feat(consume): give every excerpt the name and the address an answer must cite

The pre-pass delivered the right concept and the answer could not name it.
Measured by portfolio-optimiser 2026-09-08 over three paid arms: the gold
concept came back at rank 1 of 8 on 3 of 3 bundles, and the model answered
correctly on 1 of 3, because a delivered excerpt carried `concept_id`, body
text and nothing the document is known by. The previous session measured the
same gap from the other side: the provenance it had just written into every
concept did not reach the payload at all.

`excerpt_for` now carries `title` unconditionally, and `req_number`, the SPEC
5.1 address `sources` and each locator key (`source_pages`, `source_sheet`,
`source_rows`, `source_lines`, `source_offset`) when the concept has them. A key
the producer did not write stays absent: an empty value would assert that they
wrote an empty one, which is the contract's 6.4 failure.

`sources` is read in BOTH YAML forms, on a measurement rather than a taste. K2
writes the flow form on 629 of 629 concepts; the largest N-bundle writes the
block form on 270 of 270 and carries no locator key at all, so a flow-only
reader delivers that bundle with no address whatsoever. Reading the block form
is not a licence to write it - the emission rule is untouched, because the
line-oriented parser still cannot round-trip a block list. A `sources` value
this reader cannot decode is named (`sources_unreadable`), never dropped into
the same silence as an absent one.

Contract 8 gains the requirement and the checker gains its code
(`excerpt_unnamed`, 15 rules now, was 14): an excerpt a reader cannot name is
one an answer cannot cite, whatever its rank. `req_number`, `sources` and the
locators are SHOULD, not MUST - they are conditional on the producer, and a
bundle whose concepts carry no identifier cannot deliver one.

K2 controls, same question and same k, before against a frozen copy of the tool
at b6a8c8b: the RANKING does not move - the same 8 concept ids in the same
order, identical `text_sha256`, identical `withheld`, identical denominators
(629 = 621 + 8). The FIELD is what moved: payload 108 877 -> 111 744 B
(+2.63 %), budget spent 18 606 -> 20 907 (+287.6 B per excerpt), excerpt
members 9 -> 15, 83 changed lines. The contract document's own bytes moved with
8, so the budget instrument's known-positive moves with it: 10 349 -> 12 049
measured, 10 060 -> 11 719 raw, delta 289 -> 330.

New fixture `tests/fixtures/consume-provenance`: the two address forms and a
concept carrying neither address nor identifier. Purpose-built, because the two
real bundles are complementary and neither exercises both forms.

Suite 1347 (1339 before), ruff clean, mypy src clean.

Co-Authored-By: Claude <claude-opus-5>

tests/fixtures/consume-provenance/blokkform-krav.md

@@ -0,0 +1,15 @@
+---
+type: Krav
+title: Krav 10.2-2 Beredskap
+req_number: Krav 10.2-2
+ingested_at: 2026-09-08T00:00:00Z
+adjudication: proposed
+bundle_id: provenance-fixture
+sources:
+  - resource: https://example.invalid/api/nisosts/1?languageCode=nb
+    title: Fiktiv normal 2024
+---
+
+## Krav
+
+Beredskapsplanen skal oppdateres hvert aar.

tests/fixtures/consume-provenance/flytform-side.md

@@ -0,0 +1,14 @@
+---
+type: reference
+title: Sideoppslag i regelverket
+ingested_at: 2026-09-08T00:00:00Z
+adjudication: proposed
+bundle_id: provenance-fixture
+sources: [{ resource: Fiktivt grunnlag.pdf, title: Fiktivt grunnlag.pdf }]
+source_pages: [4, 6]
+source_offset: [120, 480]
+---
+
+## Sideoppslag
+
+Teksten staar paa sidene fire til seks i det fiktive grunnlaget.

