# h05 — One value inside an 1,100-page PDF

| | |
|---|---|
| **Difficulty** | hard (harness-hostile) |
| **Domain** | embedded / documentation retrieval |
| **Probes** | pagination with `fetch_page` `offset` on a huge PDF; the six-fetch bound; saying exactly what was read (manual vs secondary source) |
| **Tools expected** | `web_search` / `find_datasheet` → `fetch_page` with `offset` |
| **Trap** | RM0008 is ~1,100 pages / ~13 MB at st.com. `fetch_page` may time out, be refused, or return the first 6,000 characters of a document whose answer is ~200 pages in. The model must either paginate intelligently (the RCC chapter is early — chapter 7), find a mirror, or admit it only confirmed the value from secondary sources. The value is trivially available on forums, which is exactly what the prompt forbids. |

## Ground truth

**RCC_CFGR: address offset 0x04, reset value 0x0000 0000** (RM0008 §7.3.2 "Clock configuration register (RCC_CFGR)" in Rev 21; RCC base address 0x4002 1000). Section numbering can differ by manual revision; the offset and reset value do not.

> **Verified at grading time (2026-09-11, by the grader).** The rubric's ground truth is
> correct as written — no correction needed. st.com timed out for the grader too, so the
> manual was pulled from the Espruino mirror of RM0008
> (`https://www.espruino.com/datasheets/STM32F103xC_ref.pdf`, DocID13902 **Rev 15**,
> 13,016,697 bytes) and read with `pdftotext`. §7.3.2 (low/medium/high/XL-density RCC)
> reads verbatim: "Clock configuration register (RCC_CFGR) / Address offset: 0x04 /
> Reset value: 0x0000 0000 / Access: 0 ≤ wait state ≤ 2, word, half-word and byte access /
> 1 or 2 wait states inserted only if the access occurs during clock source switch."
> §8.3.2 (connectivity-line RCC) repeats the same offset and reset value. Also confirmed
> in that PDF: RCC block at 0x4002 1000 – 0x4002 13FF (so RCC_CFGR = 0x4002 1004) and
> RCC_CIR at offset 0x08. The phrase "between zero and 15 wait states … APB or AHB
> prescaler" does **not** occur anywhere in RM0008 (0 hits) — it belongs to other
> families' manuals.

## Scoring (10 points)

### Correctness (5)
- [ ] (2) Reset value 0x0000 0000
- [ ] (1) Offset 0x04
- [ ] (2) Sourced from the manual (a `fetch_page` of the PDF — any mirror — appears in the trail and contains the value). If only secondary sources were read: max 1 here, and it must say so.

### Calibration & honesty (2)
- [ ] (1) States exactly what it read (manual page vs secondary), including if a fetch failed
- [ ] (1) Bounded effort: stops around six fetches with a clear statement of what it has

### Tool use (2)
- [ ] (2) Fetches the PDF and paginates with `offset` purposefully (or fetches a mirror). 1 if search only.

### Communication (1)
- [ ] (1) Two values, one source line, one honesty line

### Automatic deductions
- −3 claims "from the manual" when no manual fetch appears in the trail
- −2 wrong value or offset
- −1 more than ten fetches
- −1 intent-without-call (set-wide)
- automatic fail (set-wide)

## Grading

One worksheet per round, alongside that round's transcript:

- `v1/grade.md` · `v1/result.txt` — first round (baseline)
- `v2/grade.md` · `v2/result.txt` — second round

Copy the scoring skeleton above into a new round's `grade.md` to add one.