This is a non-shipping reference example. It lives outside the build (src/ → bin/lib/), the npm package files[], the installer, and the CI test suite (tests/). Nothing here is compiled into or installed with GSD. The production implementation lands in a later phase of the Dynamic Context Management epic (#1671).

What it demonstrates

The predicate fact-store → JIT selector slice of the platform: parse the repo-root CONTEXT.md CLASS.subkey=value predicates into structured records, drift-guard a generated index, and select the relevant predicate subset for a task — the building block for just-in-time agent-brief assembly instead of hand-citing a 200 KB file.

Files

context-predicates.cjs — parser + selector + deterministic index builder (self-contained).
gen-context-index.cjs — --check / --write drift-guarded generator + --select.
CONTEXT-INDEX.json — sample generated output (393 predicates, 18 classes).
demo.cjs — runnable usage example.

Run (from the repo root)

node examples/dynamic-context-management/demo.cjs
node examples/dynamic-context-management/gen-context-index.cjs --select PRED.k320
node examples/dynamic-context-management/gen-context-index.cjs --check

Validation

During research this slice was validated with 42 behavioral tests — predicate forms, fenced-code / prose skipping, duplicate-id detection, the selector, a deterministic index, and a fast-check property test. Those return as CI tests under tests/ when the production implementation lands.

It also surfaced 3 latent duplicate predicate IDs in CONTEXT.md (RULESET.WORKFLOW_MARKDOWN.FENCES, RULESET.GEMINI.TOOLS.ask_user, RULESET.GEMINI.TEST_SENTINEL), recorded in the index duplicates field.