tests/fixtures/consume-provenance/index.md

@@ -0,0 +1,8 @@
+---
+okf_version: 0.2
+bundle_id: provenance-fixture
+---
+
+- [Krav 10.2-2 Beredskap](blokkform-krav.md)
+- [Sideoppslag i regelverket](flytform-side.md)
+- [Notat uten adresse](uten-adresse.md)

tests/fixtures/consume-provenance/uten-adresse.md

@@ -0,0 +1,11 @@
+---
+type: reference
+title: Notat uten adresse
+ingested_at: 2026-09-08T00:00:00Z
+adjudication: proposed
+bundle_id: provenance-fixture
+---
+
+## Notat
+
+Dette konseptet har verken sources, kravnummer eller lokator.

tests/test_okf_consume.py

@@ -29,6 +29,7 @@ import socket
 import subprocess
 import sys
 import unicodedata
+from collections.abc import Mapping
 from pathlib import Path
 
 import pytest
@@ -1615,6 +1616,10 @@ def _synthetic(concept_id: str, title: str, body: str) -> okf_consume.Concept:
         source_file="synthetic.md",
         adjudication="unknown",
         adjudication_present=False,
+        req_number="",
+        sources=(),
+        sources_present=False,
+        locators={},
         frontmatter={},
         body=body,
     )
@@ -2090,3 +2095,136 @@ def test_the_lookup_keeps_the_fused_order_among_the_concepts_it_lifts() -> None:
     assert [concept.concept_id for concept, _, _ in ranked[len(hits) :]] == sorted(
         concept.concept_id for concept in concepts if concept.concept_id not in hits
     )
+
+
+# --- Step 13: the excerpt carries the key the question is asked ON (C1 step 0) -
+
+#: A bundle purpose-built for one measurement: the two SS 5.1 `sources` forms
+#: and a concept carrying neither address nor locator. It exists because the
+#: two real bundles are complementary and neither exercises both forms --
+#: measured 2026-09-08, K2 writes `sources` in FLOW form on 629 of 629 concepts
+#: and carries `req_number` on 0, while the N500 bundle writes BLOCK form on 270
+#: of 270, carries `req_number` on 269 and carries no locator key at all.
+PROVENANCE = PROJECT_ROOT / "tests" / "fixtures" / "consume-provenance"
+PROVENANCE_QUESTION = "Hva krever Krav 10.2-2?"
+
+
+def _provenance_excerpts() -> dict[str, Mapping[str, object]]:
+    # Every concept, not only the delivered ones: the cut is a different
+    # question and would make this measurement depend on a ranking.
+    excerpts: dict[str, Mapping[str, object]] = {}
+    for concept_id in okf_consume.enumerate_concepts(PROVENANCE):
+        excerpt = okf_consume.excerpt_for(
+            okf_consume.read_concept(
+                PROVENANCE / f"{concept_id}.md",
+                bundle_root=PROVENANCE,
+                root_bundle_id="provenance-fixture",
+            )
+        )
+        assert excerpt is not None
+        excerpts[concept_id] = excerpt
+    return excerpts
+
+
+def test_every_delivered_excerpt_names_the_concept_the_answer_would_cite() -> None:
+    # po measured 2026-09-08 (`e7ffe9e`) that the pre-pass delivers the gold
+    # concept at rank 1 and the model still cannot name what it is citing: the
+    # excerpt carried `concept_id` and `text` and no `title`. The ranking found
+    # the document; the delivery dropped the key.
+    payload = okf_consume.build_payload(PROVENANCE, question=PROVENANCE_QUESTION)
+    delivered = payload["excerpts"]
+    assert isinstance(delivered, list)
+    assert delivered, "the cut delivered nothing, so the assertion below is vacuous"
+    for excerpt in delivered:
+        concept = okf_consume.read_concept(
+            PROVENANCE / f"{excerpt['concept_id']}.md",  # type: ignore[index]
+            bundle_root=PROVENANCE,
+            root_bundle_id="provenance-fixture",
+        )
+        assert excerpt["title"] == concept.title  # type: ignore[index]
+        assert excerpt["title"]  # type: ignore[index]
+
+
+def test_an_excerpt_carries_the_identifier_the_question_spells_and_never_invents_one() -> None:
