llm-ingestion-okf/docs/2026-09-04-k3-arm-c.md

# K3 with Arm C beside the baseline, 2026-09-04

Two numbers on the same footing, so a threshold can be set afterwards. **No
threshold is set here**, and none is implied: the K3 method
(`docs/2026-09-02-k3-k4-k5-metode.md`) declares none, and inventing one inside
the work that produces a measurement is fitting the bar to the number.

Counts only. The corpus is public procurement material, but nothing here needs
a document body or a full filename list to be checkable.

## Arm C is not defined upstream of this document

`docs/2026-09-02-k3-k4-k5-metode.md` contains **zero** occurrences of the word
"arm" (`grep -c -i "arm"` -> `0`). Neither Arm A nor Arm B nor Arm C is defined
there. Where the three names actually occur:

| arm | where it is named | what it says |
|-----|-------------------|--------------|
| A | `docs/2026-08-29-konverteringsarmen-arm-a.md:1` | "Conversion arm (arm A): pandoc vs markitdown vs docling" |
| B | `tests/test_segmented_inbox.py:509`, a code comment | "arm B cannot execute without this" |
| C | `docs/2026-09-03-k2-bundle-rebuild.md:171` | "Reported, not fixed: Arm C is its own decision." |

So Arm C had no definition to conform to. **The definition measured here is
this document's own** and is marked as such everywhere it appears, including in
the tool's `--help`:

> **Arm C** = Arm B's mechanical rules, plus one deterministic rule that cuts
> any proposed span longer than a declared cap at the nearest paragraph
> boundary at or before it, the whole document counting as one span when the
> rules find no boundary at all.

One rule and not two, deliberately. The two failure modes
`docs/2026-09-03-k2-bundle-rebuild.md` measured -- a PDF with no outline
(Bilag 9.1, 217 472 characters) and a PDF whose headings are its table of
contents so the trailing segment absorbs the body (Bilag 3.1, Bilag 1) -- are
the same failure of size, and a second rule aimed at each would confound which
one moved the number.

**What Arm C deliberately does not change:** the region before the first
candidate is still covered by no segment. That is a real coverage defect -- the
baseline's blind rater named it -- and fixing it here would have put two
changes behind one measurement.

### The cap, declared before any Arm C proposal was judged

`max_segment_chars = 20000`, fixed from Arm B's own output and not from a K3
outcome:

- Arm B's segment-body sizes over the whole K2 bundle, `n = 629` concepts:
  p50 441, p75 1 215, p90 2 972, p95 6 099, mean 2 698, max 217 472.
- 20 000 is ~3.3x that p95, so what Arm B already produces is left alone:
  measured **15 of 629** concepts (2.4 %) exceed it.
- At the corpus's measured ~2.20 characters per token, 20 000 characters is
  ~9 100 tokens -- an order of magnitude below the 100 000-token line that
  motivated the rebuild.

**No sensitivity sweep was run.** Sweeping the cap and keeping the value that
produced the best K3 number would fit the parameter to the verdict.

## The standard profile did not move

`--max-segment-chars` defaults to `0`, which is off. A test writes the artifact
with and without the flag at `0` and compares bytes.

The bundle a consumer is running against was hashed before the work started and
again after the Arm C bundle was built, whole tree, 1108 files:

```
find K2-bundle-20260903 -type f | sort | xargs shasum -a 256 | shasum -a 256
9cd745194346cda0c70eab9c7136fa44506203bbe85bc17d7eff2766c6e9b4d1   (before)
9cd745194346cda0c70eab9c7136fa44506203bbe85bc17d7eff2766c6e9b4d1   (after)
```

Arm C was built to its own output: `K2-bundle-armc-20260904/`, plans in
`K2-plans-armc-20260904/`.

