diff --git a/config/config.exs b/config/config.exs
index 2e6f997..4ff1fc0 100644
--- a/config/config.exs
+++ b/config/config.exs
@@ -237,6 +237,7 @@ config :loopctl, Oban,
        {"0 2 * * *", Loopctl.Workers.CostRollupWorker},
        {"0 3 * * *", Loopctl.Workers.WebhookCleanupWorker},
        {"0 3 * * 0", Loopctl.Workers.TokenDataArchivalWorker},
+       {"0 4 * * *", Loopctl.Workers.KnowledgeLintWorker, args: %{"mode" => "all_tenants"}},
        {"*/5 * * * *", Loopctl.Workers.PendingEnrollmentCleanupWorker},
        {"* * * * *", Loopctl.Workers.ComputeSthWorker, args: %{"mode" => "all_tenants"}},
        {"* * * * *", Loopctl.Workers.RevokeExpiredDispatchesWorker}
diff --git a/lib/loopctl/workers/knowledge_lint_worker.ex b/lib/loopctl/workers/knowledge_lint_worker.ex
new file mode 100644
index 0000000..b029c5f
--- /dev/null
+++ b/lib/loopctl/workers/knowledge_lint_worker.ex
@@ -0,0 +1,136 @@
+defmodule Loopctl.Workers.KnowledgeLintWorker do
+  @moduledoc """
+  Oban worker that runs the knowledge-wiki lint nightly and acts on the findings.
+
+  This is the "nightly refinement" loop that both the Karpathy `llm-wiki`
+  pattern (lint-and-act) and the Dan Martell second-brain workflow converge on:
+  the lint *engine* already exists (`Loopctl.Knowledge.lint/2`); this worker is
+  the orchestration that RUNS it on a schedule and takes a safe, automated
+  repair action on the one finding that can be auto-repaired — orphans.
+
+  ## Scheduling
+
+  Configured via the Oban Cron plugin to run once nightly in `all_tenants`
+  mode, which fans out one per-tenant job per active tenant (mirroring
+  `Loopctl.Workers.ComputeSthWorker`). Lint is inherently per-tenant, so the
+  fan-out keeps each tenant's analysis in its own job (independent retries,
+  no cross-tenant coupling).
+
+  ## What it does per tenant
+
+  1. Runs `Knowledge.lint/2` (stale, orphan, contradiction, coverage-gap and
+     broken-source detection).
+  2. **Acts on orphans** — published articles with zero links. For each orphan
+     it re-enqueues `Loopctl.Workers.ArticleLinkingWorker`, which re-runs the
+     proven pgvector similarity pass against the *current* corpus. This is the
+     reason a nightly pass is valuable rather than a no-op: an article orphaned
+     in January (no neighbor cleared the similarity threshold at the time) can
+     find neighbors that were ingested months later. Re-linking is deterministic,
+     cheap, and makes **no** embedding-API calls (orphans missing an embedding
+     simply no-op in the linking worker — backfilling those is a separate
+     concern, out of scope here).
+  3. **Surfaces all findings** via an immutable audit event
+     (`knowledge.lint_completed`) carrying the full lint summary, so
+     contradictions / coverage gaps / broken sources / stale counts are
+     observable in the change feed even though they are not auto-repaired
+     (those require human judgment).
+
+  ## Scale safety
+
+  Lint caps each finding array at `max_per_category` (we request the ceiling,
+  500) while still reporting the *true* totals in `summary.total_per_category`.
+  Orphan re-link enqueues are additionally bounded by
+  `:knowledge_lint_max_orphan_relink` (default 500). When the true orphan count
+  exceeds what we act on, the gap is logged — never silently dropped — so an
+  operator can see that a backlog remains for the next run.
+  """
+
+  use Oban.Worker,
+    queue: :knowledge,
+    max_attempts: 3,
+    unique: [fields: [:worker, :args], period: 60]
+
+  require Logger
+
+  import Ecto.Query
+
+  alias Loopctl.AdminRepo
+  alias Loopctl.Audit
+  alias Loopctl.Knowledge
+  alias Loopctl.Tenants.Tenant
+  alias Loopctl.Workers.ArticleLinkingWorker
+
+  # Ask lint for the ceiling so we act on as many orphans per run as the engine
+  # will return; the true (pre-cap) totals still come back in the summary.
