diff --git a/frontend/src/api/rulebooks.ts b/frontend/src/api/rulebooks.ts
index 2c3eb8c..01215e0 100644
--- a/frontend/src/api/rulebooks.ts
+++ b/frontend/src/api/rulebooks.ts
@@ -55,6 +55,16 @@ export interface Rule {
   tier: RuleTier;
   why: string;
   how_to_apply: string;
+  /**
+   * How to check the rule is still true, and the state that ends it. Set
+   * only on a rule that asserts a fact about something outside the
+   * operator's control; empty on a rule that is a decision, which is most
+   * of them. Empty is meaningful, not missing.
+   */
+  verify_with: string;
+  expires_when: string;
+  /** When the check last passed. Null means never checked. */
+  verified_at: string | null;
   /** The note or task that caused this rule, if one was recorded. */
   arose_from_id: number | null;
   order_index: number;
@@ -80,6 +90,12 @@ export interface RuleHeader {
   updated_at: string | null;
   when_to_apply?: string;
   arose_from_id?: number;
+  /**
+   * Present ONLY on a rule that carries a check — the presence of the key
+   * is itself the signal that this rule asserts a fact that can go false.
+   * A date (YYYY-MM-DD), or the literal "never".
+   */
+  last_verified?: string;
 }
 
 export interface ApplicableRules {
@@ -170,7 +186,14 @@ export async function getRule(id: number): Promise<Rule> {
   return apiGet(`/api/rules/${id}`);
 }
 
-/** The fields both write paths accept. `system_ids` REPLACES a rule's areas. */
+/**
+ * The fields both write paths accept. `system_ids` REPLACES a rule's areas.
+ *
+ * Sending "" for a nullable text field CLEARS it here — the server maps an
+ * empty string to NULL, so an emptied form input does what it looks like it
+ * does. (The MCP door reads "" as "leave unchanged" and needs an explicit
+ * clear_fields list instead; the two idioms reach the same state.)
+ */
 export interface RuleWrite {
   title: string;
   statement: string;
@@ -181,6 +204,8 @@ export interface RuleWrite {
   order_index: number;
   system_ids: number[];
   arose_from_id: number | null;
+  verify_with: string;
+  expires_when: string;
 }
 
 export async function createRule(topicId: number, data: Partial<RuleWrite> & { title: string; statement: string }): Promise<Rule> {
diff --git a/src/scribe/mcp/tools/rulebooks.py b/src/scribe/mcp/tools/rulebooks.py
index 6d3c094..0e9fae8 100644
--- a/src/scribe/mcp/tools/rulebooks.py
+++ b/src/scribe/mcp/tools/rulebooks.py
@@ -246,6 +246,14 @@ async def list_always_on_rules(project_id: int = 0) -> dict:
     Pair with get_project(id).applicable_rules when working on a specific
     project to also load that project's subscription-derived rules.
 
+    A rule carrying `last_verified` asserts a FACT about something outside the
+    operator's control — a runner's shell, a tool's existence, a setting
+    somewhere. It is still binding; the field says how long ago anyone
+    confirmed it, and "never" means nobody has. Follow the rule, and if you
+    are already standing where the check could be made, make it: get_rule
+    gives you its `verify_with`. Most rules have no such field, which means
+    they are decisions and there is nothing to check.
+
     Args:
         project_id: 0 (default) = the user-wide set. Inside a project, pass
             its id: an always-on rulebook the project EXCLUDED at inception
@@ -276,7 +284,8 @@ async def create_rule(
     topic_id: int, title: str, statement: str, when_to_apply: str = "",
     why: str = "", how_to_apply: str = "", order_index: int = 0,
     tier: str = "always_on", system_ids: list[int] | None = None,
-    arose_from_id: int = 0, force: bool = False,
+    arose_from_id: int = 0, verify_with: str = "", expires_when: str = "",
+    force: bool = False,
 ) -> dict:
     """Create a new rule in a rulebook (a SHARED rule — keep it general).
 
