diff --git a/frontend/src/api/rulebooks.ts b/frontend/src/api/rulebooks.ts
index 01215e0..f884999 100644
--- a/frontend/src/api/rulebooks.ts
+++ b/frontend/src/api/rulebooks.ts
@@ -281,3 +281,59 @@ export async function includeAlwaysOnRulebook(projectId: number, rulebookId: num
   await apiDelete(`/api/projects/${projectId}/exclusions/rulebooks/${rulebookId}`);
 }
 
+
+/**
+ * One row of the staleness sweep. Unlike RuleHeader this carries the CHECK
+ * in full — the reader is about to go and run it, so the text is the point
+ * of the payload rather than the bloat a listing avoids.
+ */
+export interface RuleVerificationRow {
+  id: number;
+  title: string;
+  statement: string;
+  tier: RuleTier;
+  topic_id: number | null;
+  project_id: number | null;
+  when_to_apply: string;
+  verify_with: string;
+  expires_when: string;
+  /** A date (YYYY-MM-DD), or the literal "never". */
+  last_verified: string | null;
+  /** Null when never verified — "never" is not zero days ago. */
+  days_since_verified: number | null;
+}
+
+/**
+ * Rules asserting a fact that may have gone false, oldest verification
+ * first, never-checked at the top. Rules without a check never appear:
+ * they are decisions, and there is nothing to go and check.
+ *
+ * Not filterable by project — a project reaches rules through project
+ * scope, subscriptions, always-on rulebooks and exclusions, and a filter
+ * missing one of those paths would under-report.
+ */
+export async function listRulesDueForVerification(opts: {
+  olderThanDays?: number;
+  tier?: RuleTier;
+  neverOnly?: boolean;
+} = {}): Promise<{ rules: RuleVerificationRow[]; total: number }> {
+  const q = new URLSearchParams();
+  if (opts.olderThanDays) q.set("older_than_days", String(opts.olderThanDays));
+  if (opts.tier) q.set("tier", opts.tier);
+  if (opts.neverOnly) q.set("never_only", "true");
+  const qs = q.toString();
+  return apiGet(`/api/rules-due-for-verification${qs ? `?${qs}` : ""}`);
+}
+
+/**
+ * Record that a rule's check was RUN, and what it said.
+ *
+ * `stillTrue: false` writes nothing on purpose — a rule whose check failed
+ * is not in a recordable state, it is wrong — so it stays at the top of the
+ * sweep until someone corrects or retires it.
+ */
+export async function markRuleVerified(
+  id: number, stillTrue = true,
+): Promise<Rule & { verified: boolean }> {
+  return apiPost(`/api/rules/${id}/verify`, { still_true: stillTrue });
+}
diff --git a/src/scribe/mcp/tools/rulebooks.py b/src/scribe/mcp/tools/rulebooks.py
index 0e9fae8..43bd216 100644
--- a/src/scribe/mcp/tools/rulebooks.py
+++ b/src/scribe/mcp/tools/rulebooks.py
@@ -691,6 +691,97 @@ async def unrelate_rules(relation_id: int) -> dict:
         raise ValueError(f"relation {relation_id} not found")
     return {"deleted": relation_id}
 
+# ── The staleness sweep (milestone 312) ────────────────────────────────
+
+async def rules_due_for_verification(
+    older_than_days: int = 0, tier: str = "", never_only: bool = False,
+) -> dict:
+    """Which standing rules assert a FACT that nobody has confirmed lately.
+
+    A rulebook holds two kinds of thing. Most rules are DECISIONS — how the
+    operator wants to work. They have no truth value and cannot rot. A few
+    assert a fact about someone else's software: what a CI runner does, which
+    tools exist, what a setting is currently set to. Those go false silently,
+    with nobody present, and they keep being handed to every session as
+    binding instructions long after they stopped being true.
+
+    This lists the second kind, oldest verification first, never-checked at
+    the top. Each row carries the rule's `verify_with` in full — you are
+    about to go and run it — plus `expires_when`, and `days_since_verified`.