## K3, the two numbers side by side

Same 12 documents, same canonical hash order, same four categories, same
tie-break (coarse before fine before duplicate). First rater
`claude-opus-5/okf-session-89`, labels written to file before any blind rating
was read.

| category | arm B (baseline) | arm C |
|------------|------------------|-------|
| too coarse | 8 | 8 |
| too fine | 4 | 4 |
| duplicate | 0 | 0 |
| correct | 0 | 0 |

Both sum to `n = 12`. No replacement was needed; the reconstructed sample is
the baseline's own -- a known-positive check, **4 of the 12 have an empty
Arm B proposal**, which is what `docs/2026-09-02-k3-k4-k5-baseline.md` reported.

**Arm C changed the proposal on 6 of the 12 documents and moved the category
counts by zero.** That is the finding, not a null result: the size rule makes
concepts smaller, which is what a consumer asked for, and K3 does not measure
size. K3 asks whether a boundary falls where a unit of knowledge begins, and an
arithmetic cut does not know where one begins.

### This first rater does not reproduce the 2026-09-02 baseline row

The 2026-09-02 baseline recorded 7 / 3 / 1 / 1 on the same twelve Arm B
proposals. This session's first rater records **8 / 4 / 0 / 0**. The proposals
did not change; the rater did. Two of the differences are traceable:

- The baseline's single `correct` was contested by its own blind rater, who
  named a chapter absorbed into the preceding segment and an introduction
  covered by no segment. That document is `Bilag 3.8 - Overvannsutredning`, and
  this rater checked at that resolution: its chapter 2 (`Planlagt situasjon`,
  offset 6325) lies wholly inside the span 4064-6886 of the segment opened by
  section 1.3. Rated **too coarse**.
- The baseline's single `duplicate` is not reproduced. Where a table-of-contents
  line and a body heading produce two segments with the same title, this rater
  read the two as different content -- a contents listing is not the section it
  lists -- so `too fine` rather than `duplicate`.

The baseline said its `too coarse` count was **a floor rather than an
estimate**. This re-rating is consistent with that and does not overturn it:
same-family raters, small `n`, and a difference in reading rather than in
evidence.

## Blind second rater, per arm

`n_blind = 6` per arm: positions 0, 2, 4, 6, 8, 10 of the sample's canonical
hash order. Two separate raters, one per arm, each in its own context, each
given only the proposals, the source evidence, the four category definitions and
the tie-break -- and neither given the other arm, so an arm C rating cannot
anchor on an arm B one.

| arm | agreement | the one disagreement |
|-----|-----------|----------------------|
| B (baseline) | **5/6** | position 6, `Bilag 3.8 - Overvannsutredning` |
| C | **5/6** | position 6, the same document, the same proposal |

The two arms agree with their blind raters at the same rate, and the blind
raters' own six-document counts are identical to each other: 4 too coarse,
1 too fine, 1 correct, in **both** arms. Two rater instances that never saw
each other's arm reached the same distribution -- which is the same headline as
the twelve-document counts, reached independently.

**The disagreement is the same document as the baseline's, with the roles
reversed.** On 2026-09-02 the first rater called `Bilag 3.8` correct and the
blind rater called it too coarse. Here the first rater calls it too coarse and
both blind raters call it correct, on the grounds that "the six segments track
the document's own numbered subsections (1.1-1.3, 3.1-3.3), each opening
exactly at its heading."

That is true and it is not the whole document. The first rater's evidence is
narrower and checkable: the document's chapter 2, `Planlagt situasjon`, opens at
offset 6325, and the segment opened by section 1.3 spans 4064-6886 -- so
chapter 2 lies wholly inside it and has no segment of its own. Both arms
propose this identical segmentation, because the document is under the cap and
Arm C left it untouched.

**The asymmetry is the finding, not the ratio.** In both the baseline and this
run, the disagreement was resolved by a specific offset in one direction and by
a general impression in the other, and the specific direction was always
`too coarse`. That is what the baseline meant by calling its `too coarse` count
a floor. It is still a floor.

**No verdict is revised.** A first rater who edits a label after reading the
second rater's is not being second-rated at all.

**Cohen's kappa is deliberately not reported**, for the reason the method gives:
at four categories and `n_blind = 6` a chance-corrected statistic would look
more rigorous than percent agreement while being less informative.