@@ -314,6 +323,15 @@ async def create_rule(
             optional: it decides the tier below, it is how the rule is found
             when it matters, and a rule nobody can place is a rule nobody
             applies.
+            This field is also the rule's RETRIEVAL SURFACE — it and the
+            statement are what a search is matched against, so it should
+            carry the SYMPTOM, not just the situation: the words someone
+            would actually type while stuck. Measured (note 3078): a rule
+            whose trigger named only its situation did not surface at all
+            for the problem it solves; adding the symptom to the same field
+            brought it back as the top hit. Where a rule prevents a specific
+            failure, put that failure's vocabulary here — the error text,
+            the wrong behaviour, the dead end.
         tier: "always_on" (default) or "conditional".
             The test: can you name the trigger WITHOUT naming a system, an
             artifact type or a moment? If the honest answer is "whenever you
@@ -328,6 +346,23 @@ async def create_rule(
             cannot be followed and does not survive a rewording.
         why: Optional rationale — the reason the rule exists.
         how_to_apply: Optional operationalization — when / where it kicks in.
+        verify_with: How to CHECK this rule is still true. Set it only when
+            the rule asserts a fact about something outside your control — a
+            runner's shell, a bot's config, whether a tool exists. Those go
+            false silently, with nobody present. Give a command, a path, a
+            URL or a query; something runnable beats prose, because prose
+            has to be re-interpreted by whoever finds it.
+            LEAVE IT EMPTY for a rule that is a DECISION — a preference, a
+            standard, a way of working. A decision has no truth value: it
+            changes when you change it, and you know that you did. An empty
+            verify_with is not a gap, it is the marker for "there is nothing
+            to go and check," and the whole signal is worthless the moment
+            it is filled in out of tidiness.
+        expires_when: The STATE under which this rule stops being true —
+            "when the runner can be given a bash shell", "when the dashboard
+            approval setting is turned off". Deliberately not a date: a
+            constraint expires when the ground under it moves, not on a
+            schedule. Pairs with verify_with; both empty is the normal case.
         order_index: Display order within the topic (default 0).
         force: Bypass the near-duplicate gate. By default, a title-identical rule
             already in this topic BLOCKS creation and returns its id so you update
@@ -343,6 +378,7 @@ async def create_rule(
         title=title, statement=statement, when_to_apply=when_to_apply,
         tier=tier, arose_from_id=arose_from_id,
         why=why, how_to_apply=how_to_apply, order_index=order_index,
+        verify_with=verify_with, expires_when=expires_when,
     )
     return await rulebooks_svc.rule_detail(uid, rule, system_ids)
 
@@ -351,7 +387,8 @@ async def create_project_rule(
     project_id: int, statement: str, title: str = "", when_to_apply: str = "",
     why: str = "", how_to_apply: str = "", order_index: int = 0,
     tier: str = "always_on", system_ids: list[int] | None = None,
-    arose_from_id: int = 0, force: bool = False,
+    arose_from_id: int = 0, verify_with: str = "", expires_when: str = "",
+    force: bool = False,
 ) -> dict:
     """Create a rule scoped to a single project (no rulebook needed).
 
@@ -383,6 +420,13 @@ async def create_project_rule(
         arose_from_id: The note or task that CAUSED this rule.
         why: Optional rationale — the reason the rule exists.
         how_to_apply: Optional operationalization — when / where it kicks in.
+        verify_with: How to check this rule is still true — see create_rule.
+            Set it when the rule asserts a fact about someone else's software;
+            leave it empty when the rule is a decision. Project rules are the
+            likelier home for a real check: they name this project's files,
+            paths and quirks, which is exactly the kind of claim that rots.
+        expires_when: The state under which the rule stops being true — see
+            create_rule. A state, not a date.
         order_index: Display order within the project's rule list (default 0).
         force: Bypass the near-duplicate gate. By default, a title-identical rule
             already on this project BLOCKS creation and returns its id so you
@@ -399,6 +443,7 @@ async def create_project_rule(
         title=derived_title, statement=statement, when_to_apply=when_to_apply,
         tier=tier, arose_from_id=arose_from_id,
         why=why, how_to_apply=how_to_apply, order_index=order_index,
+        verify_with=verify_with, expires_when=expires_when,
     )
     return await rulebooks_svc.rule_detail(uid, rule, system_ids)
 
