feat(rules): the instruction surfaces say to RETRIEVE a rule, not only to receive one (#3523)

Every instruction surface told a session to load the always-on rules and
stopped there. None said the loaded set is partial, so an empty one read as
"no rule applies" when it only ever meant "none was pushed" — different
claims, and only one of them has been checked.

That is #2198's asymmetry one level in. The earlier defect was trusting the
SessionStart push over the explicit pull; this is trusting the resident TIER
as if it were the whole rulebook.

It is also why the always-on tier was the only one that worked, on any install
rather than this one (rule 115): a rule nothing retrieves must be resident to
bind at all, and a resident rule costs tokens in every session forever — so a
rulebook that only delivers cannot grow past what one session holds.
Retrieval lifts that ceiling, and it fires only if something asks. A
tool-choice reflex asks least of all (#3476, #161).

The same obligation now lands on all three session-start surfaces, because
rule 119 makes them the specification jointly and a surface stating it
differently IS the product behaving differently (#2497). Pinned by
test_every_session_start_surface_states_the_conditional_retrieval, mirroring
the pull test beside it.

THE BUDGET TRADE. _INSTRUCTIONS sat at 1978 against a 2000 test budget, and
its own comment says an addition there is a trade, never an append. Bought the
new clause by trading out "Processes are saved procedures (follow verbatim)"
and "Deletes are trash-recoverable" — both already in DISPLACED_TOPICS and
already stated on a delivered surface, and both per-tool guidance, which by
this block's doctrine belongs in the tool docstring. Now 1976. Recorded in the
comment above the block so it is not silently reversed.

Plugin version minted: shipped plugin content moved.

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

tests/test_instruction_surfaces_agree.py

@@ -195,6 +195,46 @@ def test_displaced_topics_live_on_a_delivered_surface():
     )
 
 
+# The SECOND pull (milestone 333 step 3). `list_always_on_rules()` fetches the
+# resident tier; this one says that tier is not all of them, and that a
+# conditional rule has to be gone looking for. However a surface words the
+# surrounding prose, it names the call.
+RETRIEVE = 'content_type="rule"'
+
+
+def test_every_session_start_surface_states_the_conditional_retrieval():
+    """The push/pull asymmetry, one level in.
+
+    The tests above pin that a session PULLS the resident rules rather than
+    trusting the SessionStart push. This pins the same shape between the two
+    TIERS: an always-on rule is delivered, a conditional one is retrieved, and
+    a surface that states only the first leaves a session reading its loaded
+    set as the whole rulebook.
+
+    That reading is wrong in the direction that costs something. "Nothing was
+    pushed" and "no rule applies" are different claims, and only one of them
+    has been checked — the same asymmetry as #2198, now between tiers instead
+    of between channels.
+
+    It is also what made the always-on tier the only one that worked, on any
+    install rather than this one (rule 115). A rule nothing retrieves has to be
+    resident to bind at all, so every rule worth keeping becomes resident; and
+    a resident rule costs tokens in every session forever, so a rulebook that
+    only delivers cannot grow past what one session can hold. Retrieval is what
+    lifts that ceiling — and it only fires if something asks.
+    """
+    missing = []
+    for path in SESSION_START_SURFACES:
+        if RETRIEVE not in path.read_text():
+            missing.append(str(path.relative_to(ROOT)))
+    assert not missing, (
+        f"these surfaces state the always-on pull but never tell the agent to "
+        f"retrieve a conditional rule ({RETRIEVE}): {missing}. A session that "
+        f"reads its loaded set as the whole rulebook will act on \"I was not "
+        f"told\" as if it meant \"there is no rule\" (milestone 333 step 3)."
+    )
+
+
 def test_no_surface_names_the_push_without_stating_the_pull():
     """The exact shape #2497 took.