**The independence caveat stands and is not softened.** All raters here are
instances of the same model family, so agreement overstates independence,
probably substantially.

## What did move, with denominators

Nothing in this section is K3. It is reported because it is what the consumer's
finding was actually about.

| figure | arm B | arm C |
|--------|-------|-------|
| documents with something to propose | 28/39 | 33/39 |
| documents proposing nothing | 11/39 | 6/39 |
| proposed entries | 618 | 674 |
| concepts in the bundle | 629 | 680 |
| `index.md` files | 478 | 483 |
| concepts carrying `adjudication` | 618/629 | 674/680 |
| concept body characters, median | 441 | 510 |
| concept body characters, max | **217 472** | **19 988** |
| concepts over 100 000 characters | 4 | **0** |
| concepts over 20 000 characters | 15 | **0** |
| wall time, whole run | 784.29 s | 820.55 s |

Door-level counts are unchanged, as they must be -- Arm C touches segmentation,
not extraction: `N = 43`, merged 39/43, coded rejections 4/43
(`extractor_unknown` 3, `extractor_empty_pdf` 1), run exited `0`.

The 6 documents that still propose nothing under Arm C are the ones already
under the cap. Arm C fires on size; where size is not the problem it has nothing
to say, and a one-entry plan would only dress a single concept in a plan file.

### The three documents the order named

Concept bodies in the two bundles, not plan spans:

| document | arm B concepts | arm B largest | arm C concepts | arm C largest |
|----------|----------------|---------------|----------------|---------------|
| Bilag 3.1 | 34 | 180 604 | 43 | 19 946 |
| Bilag 1 | 18 | 142 667 | 27 | 19 920 |
| Bilag 9.1 | 1 | 217 472 | 14 | 19 988 |

## A finding this measurement did not go looking for

**Bilag 9.1 -- the largest concept in the bundle, and the one the consumer
flagged -- is an extraction failure, not a segmentation failure.** Measured on
its extracted text: **95.1 %** of the 217 470 characters are `(cid:N)` glyph
codes (27 978 of them), and **98** alphabetic words of four or more letters
survive in the whole document. The PDF's fonts carry no usable ToUnicode
mapping, so the text this repository persisted is very largely undecodable.

This bounds what any arm can claim about that document. Its category in both
arms rests on document identity -- an agreement that is transferred, plus
attachments -- and not on readable content, so it contributes one count to each
arm and no evidence that discriminates between them. Arm C divides unreadable
text into 14 pieces of unreadable text.

Reported, not fixed. A CID-mapped PDF is an extraction question, and the
extraction warning this library already emits ("figures are not represented")
does not cover it: this document's *prose* did not survive either.

## What this does not measure

- **No threshold**, on K3 or anything else. Two numbers, so the operator can set
  one.
- **K4 and K5 are untouched.** No adjudication timing was re-run and no SPEC
  § 5.1 provenance was re-counted; the baseline's figures stand.
- **Arm C's bundle was not re-measured against the consumption contract**, and
  its rebuild-equals-incremental property was not re-run. Both are properties of
  the harness, unchanged by this flag.
- **`pptx`, `odt`, `rtf` still have denominator 0** in this corpus. Unmeasured,
  not passing.
- The cap was **not swept**. One value, declared first, measured once.

## Reproducing

```
PLANS=~/corpora/okf-telling-20260829/K2-plans-armc-20260904; mkdir -p "$PLANS"
i=0
for f in ~/corpora/okf-telling-20260829/K2/trinn1/*; do
  i=$((i+1)); b=$(basename "$f")
  .venv/bin/python tools/okf_propose_segments.py "$f" \
    --out "$PLANS/$(printf '%02d' $i).json" \
    --path-prefix "${b%.*}" --proposed-at 2026-09-04T00:00:00Z \
    --max-segment-chars 20000
done
.venv/bin/python tools/okf_corpus_run.py \
  --corpus ~/corpora/okf-telling-20260829/K2/trinn1 \
  --report ~/corpora/okf-telling-20260829/K2-bundle-armc-20260904-report.md \
  --bundle ~/corpora/okf-telling-20260829/K2-bundle-armc-20260904 \
  --ingested-at 2026-09-04T00:00:00Z --plans-dir "$PLANS" \
  --bundle-id k2-trinn1-armc-20260904 --okf-version 0.2
```

Converter as the harness resolved it: the vendored `pypandoc` binary, version
**3.9** -- not the host's 3.10.2.

