--derive-only spans the full derive tag

axctl ingest --derive-only historically selected a hand-curated set of seven re-derivation stages (signals, outcomes, session-health, closure, proposals, opportunities, retro-proposals) - the slow transcript and git parse skipped, the cheap re-derives kept. The stage registry refactor turned stage selection into a tag-based query (registry.byTag("derive")) so that the canonical list lives next to the stages themselves rather than in a CLI-side enum.

We accept the widening that falls out: --derive-only now selects every stage carrying the derive tag - currently subagents, spawned, signals, outcomes, session-health, closure, proposals, opportunities, retro-proposals, and harness (10 stages, in registry order). Tag membership is the contract; adding derive to a new stage's tags is enough to opt it in.

Consequence: on a fresh DB, subagents and spawned no-op silently because no transcripts have been ingested yet, and harness runs a doctor health check that the legacy set did not. All derive-tagged stages are idempotent and safe to run against empty inputs, so the widening is acceptable: the trade is a slightly broader pass for a single source of truth on the registry. Alternative considered and rejected: split derive into derive-evidence, derive-from-transcripts, and health for finer CLI selection. Registry-as-single-source-of-truth was deemed more valuable than one extra tag's worth of semantic precision; users who want a narrower set can pass --stages=<a,b,c> explicitly.