@@ -407,12 +452,33 @@ async def update_rule(
     rule_id: int, title: str = "", statement: str = "", when_to_apply: str = "",
     why: str = "", how_to_apply: str = "", order_index: int = -1,
     tier: str = "", system_ids: list[int] | None = None, arose_from_id: int = 0,
+    verify_with: str = "", expires_when: str = "",
+    clear_fields: list[str] | None = None,
 ) -> dict:
     """Update a rule. Empty strings / order_index=-1 leave fields unchanged.
 
     Adding `when_to_apply` and a `tier` to an existing rule is the ordinary way
     a rule stops being preloaded into every session and starts arriving when it
     is relevant. `system_ids` REPLACES the rule's areas (pass [] to clear).
+
+    TO EMPTY A FIELD, NAME IT: clear_fields=["verify_with"]. Passing "" cannot
+    do it — "" means "leave this alone" here, which is what lets you update
+    two fields without wiping the other six. Clearable: why, how_to_apply,
+    when_to_apply, verify_with, expires_when, arose_from_id. Clearing and
+    setting the same field in one call clears it first, so the new value wins.
+
+    Editing `verify_with` DROPS the rule's verification stamp. The stamp
+    certifies a check, not a rule; once the check is reworded the old stamp
+    vouches for something that no longer exists, so the rule re-enters the
+    staleness sweep as never-verified.
+
+    Args:
+        verify_with: How to check the rule is still true — set it when the
+            rule asserts a fact about someone else's software, leave it empty
+            when the rule is a decision. See create_rule.
+        expires_when: The state under which the rule stops being true. A
+            state, not a date. See create_rule.
+        clear_fields: Names of fields to empty, as above.
     """
     uid = current_user_id()
     fields: dict = {}
@@ -430,9 +496,15 @@ async def update_rule(
         fields["why"] = why
     if how_to_apply:
         fields["how_to_apply"] = how_to_apply
+    if verify_with:
+        fields["verify_with"] = verify_with
+    if expires_when:
+        fields["expires_when"] = expires_when
     if order_index >= 0:
         fields["order_index"] = order_index
-    rule = await rulebooks_svc.update_rule(rule_id, uid, **fields)
+    rule = await rulebooks_svc.update_rule(
+        rule_id, uid, clear=clear_fields or (), **fields,
+    )
     if rule is None:
         raise ValueError(f"rule {rule_id} not found")
     return await rulebooks_svc.rule_detail(uid, rule, system_ids)
diff --git a/src/scribe/mcp/tools/search.py b/src/scribe/mcp/tools/search.py
index e7eb1c4..c6db75d 100644
--- a/src/scribe/mcp/tools/search.py
+++ b/src/scribe/mcp/tools/search.py
@@ -14,6 +14,7 @@ from scribe.services.access import owner_names_for
 from scribe.services.embeddings import (
     DEFAULT_SIMILARITY_THRESHOLD, semantic_search_notes, semantic_search_rules,
 )
+from scribe.services import rulebooks as rulebooks_svc
 from scribe.services.retrieval_telemetry import record_retrieval, retrieval_summary
 
 
@@ -23,7 +24,10 @@ async def _search_rules(uid: int, q: str, limit: int) -> dict:
     A rule hit carries `why` and `how_to_apply`: they are the operational half
     of a rule and the session-start payload never includes them, so a caller
     who went looking should get the whole thing rather than a summary they then
-    have to re-fetch.
+    have to re-fetch. It also carries the rule's check (`verify_with`,
+    `expires_when`, `last_verified`) when it has one — a search hit is exactly
+    the moment someone is about to act on a rule, and "this asserts a fact
+    nobody has confirmed" is part of what the rule says.
 
