feat(rules): the rule-creation tools ask for approval, and ask what would enforce it (#3557)

Every gate on create_rule and create_project_rule was about SHAPE — rule vs
process vs snippet, one-thing-you-could-violate, general-enough, not-a-dupe.
All of them improve a rule someone has already decided to write. None asked
the prior question: has the person this will bind agreed to be bound by it?

Both docstrings now open with the gate, and with the four things a proposal
carries: what it would require in the words it would carry, its intent, why
now, and how it would be enforced.

The fourth is the one that decides it. "A test, a CI check, a hook, a schema
constraint... or nothing" is a question that sometimes dissolves the rule:
what a test can assert should BE that test, and a rule is what is left when
nothing mechanical can hold the thing. A rulebook grows by default and
shrinks only on purpose.

create_project_rule needs the gate more, not less, and says so: a project
rule is absent from an unfiltered list_rules(), and a conditional one is
absent from session start too, so one written there can bind for months
without ever having been in front of the person it binds.

test_rule_creation_asks_first pins structure, never wording — each element
matches a family of synonyms, and the gate must precede the Args: block,
because a caller who has decided to make the call reads the parameters and
not the prose under them.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_011cPyzNnegXHr5iRMzzy5KJ

tests/test_rule_creation_asks_first.py

@@ -0,0 +1,109 @@
+"""Both rule-creation tools tell the caller to ask before writing (#3557).
+
+WHY THIS EXISTS
+
+Every other gate on `create_rule` and `create_project_rule` is about SHAPE:
+is this a rule or a process, is it one thing you could violate, is it general
+enough for a rulebook, is it a near-duplicate. All of those improve a rule
+someone has already decided to write. None of them asks the prior question —
+whether the person the rule will bind has agreed to be bound by it.
+
+That question has to be asked at the tool, because the tool is the last
+surface a caller reads before the write, and because the write is not
+reversible in the way it looks. A rule that exists is not a proposal that
+happens to be recorded: it is a standing instruction the operator must first
+DISCOVER and then argue with, and the tiering makes discovery unreliable by
+design — a conditional rule is never read aloud at session start, and a
+project-scoped rule does not appear in an unfiltered `list_rules()` at all.
+So the cheapest moment to ask is the only good one.
+
+The fourth element of a proposal — how the rule would be ENFORCED — is not
+ceremony. It is the gate that sometimes dissolves the rule: a thing a test
+can assert should be that test, and a rule is what is left over when nothing
+mechanical can hold it. A rulebook grows by default and shrinks only on
+purpose, so the question that prevents a rule earns more than any question
+that improves one's wording.
+
+WHAT THIS PINS, AND WHAT IT DOES NOT
+
+STRUCTURE, never wording — the same bargain the disambiguator guard (#3123)
+strikes next door. Each concept is matched against a family of synonyms, so
+the paragraphs stay free to be rewritten, reordered or sharpened; only
+DELETING one fails. Pinning phrasing would make every improvement a red
+build, and a test that punishes editing is a test someone deletes.
+
+It cannot tell whether an agent actually asks. Nothing in a docstring can.
+It catches the regression that really happens: guidance tidied away in a
+later pass by someone who read it as throat-clearing in front of the Args.
+"""
+import pytest
+
+from tests.helpers import tool_doc as _doc
+
+# Both surfaces, because the one that needs it most is the one that looks
+# minor. A project rule is the least visible record the system can hold —
+# absent from an unfiltered list_rules(), and absent from session start too
+# whenever it is conditional — so the surface that writes one carries the
+# larger risk while reading as the smaller act.
+_SURFACES = [
+    ("scribe.mcp.tools.rulebooks", "create_rule"),
+    ("scribe.mcp.tools.rulebooks", "create_project_rule"),
+]
+
+# The four things a proposal carries, each as a family of ways to say it.
+# A docstring satisfies an element by containing ANY member — that is the
+# room left for rewriting. The families deliberately exclude bare words a
+# docstring would contain by accident ("why", "how", "reason"), which would
+# make the assertion pass on prose that says nothing of the kind.
+_ELEMENTS = {
+    "the approval gate itself": (
+        "proposal", "propose", "approv", "unprompted", "wait for an answer",
+        "not yours to call",
+    ),
+    "the rule's intent": ("intent", "what it changes about how work"),
+    "why it is being proposed now": (
+        "why now", "arose_from_id", "the incident", "prompted it",
+    ),
+    "how it would be enforced": ("enforc",),
+}
+
+
+@pytest.mark.parametrize(("module", "name"), _SURFACES)
+@pytest.mark.parametrize("element", sorted(_ELEMENTS))
+def test_a_rule_surface_asks_for_approval_and_its_four_parts(
+    module, name, element
+):
+    """Each of the four proposal elements survives in each docstring."""
+    doc = _doc(module, name).lower()
+    assert any(token in doc for token in _ELEMENTS[element]), (
+        f"{name}'s docstring no longer mentions {element}. A caller reads "
+        f"this immediately before writing a rule that will bind every future "
+        f"session — it is the last place the question can be raised cheaply. "
+        f"Say it in whatever words you like; this guard only checks it is "
+        f"still said. See create_rule's opening for the shape."
+    )
+
+
+@pytest.mark.parametrize(("module", "name"), _SURFACES)
+def test_the_approval_gate_comes_before_the_parameter_contract(module, name):
+    """It has to be read to work, and the Args: block is where reading stops.
+
+    A caller who has decided to make the call skims down to the parameters.
+    Guidance parked below them — or folded into one argument's description —
+    is guidance that arrives after the decision it was meant to inform, which
+    is the same as not being there.
+    """
+    doc = _doc(module, name).lower()
+    args_at = doc.find("args:")
+    assert args_at > 0, f"{name}'s docstring has no Args: block"
+    gate_at = min(
+        (doc.find(t) for t in _ELEMENTS["the approval gate itself"]
+         if doc.find(t) >= 0),
+        default=-1,
+    )
+    assert 0 <= gate_at < args_at, (
+        f"{name} states the approval gate at or after its Args: block "
+        f"(gate {gate_at}, args {args_at}). Move it to the opening — a "
+        f"caller who has already decided to write the rule reads the "
+        f"parameters, not the prose under them."
+    )