+
+    Reach for it when you are curating the rulebook, when a rule's advice
+    just contradicted what you observed, or periodically. Then, for each row:
+    run the check, and call mark_rule_verified with what you found.
+
+    Rules with no `verify_with` never appear here. That is correct: they are
+    decisions, and there is nothing to go and check. Do not "fix" their
+    absence by giving them checks — the list is only worth reading while
+    everything on it genuinely can go false.
+
+    Args:
+        older_than_days: only rules last verified longer ago than this.
+            Never-checked rules always qualify. 0 = no age filter.
+        tier: "always_on" or "conditional" to narrow. An always-on constraint
+            that has gone false is the expensive kind — it is preloaded into
+            every session, so a wrong one is wrong everywhere at once.
+        never_only: only rules nobody has ever verified.
+
+    NOT filterable by project, deliberately: a project reaches rules through
+    project scope, subscriptions, always-on rulebooks and exclusions, and a
+    filter that missed one of those paths would UNDER-report — which is the
+    exact failure this whole surface exists to prevent. Read the whole list.
+    """
+    uid = current_user_id()
+    rules = await rulebooks_svc.rules_due_for_verification(
+        uid, older_than_days=older_than_days, tier=tier, never_only=never_only,
+    )
+    return {
+        "rules": [rulebooks_svc.verification_row(r) for r in rules],
+        "total": len(rules),
+    }
+
+
+async def mark_rule_verified(rule_id: int, still_true: bool = True) -> dict:
+    """Record that you ran a rule's check — and what it said.
+
+    Call this AFTER actually running the rule's `verify_with`, never on the
+    strength of the rule sounding plausible. A stamp nobody earned is worse
+    than no stamp: it moves the rule to the bottom of the sweep and buys it
+    another long silence.
+
+    `still_true=False` writes NOTHING. A rule whose check failed is not in a
+    special state to be recorded — it is WRONG, and the only honest next
+    moves are to correct it, retire it, or find out why. So it stays at the
+    top of the sweep until someone deals with it, and the response tells you
+    what the rule said would end it.
+
+    Args:
+        rule_id: the rule whose check you ran.
+        still_true: True if the check passed. False if the fact it asserts is
+            no longer true — say so, that is the outcome worth having.
+    """
+    uid = current_user_id()
+    rule = await rulebooks_svc.mark_rule_verified(rule_id, uid, still_true)
+    if rule is None:
+        raise ValueError(
+            f"rule {rule_id} not found, or carries no verify_with "
+            f"(nothing to verify is not the same as verified)"
+        )
+    data = await rulebooks_svc.rule_detail(uid, rule)
+    if still_true:
+        data["verified"] = True
+        return data
+    data["verified"] = False
+    data["next"] = (
+        "This rule is no longer true and is still binding on every session "
+        "that loads it. Correct it with update_rule, retire it with "
+        "delete_rule, or open a task to work out what replaced it. Its "
+        "verified_at is deliberately untouched, so it stays at the top of "
+        "rules_due_for_verification until one of those happens."
+    )
+    return data
+
+
 def register(mcp) -> None:
     for fn in (
         list_rulebooks, get_rulebook, create_rulebook, update_rulebook, delete_rulebook,
@@ -702,5 +793,6 @@ def register(mcp) -> None:
         suppress_rule_for_project, unsuppress_rule_for_project,
         suppress_topic_for_project, unsuppress_topic_for_project,
         exclude_always_on_rulebook, include_always_on_rulebook,
+        rules_due_for_verification, mark_rule_verified,
     ):
         mcp.tool(name=fn.__name__)(fn)
diff --git a/src/scribe/routes/rulebooks.py b/src/scribe/routes/rulebooks.py
index e402584..2acc4bb 100644
--- a/src/scribe/routes/rulebooks.py
+++ b/src/scribe/routes/rulebooks.py
@@ -390,3 +390,56 @@ async def create_project_rule(project_id: int):
     return jsonify(await rulebooks_svc.rule_detail(
         get_current_user_id(), rule, data.get("system_ids"),
     )), 201
+
+
+# ── The staleness sweep (milestone 312) ────────────────────────────────
+
+@rulebooks_bp.get("/rules-due-for-verification")
+@login_required
+async def rules_due_for_verification():
+    """Rules that carry a check, oldest verification first, never-checked top.