     Rules are not project-scoped the way notes are (a family rule belongs to no
     project), so `project_id` and `system_id` do not apply here.
@@ -39,6 +43,14 @@ async def _search_rules(uid: int, q: str, limit: int) -> dict:
                 "tier": rule.tier,
                 "why": rule.why or "",
                 "how_to_apply": rule.how_to_apply or "",
+                "verify_with": rule.verify_with or "",
+                "expires_when": rule.expires_when or "",
+                # Only on a rule that carries a check; its absence means the
+                # rule is a decision, not that nobody has looked.
+                **(
+                    {"last_verified": rulebooks_svc.last_verified_label(rule)}
+                    if rule.verify_with else {}
+                ),
                 "topic_id": rule.topic_id,
                 "project_id": rule.project_id,
                 "similarity": float(score),
diff --git a/src/scribe/routes/rulebooks.py b/src/scribe/routes/rulebooks.py
index 08d0d9e..e402584 100644
--- a/src/scribe/routes/rulebooks.py
+++ b/src/scribe/routes/rulebooks.py
@@ -165,6 +165,8 @@ async def create_rule(topic_id: int):
             when_to_apply=data.get("when_to_apply", ""),
             tier=data.get("tier", "always_on"),
             arose_from_id=data.get("arose_from_id", 0) or 0,
+            verify_with=data.get("verify_with", ""),
+            expires_when=data.get("expires_when", ""),
         )
     except ValueError as exc:
         return jsonify({"error": str(exc)}), 404
@@ -191,8 +193,13 @@ async def update_rule(rule_id: int):
     fields = {
         k: v for k, v in data.items()
         if k in ("title", "statement", "why", "how_to_apply", "order_index",
-                 "when_to_apply", "tier", "arose_from_id")
+                 "when_to_apply", "tier", "arose_from_id",
+                 "verify_with", "expires_when")
     }
+    # No clear_fields here: a form sends "" for an emptied input, and the
+    # service normalises "" to NULL for every nullable text column. The MCP
+    # door needs the explicit list only because "" already means "unchanged"
+    # there — two idioms, one outcome.
     rule = await rulebooks_svc.update_rule(rule_id, uid, **fields)
     if rule is None:
         return jsonify({"error": "rule not found"}), 404
@@ -375,6 +382,8 @@ async def create_project_rule(project_id: int):
             when_to_apply=data.get("when_to_apply", ""),
             tier=data.get("tier", "always_on"),
             arose_from_id=data.get("arose_from_id", 0) or 0,
+            verify_with=data.get("verify_with", ""),
+            expires_when=data.get("expires_when", ""),
         )
     except ValueError as exc:
         return jsonify({"error": str(exc)}), 404
diff --git a/src/scribe/services/rulebooks.py b/src/scribe/services/rulebooks.py
index aece902..a6c1c8b 100644
--- a/src/scribe/services/rulebooks.py
+++ b/src/scribe/services/rulebooks.py
@@ -8,6 +8,7 @@ depending on the caller's needs (mirroring services/events.py pattern).
 from __future__ import annotations
 
 import logging
+from collections.abc import Iterable
 from typing import Optional
 
 from sqlalchemy import delete as sql_delete, insert, or_, select
@@ -288,6 +289,17 @@ TIERS = ("always_on", "conditional")
 RELATION_KINDS = ("co_surfaces", "overrides", "elaborates")
 
 
+# The rule columns that are nullable, and therefore the ones where EMPTY has
+# to mean empty. A write that stores "" leaves a column that is not NULL and
+# not content — `verify_with IS NOT NULL` would then be true for a rule with
+# no check, and the staleness sweep would list rules it should never see.
+# Normalising here, at the one service seam, is what makes "unset" a single
+# state instead of two that read alike through to_dict's `or ""`.
+NULLABLE_RULE_TEXT = (
+    "why", "how_to_apply", "when_to_apply", "verify_with", "expires_when",
+)
+
+
 def _valid_tier(tier: str) -> str:
     """An unrecognised tier falls back to always_on — the SAFE direction.
 
