Stop re-reading the whole prompt every turn, and let a lost run carry on

M01, the hundred-turn campaign, is the one REQUIRED test still
outstanding. Everything here is about it finishing, and being worth
believing when it does. No requirement changed, no acceptance test was
retired or relaxed, and M11 §P.1's "no performance requirement" still
stands: what changed is the cost of a turn, not what a turn contains.

An inference server caches a prompt by its prefix. The history window
gave up its oldest action every turn, which changed the prompt near the
front and threw that cache away, so nearly the whole prompt was
reprocessed every turn however little had actually changed. The window
now snaps the oldest depth to a block and holds it, stepping every few
turns. Measured on real builder output at an 8,192-token budget: 124.0s
per turn against 362.4s. The cost is history depth, bounded by
TRIM_FRACTION at a quarter of the window, which is the dial between
recent history and speed.

A run that dies no longer starts again from turn one. m11_long_run
checkpoints resume.json after the prologue, after every scheduled step
and after every turn, and --resume reattaches to the same campaign. A
finished run deletes it, so the file's presence means an unfinished run
and starting fresh over one is refused. The model timeout is an option
rather than a hard-coded 600s, a turn that overruns is a failed turn
instead of an unhandled exception that ends the run with no summary,
and a run that has stopped producing turns writes its evidence and
stops.

Two checks could not fail. M04's planted clue went into an add_fact
"detail" key that the event does not define, so it was dropped and
fact_still_in_state could never be true; it is now in "value" and
proved at turn one, which stops a run measuring nothing for hours.
m11_browser degraded silently without a narrator into two failures that
read exactly like a product regression, and now requires one, with
--no-narrator as an explicit opt-out that marks the run partial.

Window discovery speaks Ollama's native API, so against vLLM or
llama.cpp's own server the window goes unverified and the budget
uncapped -- M11's own failure mode reached by another route.
context_window_override lets the operator state what they launched the
server with, and is used only where discovery left a hole: a verified
window always wins, so a declaration can lower an unknown ceiling into
existence and never raise a known one. "verified" still means the
server answered, so window_verified in a turn's provenance keeps the
meaning M11's report counts on.

planning/README.md said the M11 tree was staged rather than committed,
in two places; it was committed and signed. Planning package v3.8.

Backend 1,376 passed, 17 skipped, 0 failed; frontend 161; lint and
build clean. Every M11 harness re-run on this tree: browser 38/0/0,
offline 23/0, identity clean, contrast unchanged, recovery 14/0 on a
small bundle. M01 itself has not been run.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01E9LiyxBxnMTXV2wRjdyDGB