+
+    Query params: older_than_days, tier, never_only. A rule with no
+    `verify_with` never appears — it is a decision, not a fact.
+    """
+    uid = get_current_user_id()
+    args = request.args
+    try:
+        older = int(args.get("older_than_days", 0) or 0)
+    except ValueError:
+        return jsonify({"error": "older_than_days must be an integer"}), 400
+    try:
+        rules = await rulebooks_svc.rules_due_for_verification(
+            uid,
+            older_than_days=older,
+            tier=args.get("tier", ""),
+            never_only=args.get("never_only", "").lower() in ("1", "true", "yes"),
+        )
+    except ValueError as exc:
+        # An unrecognised tier is a 400, not a silently narrowed result set:
+        # a filter that quietly answers a different question is the failure
+        # this whole surface exists to catch.
+        return jsonify({"error": str(exc)}), 400
+    return jsonify({
+        "rules": [rulebooks_svc.verification_row(r) for r in rules],
+        "total": len(rules),
+    })
+
+
+@rulebooks_bp.post("/rules/<int:rule_id>/verify")
+@login_required
+async def mark_rule_verified(rule_id: int):
+    """Record that the rule's check was run. Body: {"still_true": bool}.
+
+    `still_true: false` writes nothing — a rule whose check failed is wrong,
+    not in a recordable state — so it stays at the top of the sweep.
+    """
+    data = await request.get_json() or {}
+    uid = get_current_user_id()
+    still_true = data.get("still_true", True)
+    rule = await rulebooks_svc.mark_rule_verified(rule_id, uid, bool(still_true))
+    if rule is None:
+        return jsonify({"error": "rule not found, or carries no verify_with"}), 404
+    payload = await rulebooks_svc.rule_detail(uid, rule)
+    payload["verified"] = bool(still_true)
+    return jsonify(payload)
diff --git a/src/scribe/services/rulebooks.py b/src/scribe/services/rulebooks.py
index a6c1c8b..536754e 100644
--- a/src/scribe/services/rulebooks.py
+++ b/src/scribe/services/rulebooks.py
@@ -11,7 +11,7 @@ import logging
 from collections.abc import Iterable
 from typing import Optional
 
-from sqlalchemy import delete as sql_delete, insert, or_, select
+from sqlalchemy import and_, delete as sql_delete, insert, or_, select
 
 from scribe.models import async_session
 from scribe.models.system import System
@@ -1361,3 +1361,150 @@ def rules_payload(applicable: dict) -> dict:
         "suppressed_topics": applicable.get("suppressed_topics", []),
         "excluded_always_on": applicable.get("excluded_always_on", []),
     }
+
+
+# ── The staleness sweep (milestone 312) ────────────────────────────────
+
+async def rules_due_for_verification(
+    user_id: int,
+    older_than_days: int = 0,
+    tier: str = "",
+    never_only: bool = False,
+) -> list[Rule]:
+    """Rules that carry a check, oldest verification first, never-checked top.
+
+    THE QUERY THIS MILESTONE EXISTS FOR. `verify_with` and `expires_when` are
+    storage; this is what turns them into something that gets acted on. The
+    307 audit cost a session and found four broken rules by luck — this makes
+    the same question a list, and staleness measurable by age instead of
+    discoverable by accident.
+
+    Ordered `verified_at` ASC NULLS FIRST: never-checked outranks
+    checked-long-ago, because a rule nobody has ever confirmed is a claim
+    with no evidence behind it at all.
+
+    Rules with no `verify_with` never appear. That is not an omission — they
+    are decisions, there is nothing to go and check, and listing them would
+    dilute the result until nobody reads it.