+  @lint_max_per_category 500
+  @default_max_orphan_relink 500
+
+  @impl Oban.Worker
+  def perform(%Oban.Job{args: %{"mode" => "all_tenants"}}) do
+    tenant_ids =
+      from(t in Tenant, where: t.status == :active, select: t.id)
+      |> AdminRepo.all()
+
+    for tenant_id <- tenant_ids do
+      %{"tenant_id" => tenant_id}
+      |> __MODULE__.new()
+      |> Oban.insert()
+    end
+
+    :ok
+  end
+
+  def perform(%Oban.Job{args: %{"tenant_id" => tenant_id}}) do
+    {:ok, report} = Knowledge.lint(tenant_id, max_per_category: @lint_max_per_category)
+
+    relinked = enqueue_orphan_relinks(tenant_id, report)
+    log_audit_event(tenant_id, report, relinked)
+
+    Logger.info(
+      "KnowledgeLintWorker: tenant=#{tenant_id} " <>
+        "issues=#{report.summary.total_issues} orphans_relinked=#{relinked}"
+    )
+
+    :ok
+  end
+
+  # --- Private ---
+
+  defp enqueue_orphan_relinks(tenant_id, report) do
+    max_relink =
+      Application.get_env(:loopctl, :knowledge_lint_max_orphan_relink, @default_max_orphan_relink)
+
+    orphans = Enum.take(report.orphan_articles, max_relink)
+    true_total = report.summary.total_per_category.orphan_articles
+
+    if true_total > length(orphans) do
+      Logger.warning(
+        "KnowledgeLintWorker: tenant=#{tenant_id} has #{true_total} orphan articles; " <>
+          "re-linking #{length(orphans)} this run (cap=#{max_relink}). Remainder retried next run."
+      )
+    end
+
+    Enum.each(orphans, fn %{article_id: article_id} ->
+      %{"article_id" => article_id, "tenant_id" => tenant_id}
+      |> ArticleLinkingWorker.new()
+      |> Oban.insert()
+    end)
+
+    length(orphans)
+  end
+
+  defp log_audit_event(tenant_id, report, relinked) do
+    Audit.create_log_entry(tenant_id, %{
+      entity_type: "knowledge_lint",
+      entity_id: tenant_id,
+      action: "knowledge.lint_completed",
+      actor_type: "system",
+      actor_id: nil,
+      actor_label: "worker:knowledge_lint",
+      new_state: %{
+        "summary" => report.summary,
+        "orphans_relinked" => relinked
+      }
+    })
+  end
+end
diff --git a/test/loopctl/workers/knowledge_lint_worker_test.exs b/test/loopctl/workers/knowledge_lint_worker_test.exs
new file mode 100644
index 0000000..75bcdf7
--- /dev/null
+++ b/test/loopctl/workers/knowledge_lint_worker_test.exs
@@ -0,0 +1,148 @@
+defmodule Loopctl.Workers.KnowledgeLintWorkerTest do
+  use Loopctl.DataCase, async: true
+  use Oban.Testing, repo: Loopctl.Repo
+
+  setup :verify_on_exit!
+
+  import Ecto.Query
+
+  alias Loopctl.AdminRepo
+  alias Loopctl.Audit.AuditLog
+  alias Loopctl.Knowledge.ArticleLink
+  alias Loopctl.Workers.KnowledgeLintWorker
+
+  # A published article with a known embedding vector, written directly via
+  # AdminRepo to bypass the inline Oban cascade (embedding -> linking) that
+  # `fixture(:article)` would otherwise trigger on publish.
+  defp published_article_with_embedding(tenant_id, embedding, attrs \\ %{}) do
+    base = %{
+      title: "Article #{System.unique_integer([:positive])}",
+      body: "Test article body.",
+      category: :pattern,
+      status: :draft,
+      tags: []
+    }
+
+    fixture(:article, Map.merge(base, Map.put(attrs, :tenant_id, tenant_id)))
+    |> Ecto.Changeset.change(%{status: :published, embedding: embedding})
+    |> AdminRepo.update!()
+  end
+
+  # Two near-identical directional vectors -> cosine similarity ~1.0, above the
+  # 0.6 linking threshold. (Cosine measures direction, not magnitude.)