+    excerpts = _provenance_excerpts()
+    assert excerpts["blokkform-krav"]["req_number"] == "Krav 10.2-2"
+    # A concept without the key gets no key. Emitting `""` would assert that the
+    # producer wrote an empty identifier, which is SS 6.4's failure.
+    assert "req_number" not in excerpts["flytform-side"]
+    assert "req_number" not in excerpts["uten-adresse"]
+
+
+def test_a_flow_form_address_and_its_locator_reach_the_excerpt() -> None:
+    excerpt = _provenance_excerpts()["flytform-side"]
+    assert excerpt["sources"] == [
+        {"resource": "Fiktivt grunnlag.pdf", "title": "Fiktivt grunnlag.pdf"}
+    ]
+    assert excerpt["source_pages"] == "[4, 6]"
+    assert excerpt["source_offset"] == "[120, 480]"
+    assert "source_lines" not in excerpt
+
+
+def test_a_block_form_address_reaches_the_excerpt_rather_than_becoming_an_empty_string() -> None:
+    # `parse_frontmatter` SKIPS indented lines, so the block form arrives as
+    # `''` -- present and unreadable. Measured 2026-09-08: 270 of 270 concepts
+    # in the largest N-bundle write it that way, so a reader that only handles
+    # the flow form delivers that bundle with no address at all.
+    excerpt = _provenance_excerpts()["blokkform-krav"]
+    assert excerpt["sources"] == [
+        {
+            "resource": "https://example.invalid/api/nisosts/1?languageCode=nb",
+            "title": "Fiktiv normal 2024",
+        }
+    ]
+
+
+def test_a_concept_with_no_address_and_no_locator_carries_neither_key() -> None:
+    excerpt = _provenance_excerpts()["uten-adresse"]
+    for key in ("sources", "sources_unreadable", *okf_consume.LOCATOR_KEYS):
+        assert key not in excerpt, key
+
+
+def test_an_unreadable_address_is_named_rather_than_dropped(tmp_path: Path) -> None:
+    # The third state. A `sources` value this reader cannot decode is neither an
+    # address nor an absence, and collapsing it into either reports a fact
+    # nobody measured.
+    root = tmp_path / "bundle"
+    _copy_bundle(PROVENANCE, root)
+    target = root / "uten-adresse.md"
+    target.write_text(
+        target.read_text(encoding="utf-8").replace(
+            "bundle_id: provenance-fixture",
+            "bundle_id: provenance-fixture\nsources: not-a-list",
+        ),
+        encoding="utf-8",
+    )
+    concept = okf_consume.read_concept(
+        target, bundle_root=root, root_bundle_id="provenance-fixture"
+    )
+    excerpt = okf_consume.excerpt_for(concept)
+    assert excerpt is not None
+    assert excerpt["sources_unreadable"] is True
+    assert "sources" not in excerpt
+
+
+def test_the_golden_bundle_excerpt_carries_the_address_and_locator_o3_wrote() -> None:
+    payload = okf_consume.build_payload(GOLDEN, question="Hva sier veiledningen om krav?")
+    excerpts = payload["excerpts"]
+    assert isinstance(excerpts, list)
+    by_id = {entry["concept_id"]: entry for entry in excerpts}  # type: ignore[index,union-attr]
+    first = by_id["krav/1-1/foerste-krav"]
+    assert first["title"] == "Foerste krav"
+    assert first["sources"] == [{"resource": "veiledning.md", "title": "veiledning.md"}]
+    assert first["source_lines"] == "[5, 8]"
+    assert first["source_offset"] == "[94, 176]"
+
+
+def test_the_checker_refuses_an_excerpt_that_cannot_be_named() -> None:
+    # The SS 8 update, with its own code: a payload whose excerpts carry no
+    # `title` is the defect po measured, and a checker that passes it certifies
+    # a payload a model cannot cite from.
+    payload = json.loads((SKILL.parent / "references" / "example-payload.json").read_text("utf-8"))
+    assert okf_contract_check.check(SKILL.read_text(encoding="utf-8"), payload).findings == ()
+    del payload["excerpts"][0]["title"]
+    codes = [f.code for f in okf_contract_check.check(SKILL.read_text("utf-8"), payload).findings]
+    assert codes == ["excerpt_unnamed"]