+
+    Ownership-scoped exactly like list_rules: a rule reached through an owned
+    rulebook, or scoped to an owned project. Rules have no sharing ACL in this
+    schema — no rule_shares, no rulebook_shares — so there is no wider set to
+    consult here, unlike notes and projects.
+
+    Args:
+        user_id: whose rules.
+        older_than_days: only rules last verified longer ago than this.
+            Never-checked rules always qualify — they are the most overdue
+            thing there is. 0 = no age filter.
+        tier: "always_on" or "conditional" to narrow. Raises on anything else
+            rather than falling back: _valid_tier's silent always_on default
+            is right for a WRITE (the safe direction is to keep binding), and
+            wrong for a FILTER, where it would quietly answer a different
+            question than the one asked.
+        never_only: only rules that have never been verified.
+    """
+    from datetime import datetime, timedelta, timezone
+
+    from scribe.models.project import Project
+
+    if tier and tier not in TIERS:
+        raise ValueError(f"tier must be one of {TIERS}, got {tier!r}")
+
+    async with async_session() as session:
+        stmt = (
+            select(Rule)
+            .outerjoin(RulebookTopic, Rule.topic_id == RulebookTopic.id)
+            .outerjoin(Rulebook, RulebookTopic.rulebook_id == Rulebook.id)
+            .outerjoin(Project, Rule.project_id == Project.id)
+            .where(
+                Rule.deleted_at.is_(None),
+                Rule.verify_with.is_not(None),
+                # One statement rather than two queries merged in Python, so
+                # the ordering below is the database's and cannot disagree
+                # with itself across the two halves of the XOR.
+                or_(
+                    and_(
+                        Rulebook.owner_user_id == user_id,
+                        Rulebook.deleted_at.is_(None),
+                        RulebookTopic.deleted_at.is_(None),
+                    ),
+                    Project.user_id == user_id,
+                ),
+            )
+        )
+        if tier:
+            stmt = stmt.where(Rule.tier == tier)
+        if never_only:
+            stmt = stmt.where(Rule.verified_at.is_(None))
+        elif older_than_days > 0:
+            cutoff = datetime.now(timezone.utc) - timedelta(days=older_than_days)
+            stmt = stmt.where(
+                or_(Rule.verified_at.is_(None), Rule.verified_at < cutoff)
+            )
+        stmt = stmt.order_by(Rule.verified_at.asc().nullsfirst(), Rule.id)
+        return list((await session.execute(stmt)).scalars().all())
+
+
+def verification_row(rule: Rule) -> dict:
+    """One row of the sweep — the CHECK in full, unlike rule_brief.
+
+    The opposite call from a listing: here the caller is about to go and run
+    the check, so the text they need is the point of the payload rather than
+    the bloat. `days_since` is computed rather than left to the reader,
+    because "2026-06-14" and "74 days" prompt different reactions and only
+    one of them is the question being asked.
+    """
+    from datetime import datetime, timezone
+
+    days = None
+    if rule.verified_at is not None:
+        stamp = rule.verified_at
+        if stamp.tzinfo is None:
+            stamp = stamp.replace(tzinfo=timezone.utc)
+        days = (datetime.now(timezone.utc) - stamp).days
+    return {
+        "id": rule.id,
+        "title": rule.title,
+        "statement": rule.statement,
+        "tier": rule.tier,
+        "topic_id": rule.topic_id,
+        "project_id": rule.project_id,
+        "when_to_apply": rule.when_to_apply or "",
+        "verify_with": rule.verify_with or "",
+        "expires_when": rule.expires_when or "",
+        "last_verified": last_verified_label(rule),
+        "days_since_verified": days,
+    }
+
+
+async def mark_rule_verified(
+    rule_id: int, user_id: int, still_true: bool = True,
+) -> Optional[Rule]:
+    """Stamp a rule as verified — or, when the check FAILED, refuse to.
+
+    A failing check is the outcome worth having, and the asymmetry is
+    deliberate: passing writes a stamp, failing writes nothing. There is no
+    "verified false" state to record, because a rule whose check failed is
+    not a rule in a special condition — it is a rule that is WRONG, and the
+    only honest resolutions are to correct it, retire it, or find out why.
