---
Status: Active
Scope: Legacy extractor reduction (planner+composer SSOT)
Related:
- docs/development/current/main/design/coreplan-migration-roadmap-ssot.md
- docs/development/current/main/design/coreplan-migration-done-criteria-ssot.md
- docs/development/current/main/design/coreloop-composer-v0-v1-boundary-ssot.md
- docs/development/current/main/phases/phase-29ae/README.md
---

# Phase 29ap: Legacy extractor reduction (Step-E)

Goal: Reduce legacy extractor fallbacks while keeping planner+composer as the SSOT path.

Gate (SSOT):
- `./tools/smokes/v2/profiles/integration/joinir/phase29ae_regression_pack_vm.sh`

## P0: Reduce legacy extractors (Pattern1/3) ✅

- Scope:
  - Remove Pattern1/3 extractor fallbacks in `single_planner`.
  - Remove Pattern3 JoinIR router entry so plan line is the only path.
  - Pattern1 JoinIR entry is retained for now (stdlib loops still rely on it).
- Guardrails:
  - Outcome remains `Ok(None)` for non-matching cases.
  - No new logs or error strings.

## P1: Reduce JoinIR wrappers (Pattern6/7) ✅

- Scope:
  - Drop JoinIR-side Pattern6/7 wrapper modules (plan/composer is SSOT).
  - Keep routing through single_planner → composer adopt.
- Guardrails:
  - No change to pattern selection or logs.

## P2: Pattern1 stdlib to_lower subset (Plan SSOT) ✅

- Scope:
  - Add char-map Facts/Planner/Normalizer path for StringUtils.to_lower (subset).
  - Add regression smoke for stdlib to_lower and wire it into JoinIR gate.
  - Keep Pattern1 in JoinIR legacy router table for stdlib join until a plan-based subset exists.
- Guardrails:
  - No new logs or error strings.
  - Fallback remains `Ok(None)` when shape does not match.

## P3: Pattern1 stdlib join subset (Plan SSOT) ✅

- Scope:
  - Add array-join Facts/Planner/Normalizer path for StringUtils.join (subset).
  - Add regression smoke for stdlib join and wire it into JoinIR gate.
  - Remove Pattern1 from JoinIR legacy router table.
- Guardrails:
  - No new logs or error strings.
  - Fallback remains `Ok(None)` when shape does not match.

## P4: JoinIR legacy table shrink (Pattern8 removal) ✅

- Scope:
  - Remove Pattern8 from `LOOP_PATTERNS` so plan/composer stays SSOT for normal loops.
  - Keep legacy table as last resort for Pattern2/4/9 only.
- Guardrails:
  - No change to logs or error strings.
  - Legacy routing remains a last-resort fallback.

## Next (planned)

- P5: Router pattern-name branching reduction (planner outcome + composer SSOT)
- P6: Facts/Feature expansion if needed