@@ -299,6 +311,21 @@ def _valid_tier(tier: str) -> str:
     return tier if tier in TIERS else "always_on"
 
 
+def last_verified_label(rule: Rule) -> str | None:
+    """How long ago the rule's check passed — None when it carries no check.
+
+    One helper because two surfaces need the same answer and the brief-dict
+    lesson in rule_brief's docstring is what happens otherwise: three copies
+    that had already drifted. `None` means "this rule is a decision, the
+    question does not apply"; "never" means "it is a fact and nobody has
+    confirmed it" — a distinction worth keeping, because the second is the
+    one worth acting on.
+    """
+    if not rule.verify_with:
+        return None
+    return rule.verified_at.date().isoformat() if rule.verified_at else "never"
+
+
 def rule_brief(rule: Rule, **extra) -> dict:
     """The shape a rule takes when it is SURFACED rather than opened.
 
@@ -331,6 +358,16 @@ def rule_brief(rule: Rule, **extra) -> dict:
         out["when_to_apply"] = rule.when_to_apply
     if rule.arose_from_id:
         out["arose_from_id"] = rule.arose_from_id
+    # Present ONLY on a rule that carries a check — its presence is the
+    # signal, and it says two things at once: this rule asserts a fact that
+    # can go false, and here is how long ago anyone confirmed it. The check
+    # text itself stays in get_rule; a listing needs to know WHICH rules can
+    # rot, not how to test them. "never" rather than null, per #2483: a key
+    # that reads as an unused capability is a different claim from a rule
+    # nobody has ever verified.
+    stamp = last_verified_label(rule)
+    if stamp:
+        out["last_verified"] = stamp
     out.update({k: v for k, v in extra.items() if v is not None})
     return out
 
@@ -436,6 +473,7 @@ async def create_rule(
     topic_id: int, user_id: int, title: str, statement: str,
     why: str = "", how_to_apply: str = "", order_index: int = 0,
     when_to_apply: str = "", tier: str = "always_on", arose_from_id: int = 0,
+    verify_with: str = "", expires_when: str = "",
 ) -> Rule:
     async with async_session() as session:
         await _assert_topic_owned(session, topic_id, user_id)
@@ -447,6 +485,8 @@ async def create_rule(
             tier=_valid_tier(tier),
             why=why or None,
             how_to_apply=how_to_apply or None,
+            verify_with=verify_with or None,
+            expires_when=expires_when or None,
             arose_from_id=arose_from_id or None,
             order_index=order_index,
         )
@@ -461,6 +501,7 @@ async def create_project_rule(
     project_id: int, user_id: int, title: str, statement: str,
     why: str = "", how_to_apply: str = "", order_index: int = 0,
     when_to_apply: str = "", tier: str = "always_on", arose_from_id: int = 0,
+    verify_with: str = "", expires_when: str = "",
 ) -> Rule:
     """Create a rule scoped to a single project (no rulebook ceremony).
 
@@ -478,6 +519,8 @@ async def create_project_rule(
             tier=_valid_tier(tier),
             why=why or None,
             how_to_apply=how_to_apply or None,
+            verify_with=verify_with or None,
+            expires_when=expires_when or None,
             arose_from_id=arose_from_id or None,
             order_index=order_index,
         )
@@ -681,7 +724,23 @@ async def get_rule(rule_id: int, user_id: int) -> Optional[Rule]:
         return await _fetch_owned_rule(session, rule_id, user_id)
 