+    Recording the failure as a flag would let it sit there being false with
+    the sweep quietly satisfied that someone had looked.
+
+    So a failed check leaves `verified_at` untouched, and the rule stays at
+    the top of the sweep until someone actually deals with it.
+
+    Returns None when the rule is not found, not owned, or carries no
+    `verify_with` — nothing to verify is a different answer from verified.
+    """
+    from datetime import datetime, timezone
+
+    async with async_session() as session:
+        rule = await _fetch_owned_rule(session, rule_id, user_id)
+        if rule is None or not rule.verify_with:
+            return None
+        if still_true:
+            rule.verified_at = datetime.now(timezone.utc)
+            await session.commit()
+            await session.refresh(rule)
+        return rule
diff --git a/tests/test_integration_rule_verification.py b/tests/test_integration_rule_verification.py
index 381a245..8982153 100644
--- a/tests/test_integration_rule_verification.py
+++ b/tests/test_integration_rule_verification.py
@@ -134,3 +134,142 @@ async def test_editing_anything_else_leaves_the_stamp_alone(constraint):
     row = await _row(constraint["rule"])
     assert row.verified_at is not None
     assert row.why.startswith("act_runner picks the shell")
+
+
+# ── the sweep itself (step 3) ──────────────────────────────────────────
+
+@pytest_asyncio.fixture
+async def rulebook_of_three():
+    """A decision, a never-checked constraint, and a long-ago-checked one.
+
+    Three rows because the sweep's whole value is an ORDER, and an order
+    cannot be asserted with fewer.
+    """
+    async with async_session() as s:
+        owner = await ensure_user(s, "sweep_owner")
+        uid = owner.id
+        await s.commit()
+
+    book = await rulebooks_svc.create_rulebook(uid, "Sweep fixture")
+    topic = await rulebooks_svc.create_topic(book.id, uid, "mixed")
+    decision = await rulebooks_svc.create_rule(
+        topic.id, uid, "dev is home", "Work directly on dev.",
+    )
+    never = await rulebooks_svc.create_rule(
+        topic.id, uid, "The runner has no bash", "Use POSIX sh.",
+        verify_with="read the workflow's shell setting",
+    )
+    stale = await rulebooks_svc.create_rule(
+        topic.id, uid, "Bumps need a dashboard tick", "Tick it first.",
+        verify_with="cat CI-runner/renovate/config.js",
+        tier="conditional",
+    )
+    async with async_session() as s:
+        row = await s.get(Rule, stale.id)
+        row.verified_at = datetime(2026, 1, 1, tzinfo=timezone.utc)
+        await s.commit()
+    return {
+        "uid": uid, "decision": decision.id,
+        "never": never.id, "stale": stale.id,
+    }
+
+
+async def test_a_rule_with_no_check_is_never_in_the_sweep(rulebook_of_three):
+    """The common case, and the one that keeps the list worth reading.
+
+    Most rules are decisions. If they appeared here the sweep would be the
+    rulebook, and nobody would read it twice.
+    """
+    rules = await rulebooks_svc.rules_due_for_verification(rulebook_of_three["uid"])
+    assert rulebook_of_three["decision"] not in [r.id for r in rules]
+
+
+async def test_never_checked_outranks_checked_long_ago(rulebook_of_three):
+    """NULLS FIRST is the ordering decision this surface turns on.
+
+    Postgres sorts NULLs LAST by default on an ASC ordering, which would put
+    the rules nobody has ever confirmed at the BOTTOM — behind every rule
+    that at least once had someone look at it. That is exactly backwards: a
+    claim with no evidence at all outranks an old one.
+    """
+    ids = [r.id for r in await rulebooks_svc.rules_due_for_verification(
+        rulebook_of_three["uid"]
+    )]
+    assert ids.index(rulebook_of_three["never"]) < ids.index(rulebook_of_three["stale"])
+
+
+async def test_verifying_a_rule_moves_it_off_the_top(rulebook_of_three):
+    """The loop closing: check it, stamp it, and it stops being the question."""
