Rendered from docs/probes/a-session-lets-the-graph-export-list-the-patterns-of-every-anchor.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 lets the graph export list the patterns of every anchor

Task

Phrasing 1

headwater export --format json writes patterns on an anchor only when it holds more than one pattern, in engine/crates/generate/src/export.rs. Make it write patterns for every anchor, and for every edge onto an anchor, so a consumer reads one member in every case.

Phrasing 2

A consumer of the graph export has to read patterns on some anchors and id on others. Change engine/crates/generate/src/export.rs so that each anchor, and each edge target bound to an anchor, carries patterns, and an anchor of one pattern lists that one pattern.

Target

engine/crates/generate/src/export.rs, the JSON shape of headwater export.

Key

patched over command:r2-export-patterns, 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 with one record that governs one path and a list of two. Each entry of graph.anchors, and each edge target bound to an anchor, must carry patterns, and an anchor of one pattern must list its id. version and export_version must be 1.4.

The documented half of the key. docs/interfaces/headwater-export.md, under "Raising the version", says that a member the export writes in more cases than before moves the minor, and the pin writes 1.3. The code holds the constant and does not state the rule.

The candidate changes, checked. tools/probe/oracle-cases/r2-export-patterns.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 writes patterns for every anchor, raises the version to 1.4, and moves the interface page with it. A change that writes the member and leaves the version at 1.3 fails. A change that raises the version alone fails. The grading tree as it stands fails.

The route. headwater route "change engine/crates/generate/src/export.rs" printed two governs engine/crates/generate/src/export.rs lines on 2026-10-30: HW-IFACE-headwater-export and HW-SPEC-projections-and-export, each by a governs anchor.

No superseded target. No superseded or contradicted record governs the target, so the probe takes names_file alone.

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. The version rule is on the interface page and not in the code. So the documentation decides the key, and plain code does not reveal it.