update_check: false makes gstack-update-check exit early and emit
nothing, but the preamble instruction text that tells the agent how to
act on UPGRADE_AVAILABLE / JUST_UPGRADED output still shipped in every
generated SKILL.md. The runtime layer honored the opt-out; the
instruction layer did not.
Follow the same echo-then-gate convention every other runtime flag uses
(PROACTIVE, SKILL_PREFIX, EXPLAIN_LEVEL, QUESTION_TUNING):
- generate-preamble-bash.ts reads update_check and echoes UPDATE_CHECK
so the instruction layer can see the value.
- generate-upgrade-check.ts gates the UPGRADE_AVAILABLE / JUST_UPGRADED
prose on UPDATE_CHECK == false.
The gstack-upgrade skill's own inline-flow documentation is unchanged:
a user in that skill is explicitly upgrading, so its prose is correctly
out of scope. All 49 preamble-bearing SKILL.md regenerated via
bun run gen:skill-docs.
Fixes#2001.
257e9e3ef5