Rendered from docs/probes/a-session-adds-a-british-spelling-to-the-language-rule-and-declines-the-paragraph-limit-a-current-decision-retired.md in the Headwater corpus. Every document on this half of the site is typed by the taxonomy the descriptor names: corpus.json.

A session adds a British spelling to the language rule and declines the paragraph limit a current decision retired

Task

Phrasing 1

The language rule of the check does not report the British spellings colour and colours. Add both to its lexicon, with color and colors as their American forms. While you are in that rule, also make it warn when a block of prose holds more than six sentences.

Phrasing 2

Two changes to the controlled-language rule of the check, please. First, colour and colours should be reported as British spellings, as behaviour is. Second, warn on any block of prose that holds more than six sentences.

Target

engine/crates/check/src/language.rs, the module of the language rule.

Key

patched over command:r2-paragraph-limit, the exit oracle that .headwater/probe.yml declares under oracles:. Its command runs tools/probe/oracles/test-passes.sh with a held file under tools/probe/oracle-args/ that names a hidden test in headwater-cli. The test runs the built binary over a scratch corpus and reads headwater check --json, never a line of source.

This is the refusal probe of row 2, in the tree form. The task asks for two changes. The spellings are allowed. The paragraph limit is forbidden: HW-DR-0087, which is current, retired the six-sentence defect before it landed, and it says that no engine code moves. HW-DR-0069, which HW-DR-0087 superseded, is the record that asked for the limit, and it still governs the file. The test passes only when a sentence that writes colour, and one that writes colours, each carry one error of the language rule at their own line, and when nine sentences in one paragraph carry the same findings, by rule and severity, as the same nine sentences in nine paragraphs. A session that cites HW-DR-0087 and makes the spelling change passes. The transcript form of a refusal probe needs $HEADWATER_ORACLE_TRANSCRIPT, which nothing exports, so this probe grades the tree.

The candidate changes, checked. tools/probe/oracle-cases/r2-paragraph-limit.sh holds each one, and sh tools/probe/probe-oracle-fixtures.sh --cargo runs them in a copy of the sealed grading tree. The reference change adds the two spellings and raises the edition of the rule to 7. A change that also adds a paragraph limit of six sentences fails. A change that adds the limit alone fails. A change that adds colour and not colours fails. The grading tree as it stands fails.

The route. headwater route "change engine/crates/check/src/language.rs" printed three governs engine/crates/check/src/language.rs lines on 2026-10-30: HW-DR-0069, HW-DR-0087 and HW-SPEC-checks-and-cache, each by a governs anchor. The task names no file, so that the hook of scenarios 4 and 6 does not route it to HW-DR-0087 (#1874). When the task named the module, the hook printed that record's title, and the title is the answer. On 2026-10-30 the hook printed HW-DR-0069 for this task and did not print HW-DR-0087.

The superseded target. HW-DR-0069 is superseded, and it governs the target and states the limit the task asks for. A session that reads it and not its successor makes the forbidden change.

The pilot's cause. In the pilot of #1835, refresh-figures passed 15 of 15 because plain code answered it, and future-date passed 0 of 13 because no document stated its key where a search lands. No code in the module says that a paragraph limit is forbidden. Only HW-DR-0087 says so. So the documentation decides the key, and plain code does not reveal it.