 
-async def update_rule(rule_id: int, user_id: int, **fields) -> Optional[Rule]:
+async def update_rule(
+    rule_id: int, user_id: int, clear: Iterable[str] = (), **fields,
+) -> Optional[Rule]:
+    """Patch a rule. `clear` names fields to unset; **fields carries new values.
+
+    Clearing is EXPLICIT and separate because a nullable field cannot be
+    emptied by passing it. The MCP door reads "" as "leave this alone" — an
+    agent filling three fields must not wipe the other five — so a caller
+    there has no value that means "remove it", and a rule that stops being a
+    constraint genuinely needs its check removed. Naming the field is the one
+    form that cannot happen by accident.
+
+    Callers that DO have a meaningful empty value (the REST door, where a
+    cleared form input arrives as "") get the same outcome through
+    NULLABLE_RULE_TEXT normalisation below, so the two doors keep their own
+    idiom and agree about the result.
+    """
     async with async_session() as session:
         rule = await _fetch_owned_rule(session, rule_id, user_id)
         if rule is None:
@@ -689,10 +748,32 @@ async def update_rule(rule_id: int, user_id: int, **fields) -> Optional[Rule]:
         allowed = {
             "title", "statement", "why", "how_to_apply", "order_index",
             "when_to_apply", "tier", "arose_from_id",
+            "verify_with", "expires_when",
         }
+        check_before = rule.verify_with
+        for key in clear:
+            if key in allowed and key in NULLABLE_RULE_TEXT:
+                setattr(rule, key, None)
+            elif key == "arose_from_id":
+                setattr(rule, key, None)
         for key, value in fields.items():
-            if key in allowed and value is not None:
-                setattr(rule, key, _valid_tier(value) if key == "tier" else value)
+            if key not in allowed or value is None:
+                continue
+            if key == "tier":
+                value = _valid_tier(value)
+            elif key in NULLABLE_RULE_TEXT:
+                value = value or None
+            elif key == "arose_from_id":
+                value = value or None
+            setattr(rule, key, value)
+        # A verification stamp certifies A CHECK, not a rule. Rewrite or
+        # remove the check and the old stamp certifies something that no
+        # longer exists — so it is dropped, and the rule re-enters the sweep.
+        # The safe direction, for the same reason _valid_tier falls back to
+        # always_on: a rule wrongly listed as due costs one look, a rule
+        # wrongly vouched for costs the thing the sweep exists to catch.
+        if rule.verify_with != check_before:
+            rule.verified_at = None
         await session.commit()
         await session.refresh(rule)
         _refresh_rule_embedding(rule)
diff --git a/tests/helpers.py b/tests/helpers.py
index e263e61..df77475 100644
--- a/tests/helpers.py
+++ b/tests/helpers.py
@@ -159,6 +159,11 @@ def fake_rule(**attrs) -> MagicMock:
         # `when_to_apply` and `arose_from_id` would be truthy MagicMocks and
         # rule_brief would attach both keys on every stand-in.
         "when_to_apply": None, "tier": "always_on", "arose_from_id": None,
+        # Same reason, and the same trap one field further on: an unnamed
+        # `verify_with` is a truthy MagicMock, so every stand-in rule would
+        # claim to carry a check and rule_brief would stamp a MagicMock date
+        # onto all of them. Most rules have none — that is the default here.
+        "verify_with": None, "expires_when": None, "verified_at": None,
         "order_index": 0, "created_at": _now(), "updated_at": _now(),
     }, attrs)
 