+    await rulebooks_svc.mark_rule_verified(
+        rulebook_of_three["never"], rulebook_of_three["uid"], still_true=True,
+    )
+    ids = [r.id for r in await rulebooks_svc.rules_due_for_verification(
+        rulebook_of_three["uid"]
+    )]
+    # Still present — verified is not retired, and it will come due again.
+    assert rulebook_of_three["never"] in ids
+    assert ids.index(rulebook_of_three["stale"]) < ids.index(rulebook_of_three["never"])
+
+
+async def test_a_failed_check_writes_nothing(rulebook_of_three):
+    """The asymmetry that keeps the sweep honest.
+
+    There is no "verified false" state, because a rule whose check failed is
+    not in a special condition — it is WRONG. Recording the failure would let
+    it sit there being false with the sweep satisfied that someone looked.
+    """
+    before = await _row(rulebook_of_three["stale"])
+    await rulebooks_svc.mark_rule_verified(
+        rulebook_of_three["stale"], rulebook_of_three["uid"], still_true=False,
+    )
+    after = await _row(rulebook_of_three["stale"])
+    assert after.verified_at == before.verified_at
+
+
+async def test_a_rule_with_no_check_cannot_be_verified(rulebook_of_three):
+    """Nothing to verify is a different answer from verified — and stamping
+    one would put a decision into a sweep it has no business being in."""
+    assert await rulebooks_svc.mark_rule_verified(
+        rulebook_of_three["decision"], rulebook_of_three["uid"],
+    ) is None
+
+
+async def test_never_only_and_the_age_filter_narrow_to_what_they_say(rulebook_of_three):
+    uid = rulebook_of_three["uid"]
+    # Membership, not equality: the integration lane shares one database for
+    # the whole run and this fixture is function-scoped, so this owner has
+    # accumulated rules from earlier tests. Asserting the exact list would
+    # pass alone and fail in the suite.
+    never_ids = [r.id for r in await rulebooks_svc.rules_due_for_verification(
+        uid, never_only=True,
+    )]
+    assert rulebook_of_three["never"] in never_ids
+    assert rulebook_of_three["stale"] not in never_ids
+    assert rulebook_of_three["decision"] not in never_ids
+
+    # A rule checked in January is well past any sane window; one never
+    # checked always qualifies, because it is the most overdue thing there is.
+    aged = [r.id for r in await rulebooks_svc.rules_due_for_verification(
+        uid, older_than_days=30,
+    )]
+    assert rulebook_of_three["stale"] in aged
+    assert rulebook_of_three["never"] in aged
+
+
+async def test_the_tier_filter_narrows_to_one_tier(rulebook_of_three):
+    ids = [r.id for r in await rulebooks_svc.rules_due_for_verification(
+        rulebook_of_three["uid"], tier="conditional",
+    )]
+    assert rulebook_of_three["stale"] in ids
+    assert rulebook_of_three["never"] not in ids
+
+
+async def test_another_users_rules_are_not_in_your_sweep(rulebook_of_three):
+    """Rules are ownership-scoped: there is no rule-sharing ACL in this
+    schema, so the only correct answer is your own rules."""
+    async with async_session() as s:
+        stranger = await ensure_user(s, "sweep_stranger")
+        sid = stranger.id
+        await s.commit()
+
+    assert await rulebooks_svc.rules_due_for_verification(sid) == []
diff --git a/tests/test_mcp_tool_rulebooks.py b/tests/test_mcp_tool_rulebooks.py
index 1c68ffb..c922a06 100644
--- a/tests/test_mcp_tool_rulebooks.py
+++ b/tests/test_mcp_tool_rulebooks.py
@@ -217,13 +217,20 @@ async def test_unsubscribe_project_from_rulebook_calls_service():
     assert mock.called
 
 
-def test_register_attaches_all_sixteen_tools():
-    """register(mcp) should call mcp.tool(name=...) for all 16 tools."""
+def test_register_attaches_every_tool():
+    """Every tool in the module reaches the server.