backend/tests/test_m11_long_run_resume.py

@@ -0,0 +1,225 @@
+"""The long run's resume checkpoint, and the refusals that protect its evidence.
+
+M11's release campaign was lost twice over: once to a host crash at turn 97, and
+again to the fact that starting the harness a second time began a new campaign
+rather than continuing the old one. `tools/m11_long_run.py` now checkpoints
+`resume.json` and can be pointed back at it.
+
+These tests exercise that logic without a narrator, a server or a database,
+because none of it needs one: the checkpoint is a file, and the decisions made
+around it are decisions about files. What they cannot prove is that a resumed
+campaign continues correctly against a real application — that is what the run
+itself proves, and §G of the M11 report is where it is reported.
+"""
+import json
+
+import pytest
+
+from tools import m11_long_run as lr
+
+
+class FakeServer:
+    """Enough of `Storyteller` for the checkpoint: it records process starts."""
+
+    def __init__(self, starts=1):
+        self.starts = starts
+
+
+@pytest.fixture
+def run(tmp_path):
+    made = lr.Run(FakeServer(), tmp_path, turns_target=100)
+    yield made
+    made.timeline.close()
+
+
+# --------------------------------------------------------------- checkpoint
+
+def test_a_checkpoint_carries_what_a_resume_needs(run, tmp_path):
+    run.adv = 7
+    run.accepted = 41
+    run.beat = 44
+    run.completed_steps = {7, 14, 21}
+    run.save_resume()
+
+    saved = json.loads((tmp_path / lr.RESUME_FILE).read_text())
+    assert saved["adventure"] == 7
+    assert saved["accepted"] == 41
+    assert saved["beat"] == 44
+    assert saved["completed_steps"] == [7, 14, 21]
+    assert saved["server_starts"] == 1
+    assert saved["turns_target"] == 100
+
+
+def test_the_checkpoint_is_replaced_rather_than_appended(run, tmp_path):
+    run.adv = 7
+    run.accepted = 1
+    run.save_resume()
+    run.accepted = 2
+    run.save_resume()
+
+    assert json.loads((tmp_path / lr.RESUME_FILE).read_text())["accepted"] == 2
+    # The temporary name it is written under must not survive the rename.
+    assert not (tmp_path / (lr.RESUME_FILE + ".tmp")).exists()
+
+
+def test_a_checkpoint_round_trips_into_a_later_session(run, tmp_path):
+    run.adv = 7
+    run.accepted = 41
+    run.beat = 44
+    run.completed_steps = {7, 14}
+    run.elapsed_before = 100
+    run.save_resume()
+    saved = json.loads((tmp_path / lr.RESUME_FILE).read_text())
+
+    later = lr.Run(FakeServer(starts=3), tmp_path, turns_target=100)
+    try:
+        later.adopt(saved)
+        assert later.adv == 7
+        assert later.accepted == 41
+        assert later.beat == 44
+        assert later.completed_steps == {7, 14}
+        assert later.resumed is True
+        # Run time accumulates across sessions rather than restarting.
+        assert later.elapsed_before >= 100
+        assert later.elapsed() >= 100
+    finally:
+        later.timeline.close()
+
+
+def test_a_resumed_session_appends_to_the_existing_timeline(run, tmp_path):
+    run.adv = 7
+    run.note("turn", text="the first session")
+    run.timeline.close()
+
+    later = lr.Run(FakeServer(), tmp_path, turns_target=100)
+    try:
+        later.note("resumed", adventure=7)
+    finally:
+        later.timeline.close()
+
+    lines = (tmp_path / "timeline.jsonl").read_text().strip().splitlines()
+    assert [json.loads(line)["kind"] for line in lines] == ["turn", "resumed"]
+
+
+# ------------------------------------------------------------- the decision
+
+def test_a_clean_directory_starts_a_run(tmp_path):
+    assert lr._resume_state(
+        tmp_path / lr.RESUME_FILE, tmp_path / "timeline.jsonl", False) is None
+
+
+def test_an_unfinished_run_is_not_overwritten(tmp_path):
+    resume_path = tmp_path / lr.RESUME_FILE
+    resume_path.write_text(json.dumps({"adventure": 7, "accepted": 41}))
+
+    refusal = lr._resume_state(resume_path, tmp_path / "timeline.jsonl", False)
+    assert isinstance(refusal, str)
+    assert "--resume" in refusal
+
+
+def test_a_recorded_run_with_no_checkpoint_is_not_reused(tmp_path):
+    """A run that recorded something and then died before its first checkpoint.
+    Starting here would put a second campaign in the same timeline."""