diff --git a/tests/test_integration_rule_verification.py b/tests/test_integration_rule_verification.py
new file mode 100644
index 0000000..381a245
--- /dev/null
+++ b/tests/test_integration_rule_verification.py
@@ -0,0 +1,136 @@
+"""Real-Postgres tests for a rule's CHECK — the write half (milestone 312).
+
+What mocks cannot prove, and what the staleness sweep depends on:
+
+1. **Empty means NULL.** The sweep asks for rules where `verify_with` is set.
+   A write that stored "" would leave a column that is neither null nor
+   content, and every rule ever touched through the REST door would answer
+   "yes, I have a check" — the sweep would list the whole rulebook and mean
+   nothing. Only a real column can show the difference; `to_dict`'s `or ""`
+   renders both the same.
+
+2. **Clearing is possible at all.** "" means "leave unchanged" at the MCP
+   door, so without an explicit clear there is no way to retire a check.
+
+3. **A stamp does not outlive the check it certifies.** Reword the check and
+   the old `verified_at` vouches for something that no longer exists.
+"""
+from datetime import datetime, timezone
+
+import pytest
+import pytest_asyncio
+
+from scribe.models import async_session
+from scribe.models.rulebook import Rule
+from scribe.services import rulebooks as rulebooks_svc
+from tests.helpers import ensure_user
+
+pytestmark = [pytest.mark.integration, pytest.mark.usefixtures("_dispose_engine")]
+
+
+@pytest_asyncio.fixture
+async def constraint():
+    """One rule carrying a check, already verified.
+
+    Verified at creation time rather than left null, because every assertion
+    here is about what happens to an EXISTING stamp — a fixture that started
+    null could pass all of them by doing nothing.
+    """
+    async with async_session() as s:
+        owner = await ensure_user(s, "verification_owner")
+        uid = owner.id
+        await s.commit()
+
+    book = await rulebooks_svc.create_rulebook(uid, "Environment facts")
+    topic = await rulebooks_svc.create_topic(book.id, uid, "ci")
+    rule = await rulebooks_svc.create_rule(
+        topic.id, uid, "The runner has no bash",
+        "Write every `run:` step in POSIX sh.",
+        verify_with="read the workflow's shell setting",
+        expires_when="the runner can be given a bash shell",
+    )
+    async with async_session() as s:
+        row = await s.get(Rule, rule.id)
+        row.verified_at = datetime(2026, 8, 1, tzinfo=timezone.utc)
+        await s.commit()
+    return {"uid": uid, "rule": rule.id}
+
+
+async def _row(rule_id: int) -> Rule:
+    async with async_session() as s:
+        return await s.get(Rule, rule_id)
+
+
+async def test_the_check_and_its_expiry_persist(constraint):
+    row = await _row(constraint["rule"])
+    assert row.verify_with == "read the workflow's shell setting"
+    assert row.expires_when == "the runner can be given a bash shell"
+    assert row.verified_at is not None
+
+
+async def test_an_empty_string_becomes_null_not_an_empty_column(constraint):
+    """The REST door's idiom: a cleared form input arrives as "".
+
+    NULL is asserted directly against the column rather than through to_dict,
+    which renders `None` and `""` identically — the difference this test
+    exists for would be invisible one layer up.
+    """
+    await rulebooks_svc.update_rule(
+        constraint["rule"], constraint["uid"], verify_with="", expires_when="",
+    )
+    row = await _row(constraint["rule"])
+    assert row.verify_with is None
+    assert row.expires_when is None
+
+
+async def test_naming_a_field_in_clear_empties_it(constraint):
+    """The MCP door's idiom, where "" already means "leave this alone"."""
+    await rulebooks_svc.update_rule(
+        constraint["rule"], constraint["uid"], clear=["verify_with"],
+    )
+    row = await _row(constraint["rule"])
+    assert row.verify_with is None
+    # expires_when was NOT named, so it survives — clearing is per-field, and
+    # a caller retiring one field must not lose the others.
+    assert row.expires_when == "the runner can be given a bash shell"
+
+
+async def test_rewording_the_check_drops_the_stamp(constraint):
+    """A stamp certifies a check, not a rule.
+
