font-size: 0.78rem; }
 
 /* --- callouts ------------------------------------------------------------ */
 .callout {

server/lib/server_web/live/host_detail_live.ex

@@ -66,21 +66,35 @@ defmodule ServerWeb.HostDetailLive do
         <header><span>ZFS pools</span><span class="mono">{length(pools(@fast))}</span></header>
         <div class="body tight">
           <div :if={pools(@fast) == []} class="empty">No data.</div>
-          <div :for={pool <- pools(@fast)} class="pool-row" style="padding: 0.6rem 0.9rem;">
+          <div :for={pool <- pools(@fast)} class="pool-block">
+            <div class="head">
               <div>
-              <span class="mono" style="color: var(--fg-bright); font-weight: 600;">
-                {pool["name"]}
-              </span>
+                <span class="mono" style="color: var(--fg-bright); font-weight: 600;">{pool["name"]}</span>
+                <span class="layout">{pool_layout(pool)}</span>
+              </div>
               <span class="badge" style={pool_badge_style(pool["health"])}>{pool["health"]}</span>
+            </div>
+
+            <div class="capbar" data-level={capbar_level(pool["capacity_percent"])}>
+              <span style={"width: #{capbar_width(pool["capacity_percent"])}%"}></span>
+            </div>
+
+            <div class="sizes">
+              used {format_bytes(pool["allocated_bytes"] || 0)} ·
+              free {format_bytes(pool["free_bytes"] || 0)} ·
+              total {format_bytes(pool["size_bytes"] || 0)}
+              <span class="muted">({pool["capacity_percent"] || 0}%)</span>
+            </div>
+
             <div class="details">
-                cap {pool["capacity_percent"]}% ·
               frag {pool["fragmentation_percent"] || 0}% ·
               err {pool["error_count"] || 0} ·
-                vdevs {pool["vdev_count"] || 0} (deg {pool["degraded_vdev_count"] || 0})
+              vdevs {pool["vdev_count"] || 0} (deg {pool["degraded_vdev_count"] || 0}) ·
+              {pool_scrub_line(pool)}
             </div>
-            </div>
-            <div class="mono muted" style="font-size: 0.75rem; align-self: center; text-align: right;">
-              scrub<br/>{pool["last_scrub_end"] || "never"}
+
+            <div :for={v <- degraded_vdevs(pool)} class="callout err" style="margin-top: 0.4rem;">
+              {v["name"]} {v["state"]} · r={v["read_errors"]} w={v["write_errors"]} cksum={v["checksum_errors"]}
             </div>
           </div>
         </div>
@@ -155,6 +169,46 @@ defmodule ServerWeb.HostDetailLive do
   defp pool_badge_style("ONLINE"), do: "color: var(--ok);"
   defp pool_badge_style(_), do: "color: var(--crit);"
 
+  defp pool_layout(pool) do
+    case pool["pool_type"] do
+      nil -> "—"
+      "" -> "—"
+      t -> t
+    end
+  end
+
+  defp capbar_level(cap) when is_number(cap) and cap >= 90, do: "crit"
+  defp capbar_level(cap) when is_number(cap) and cap >= 80, do: "warn"
+  defp capbar_level(_), do: "ok"
+
+  defp capbar_width(cap) when is_number(cap), do: cap |> max(0) |> min(100)
+  defp capbar_width(_), do: 0
+
+  defp pool_scrub_line(%{"scan_state" => "SCANNING"} = pool) do
+    "#{scan_verb(pool)} scanning"
+  end
+
+  defp pool_scrub_line(%{"last_scrub_end" => end_time} = pool)
+       when is_binary(end_time) and end_time != "" do
+    prefix =
+      case pool["scan_state"] do
+        "FINISHED" -> "#{scan_verb(pool)} finished "
+        _ -> "#{scan_verb(pool)} "
+      end
+
+    prefix <> end_time
+  end
+
+  defp pool_scrub_line(_), do: "scrub never"
+
+  defp scan_verb(%{"scan_function" => "resilver"}), do: "resilver"
+  defp scan_verb(_), do: "scrub"
+
+  defp degraded_vdevs(pool) do
+    (pool["vdevs"] || [])
+    |> Enum.filter(fn v -> Map.get(v, "state") not in [nil, "ONLINE"] end)
+  end
+
   defp sys_line(nil), do: "—"
   defp sys_line(%{payload: p}) do
     get_in(p, ["system_info", "pve_version"]) || "—"

server/test/server_web/live/host_detail_live_test.exs

@@ -17,9 +17,42 @@ defmodule ServerWeb.HostDetailLiveTest do
           %{
             "name" => "rpool",
             "health" => "ONLINE",
+            "pool_type" => "mirror",
+            "size_bytes" => 500_000_000_000,
+            "allocated_bytes" => 200_000_000_000,
+            "free_bytes" => 300_000_000_000,
             "capacity_percent" => 40,
+            "fragmentation_percent" => 17,
             "error_count" => 0,
-            "last_scrub_end" => "Sat Apr 19 02:00:00 2026"
+            "vdev_count" => 1,
+            "degraded_vdev_count" => 0,
+            "scan_function" => "scrub",
+            "scan_state" => "FINISHED",
+            "last_scrub_end" => "Sat Apr 19 02:00:00 2026",
+            "vdevs" => [
+              %{"name" => "mirror-0", "type" => "mirror", "state" => "ONLINE",
+                "read_errors" => 0, "write_errors" => 0, "checksum_errors" => 0}
+            ]
+          },
+          %{
+            "name" => "tank",
+            "health" => "DEGRADED",
+            "pool_type" => "raidz2",
+            "size_bytes" => 8_000_000_000_000,
+            "allocated_bytes" => 6_000_000_000_000,
+            "free_bytes" => 2_000_000_000_000,
+            "capacity_percent" => 75,
+            "fragmentation_percent" => 55,
+            "error_count" => 2,
+            "vdev_count" => 1,
+            "degraded_vdev_count" => 1,
+            "scan_function" => "resilver",
+            "scan_state" => "SCANNING",
+            "last_scrub_end" => nil,
+            "vdevs" => [
+              %{"name" => "raidz2-0", "type" => "raidz2", "state" => "DEGRADED",
+                "read_errors" => 0, "write_errors" => 0, "checksum_errors" => 2}
+            ]
           }
         ]
       },
@@ -75,6 +108,19 @@ defmodule ServerWeb.HostDetailLiveTest do
     assert html =~ "nginx"
     assert html =~ "rpool/data"
     assert html =~ "local"
+    assert html =~ "mirror"
+    assert html =~ "465.7 GB"       # size_bytes formatted
+    assert html =~ "186.3 GB"       # allocated_bytes formatted
+    assert html =~ "279.4 GB"       # free_bytes formatted
+    assert html =~ "capbar"
+    assert html =~ "scrub finished Sat Apr 19 02:00:00 2026"
+    assert html =~ "tank"
+    assert html =~ "DEGRADED"
+    assert html =~ "raidz2"
+    assert html =~ "resilver scanning"
+    assert html =~ "raidz2-0 DEGRADED"
+    assert html =~ "cksum=2"
+    assert html =~ "callout err"
   end
 
   test "404 for unknown host", %{conn: conn} do