## Appendix: the twelve raw verdicts, both arms

Blind-subset positions are marked `*`; those six are the ones with a second
rater. Documents are named by their short corpus label.

| pos | document | arm B | arm C | arm B blind | arm C blind |
|-----|----------|-------|-------|-------------|-------------|
| 0 * | Bilag 9.1 (Avtale som tiltransporteres) | too coarse | too coarse | too coarse | too coarse |
| 1 | Bilag 3.2.2 (RIG-R02 geoteknisk) | too coarse | too coarse | - | - |
| 2 * | Bilag 1.1 (Generelle tekniske krav) | too coarse | too coarse | too coarse | too coarse |
| 3 | Bilag 7 (Prisskjema, `xlsx`) | too coarse | too coarse | - | - |
| 4 * | Vedlegg 5 (Begrunnelse for krav) | too coarse | too coarse | too coarse | too coarse |
| 5 | Vedlegg 3 (Erfaringsoversikt) | too fine | too fine | - | - |
| 6 * | Bilag 3.8 (Overvannsutredning) | too coarse | too coarse | **correct** | **correct** |
| 7 | Bilag 1.3 (BIM-manual) | too fine | too fine | - | - |
| 8 * | Bilag 3.4 (Premissdokument bygningsfysikk) | too coarse | too coarse | too coarse | too coarse |
| 9 | Bilag 5 (SHA-plan) | too coarse | too coarse | - | - |
| 10 * | Vedlegg 1 (Soknadsbrev) | too fine | too fine | too fine | too fine |
| 11 | Dokument for avtaleinngaelse | too fine | too fine | - | - |

The six documents whose arm B and arm C proposals are **byte-identical** are
positions 5, 6, 7, 9, 10 and 11: each is under the cap, so Arm C left it
untouched and the two verdicts are the same judgement of the same artifact, not
two judgements that happened to agree. The six Arm C proposals that are
genuinely new are positions 0, 1, 2, 3, 4 and 8 -- and **none of them changed
category**.

The first rater's evidence, per position, in one line each:

- 0 -- 14 size-cut parts of a document whose text is 95.1 % undecodable; see
  the finding above. Arm B emitted it as one 217 470-character concept.
- 1 -- entry 20 fuses section 5.2, chapter 6 and the appendices (22 281
  characters); Arm C shortens that entry to 17 756 and adds a 4 525-character
  part, and the fusion is still there.
- 2 -- nine numbered chapters, listed in the document's own contents, in one
  concept; Arm C cuts at a page footer at ~19 164, fusing roughly six chapters
  then three.
- 3 -- one entry over `F.1 Prissammenstilling`, the maintenance-agreement table,
  `F.2 Regningsarbeider` and the options table; Arm C's seven parts align with
  none of those four, and its first entry is a 34-character sliver.
- 4 -- background, the quoted regulation and the assessment in one concept;
  Arm C's cut separates the appendix table but leaves the three fused.
- 5 -- three reference forms shredded into 21 entries.
- 6 -- chapter 2 absorbed into the span of section 1.3; see the blind-rater
  disagreement above.
- 7 -- nine spurious segments cut out of the table of contents, above 36 body
  segments that do track the document.
- 8 -- 24 pages in one concept; Arm C's three parts break a sentence across
  parts 2 and 3.
- 9 -- entry 5 fuses chapters 2, 3, 4, 5, 6 and the appendix (8 853 characters),
  and entry 1 is a fragment of the table of contents.
- 10 -- the checklist table cut into 13 fixed-size slices.
- 11 -- the agreement's own head (offsets 0-793) covered by no segment, and the
  signature table emitted as two fragments.