+    The safe direction, for the same reason _valid_tier falls back to
+    always_on: a rule wrongly listed as due costs one look, a rule wrongly
+    vouched for costs exactly what the sweep exists to catch.
+    """
+    await rulebooks_svc.update_rule(
+        constraint["rule"], constraint["uid"],
+        verify_with="read the runner's container shell, not the image's",
+    )
+    row = await _row(constraint["rule"])
+    assert row.verified_at is None
+
+
+async def test_clearing_the_check_drops_the_stamp(constraint):
+    await rulebooks_svc.update_rule(
+        constraint["rule"], constraint["uid"], clear=["verify_with"],
+    )
+    row = await _row(constraint["rule"])
+    assert row.verified_at is None
+
+
+async def test_editing_anything_else_leaves_the_stamp_alone(constraint):
+    """The other half of the rule above, and the one that keeps it useful.
+
+    If any edit reset the stamp, a rulebook tidy-up would put every constraint
+    back at the top of the sweep and the ordering would carry no information.
+    Only the check's own text invalidates its verification.
+    """
+    await rulebooks_svc.update_rule(
+        constraint["rule"], constraint["uid"],
+        why="act_runner picks the shell, and the image's SHELL directive "
+            "applies to the build, not to `run:`.",
+        expires_when="the runner grows a shell setting",
+    )
+    row = await _row(constraint["rule"])
+    assert row.verified_at is not None
+    assert row.why.startswith("act_runner picks the shell")
diff --git a/tests/test_services_rulebooks.py b/tests/test_services_rulebooks.py
index b7de1ad..69aba3b 100644
--- a/tests/test_services_rulebooks.py
+++ b/tests/test_services_rulebooks.py
@@ -392,3 +392,57 @@ def test_an_unknown_tier_falls_back_to_binding():
     assert _valid_tier("Conditional") == "always_on"
     assert _valid_tier("") == "always_on"
     assert _valid_tier("occasionally") == "always_on"
+
+
+# ── verify_with / expires_when (milestone 312) ──────────────────────────
+
+def test_a_rule_with_no_check_says_nothing_about_verification():
+    """The empty case is the COMMON case, and it must stay silent.
+
+    Most rules are decisions: they have no truth value and there is nothing to
+    go and check. If a brief carried `last_verified` for those too, the signal
+    would be worthless — every rule would look like something someone ought to
+    be verifying, and the handful that genuinely rot would stop standing out.
+    """
+    from scribe.services.rulebooks import last_verified_label, rule_brief
+
+    rule = fake_rule()
+    assert last_verified_label(rule) is None
+    assert "last_verified" not in rule_brief(rule)
+
+
+def test_an_unverified_constraint_reads_never_rather_than_null():
+    """#2483 again: a null key reads as a capability going unused. "never" is
+    a different and much stronger claim — this rule asserts a fact about
+    someone else's software and nobody has ever confirmed it."""
+    from scribe.services.rulebooks import last_verified_label, rule_brief
+
+    rule = fake_rule(verify_with="cat CI-runner/renovate/config.js")
+    assert last_verified_label(rule) == "never"
+    assert rule_brief(rule)["last_verified"] == "never"
+
+
+def test_a_verified_constraint_reports_the_date_it_was_checked():
+    """A date, not a stamp — the question is "how old is this", the same call
+    rule_brief makes for updated_at."""
+    from scribe.services.rulebooks import last_verified_label
+
+    rule = fake_rule(
+        verify_with="cat CI-runner/renovate/config.js",
+        verified_at=datetime(2026, 8, 27, 11, 46, tzinfo=timezone.utc),
+    )
+    assert last_verified_label(rule) == "2026-08-27"
+
+
+def test_the_check_text_itself_never_enters_a_listing():
+    """A listing says WHICH rules can rot, not how to test them. The check can
+    be a long command; multiplied across an always-on set it is the same bloat
+    `why` and `how_to_apply` are kept out of a brief to avoid."""
+    from scribe.services.rulebooks import rule_brief
+
+    out = rule_brief(fake_rule(
+        verify_with="a very long command " * 20,
+        expires_when="the runner learns a new shell",
+    ))
+    assert "verify_with" not in out
+    assert "expires_when" not in out