+
+    The count is the guard: a function added to the module but left out of
+    register()'s tuple is invisible to callers and raises nothing. The name
+    said "sixteen" for ten tools' worth of growth — the number lives in the
+    assertion, not the title, so it cannot drift again.
+    """
     from scribe.mcp.tools.rulebooks import register
     mcp = FakeMCP()
 
     register(mcp)
-    assert len(mcp.names) == 26   # +relate_rules/unrelate_rules (milestone 307)
+    # 26 through milestone 307, +2 for the staleness sweep (milestone 312).
+    assert len(mcp.names) == 28
     # spot-check a few names
     assert "list_rulebooks" in mcp.names
     assert "create_rule" in mcp.names
@@ -234,6 +241,9 @@ def test_register_attaches_all_sixteen_tools():
     assert "include_always_on_rulebook" in mcp.names
     assert "create_project_rule" in mcp.names
     assert "suppress_rule_for_project" in mcp.names
+    # milestone 312: the sweep, and the stamp that answers it
+    assert "rules_due_for_verification" in mcp.names
+    assert "mark_rule_verified" in mcp.names
     assert "unsuppress_rule_for_project" in mcp.names
     assert "suppress_topic_for_project" in mcp.names
     assert "unsuppress_topic_for_project" in mcp.names
diff --git a/tests/test_services_rulebooks.py b/tests/test_services_rulebooks.py
index 69aba3b..eeaeb57 100644
--- a/tests/test_services_rulebooks.py
+++ b/tests/test_services_rulebooks.py
@@ -446,3 +446,62 @@ def test_the_check_text_itself_never_enters_a_listing():
     ))
     assert "verify_with" not in out
     assert "expires_when" not in out
+
+
+# ── the sweep's row shape (milestone 312 step 3) ────────────────────────
+
+def test_a_sweep_row_carries_the_check_in_full():
+    """The OPPOSITE call from rule_brief, and deliberately so.
+
+    A listing omits the depth because nobody reading it wants to act on one
+    rule. A sweep row exists to be acted on — the reader is about to go and
+    run the check — so the text is the payload's point, not its bloat.
+    """
+    from scribe.services.rulebooks import verification_row
+
+    row = verification_row(fake_rule(
+        verify_with="cat CI-runner/renovate/config.js",
+        expires_when="dependencyDashboardApproval is turned off",
+        when_to_apply="when a dependency bump is in play",
+    ))
+    assert row["verify_with"] == "cat CI-runner/renovate/config.js"
+    assert row["expires_when"] == "dependencyDashboardApproval is turned off"
+    assert row["when_to_apply"] == "when a dependency bump is in play"
+    assert row["tier"] == "always_on"
+
+
+def test_never_verified_reports_no_day_count_rather_than_zero():
+    """"Never" is not "0 days ago" — the second reads as freshly checked.
+
+    Getting this wrong would invert the row's meaning for exactly the rules
+    that most need attention.
+    """
+    from scribe.services.rulebooks import verification_row
+
+    row = verification_row(fake_rule(verify_with="read the workflow"))
+    assert row["last_verified"] == "never"
+    assert row["days_since_verified"] is None
+
+
+def test_a_verified_row_counts_the_days():
+    from datetime import timedelta
+
+    from scribe.services.rulebooks import verification_row
+
+    row = verification_row(fake_rule(
+        verify_with="read the workflow",
+        verified_at=datetime.now(timezone.utc) - timedelta(days=74, hours=1),
+    ))
+    assert row["days_since_verified"] == 74
+
+
+@pytest.mark.asyncio
+async def test_an_unrecognised_tier_filter_raises_rather_than_narrowing():
+    """_valid_tier's silent always_on fallback is right for a WRITE — a typo
+    should leave a rule binding. It is wrong for a FILTER, where the same
+    fallback would quietly answer a different question than the one asked and
+    return a short list that looks like good news."""
+    from scribe.services.rulebooks import rules_due_for_verification
+
+    with pytest.raises(ValueError, match="tier must be one of"):
+        await rules_due_for_verification(7, tier="occasionally")