+    timeline = tmp_path / "timeline.jsonl"
+    timeline.write_text(json.dumps({"kind": "settings"}) + "\n")
+
+    refusal = lr._resume_state(tmp_path / lr.RESUME_FILE, timeline, False)
+    assert isinstance(refusal, str)
+    assert "second campaign" in refusal
+
+
+def test_a_run_that_recorded_nothing_leaves_the_directory_usable(tmp_path):
+    """A server that never came up opens the timeline and writes no line to it.
+    Nothing was written that a fresh run could collide with."""
+    (tmp_path / "timeline.jsonl").write_text("")
+
+    assert lr._resume_state(
+        tmp_path / lr.RESUME_FILE, tmp_path / "timeline.jsonl", False) is None
+
+
+def test_resuming_returns_the_checkpoint(tmp_path):
+    resume_path = tmp_path / lr.RESUME_FILE
+    resume_path.write_text(json.dumps({"adventure": 7, "accepted": 41}))
+
+    prior = lr._resume_state(resume_path, tmp_path / "timeline.jsonl", True)
+    assert prior["adventure"] == 7
+    assert prior["accepted"] == 41
+
+
+def test_resuming_nothing_is_refused_rather_than_started_fresh(tmp_path):
+    refusal = lr._resume_state(
+        tmp_path / lr.RESUME_FILE, tmp_path / "timeline.jsonl", True)
+    assert isinstance(refusal, str)
+    assert "no resume.json" in refusal
+
+
+def test_an_unreadable_checkpoint_is_refused(tmp_path):
+    resume_path = tmp_path / lr.RESUME_FILE
+    resume_path.write_text("{not json")
+
+    refusal = lr._resume_state(resume_path, tmp_path / "timeline.jsonl", True)
+    assert isinstance(refusal, str)
+    assert "cannot read" in refusal
+
+
+def test_a_checkpoint_naming_no_campaign_is_refused(tmp_path):
+    resume_path = tmp_path / lr.RESUME_FILE
+    resume_path.write_text(json.dumps({"accepted": 41}))
+
+    refusal = lr._resume_state(resume_path, tmp_path / "timeline.jsonl", True)
+    assert isinstance(refusal, str)
+    assert "names no campaign" in refusal
+
+
+# ----------------------------------------------------------------- timeouts
+
+def test_the_harness_waits_longer_than_the_application_does(tmp_path):
+    """Otherwise the socket closes before the application can report the failure
+    inside the stream, and a real error is recorded as a transport one."""
+    server = lr.Storyteller(tmp_path / "campaign.db", tmp_path / "server.log",
+                            turn_timeout=1800)
+    assert server.stream_timeout > server.turn_timeout
+
+
+def test_the_default_timeout_is_inside_the_settings_bound():
+    """`app/schemas.py` bounds model_timeout_seconds at 30..3600."""
+    assert 30 <= lr.DEFAULT_TURN_TIMEOUT <= 3600
+
+
+# ----------------------------------------------------------------- schedule
+
+def test_every_scheduled_operation_has_its_own_turn(tmp_path):
+    """The steps are keyed by turn number, which is what lets a completed one be
+    remembered across a resume: two are called `retry` and two `restart`, so a
+    name does not identify one."""
+    plan = lr._schedule(100)
+    assert len(plan) == len(set(plan)) == 12
+    assert sorted(plan)[0] >= 1
+    assert max(plan) < 100
+    names = list(plan.values())
+    assert names.count("restart") == 2
+    assert names.count("retry") == 2
+
+
+# --------------------------------------------------------------- the clue
+
+def test_the_planted_clue_uses_a_field_add_fact_actually_carries():
+    """M04's state half turns on the clue text reaching the stored fact.
+
+    `add_fact` requires `predicate` and accepts `subject`, `object`, `value` and
+    `fact_id`. A key it does not define is dropped, and the correction still
+    succeeds — so a clue planted into the wrong key leaves a fact asserting
+    nothing, and `_recall` reports a recall failure the application did not
+    cause. This test fails against the `detail` key that used to be sent.
+    """
+    from app.narrative.events import SPECS
+
+    spec = SPECS["add_fact"]
+    allowed = {"type"} | set(spec["required"]) | set(spec["optional"])
+    assert set(lr.CLUE_FACT) <= allowed, (
+        f"{set(lr.CLUE_FACT) - allowed} is not carried by add_fact")
+
+
+def test_the_planted_clue_carries_the_sentinel_recall_looks_for():
+    assert lr.CLUE_SENTINEL in lr.CLUE_FACT["value"]
+    assert lr.CLUE in lr.CLUE_FACT["value"]