+  defp similar_embedding, do: List.duplicate(1.0, 768) ++ List.duplicate(0.0, 768)
+
+  defp near_similar_embedding do
+    List.duplicate(1.0, 768)
+    |> List.update_at(0, fn _ -> 0.99 end)
+    |> List.update_at(1, fn _ -> 1.01 end)
+    |> Kernel.++(List.duplicate(0.01, 768))
+  end
+
+  defp lint_audit_entries(tenant_id) do
+    from(a in AuditLog,
+      where: a.tenant_id == ^tenant_id,
+      where: a.action == "knowledge.lint_completed"
+    )
+    |> AdminRepo.all()
+  end
+
+  describe "perform/1 per-tenant" do
+    test "logs a knowledge.lint_completed audit event carrying the lint summary" do
+      tenant = fixture(:tenant)
+      _article = published_article_with_embedding(tenant.id, similar_embedding())
+
+      assert :ok =
+               KnowledgeLintWorker.perform(%Oban.Job{args: %{"tenant_id" => tenant.id}})
+
+      assert [entry] = lint_audit_entries(tenant.id)
+      assert entry.actor_type == "system"
+      assert entry.actor_label == "worker:knowledge_lint"
+      # new_state is jsonb -> string keys on read
+      assert entry.new_state["summary"]["total_articles"] == 1
+      assert is_integer(entry.new_state["summary"]["total_issues"])
+      assert is_integer(entry.new_state["orphans_relinked"])
+    end
+
+    test "re-links orphan articles against the current corpus" do
+      tenant = fixture(:tenant)
+      # Two similar, published, unlinked articles -> both orphans.
+      a = published_article_with_embedding(tenant.id, similar_embedding())
+      b = published_article_with_embedding(tenant.id, near_similar_embedding())
+
+      assert :ok =
+               KnowledgeLintWorker.perform(%Oban.Job{args: %{"tenant_id" => tenant.id}})
+
+      # Orphan re-link (inline Oban) ran ArticleLinkingWorker -> a relates_to
+      # link now connects the previously-orphaned pair.
+      links =
+        from(l in ArticleLink,
+          where: l.tenant_id == ^tenant.id,
+          where: l.relationship_type == :relates_to,
+          where:
+            (l.source_article_id == ^a.id and l.target_article_id == ^b.id) or
+              (l.source_article_id == ^b.id and l.target_article_id == ^a.id)
+        )
+        |> AdminRepo.all()
+
+      assert length(links) == 1
+
+      assert [entry] = lint_audit_entries(tenant.id)
+      # Both were orphans at lint time, so both were enqueued for re-link.
+      assert entry.new_state["summary"]["total_per_category"]["orphan_articles"] == 2
+      assert entry.new_state["orphans_relinked"] == 2
+    end
+
+    test "handles a tenant with no published articles" do
+      tenant = fixture(:tenant)
+
+      assert :ok =
+               KnowledgeLintWorker.perform(%Oban.Job{args: %{"tenant_id" => tenant.id}})
+
+      assert [entry] = lint_audit_entries(tenant.id)
+      assert entry.new_state["summary"]["total_articles"] == 0
+      assert entry.new_state["orphans_relinked"] == 0
+    end
+  end
+
+  describe "perform/1 all_tenants mode" do
+    test "fans out and lints every active tenant, skipping inactive ones" do
+      active_a = fixture(:tenant)
+      active_b = fixture(:tenant)
+      suspended = fixture(:tenant, %{status: :suspended})
+
+      for t <- [active_a, active_b, suspended] do
+        published_article_with_embedding(t.id, similar_embedding())
+      end
+
+      assert :ok =
+               KnowledgeLintWorker.perform(%Oban.Job{args: %{"mode" => "all_tenants"}})
+
+      assert [_] = lint_audit_entries(active_a.id)
+      assert [_] = lint_audit_entries(active_b.id)
+      assert [] == lint_audit_entries(suspended.id)
+    end
+  end
+
+  describe "tenant isolation" do
+    test "lint summary counts only the caller tenant's articles" do
+      tenant_a = fixture(:tenant)
+      tenant_b = fixture(:tenant)
+
+      published_article_with_embedding(tenant_a.id, similar_embedding())
+      published_article_with_embedding(tenant_a.id, near_similar_embedding())
+
+      published_article_with_embedding(tenant_b.id, similar_embedding())
+      published_article_with_embedding(tenant_b.id, near_similar_embedding())
+      published_article_with_embedding(tenant_b.id, similar_embedding())
+
+      assert :ok =
+               KnowledgeLintWorker.perform(%Oban.Job{args: %{"tenant_id" => tenant_a.id}})
+
+      assert [entry] = lint_audit_entries(tenant_a.id)
+      assert entry.new_state["summary"]["total_articles"] == 2
+      # Tenant B was never linted.
+      assert [] == lint_audit_entries(tenant_b.id)
+    end
+  end
+end