Embedding-based semantic chunking (the strategy behind ingestion's NotImplementedError) — deferred until a deterministic-snapshot mode is designed #925

Deferred work · F-PR29-A6-05 · severity Low · cost the feature: not estimated · recorded in docs/roadmap/risks-and-decisions.md:98

Summary

forgelm/ingestion.py reserves a semantic chunking strategy that raises NotImplementedError, and its message points users at a roadmap table row instead of an issue. The work was deferred at Phase 12 because a runtime embedding-model dependency and non-deterministic chunk counts conflict with air-gapped, reproducible Annex IV evidence. This issue is the tracker the error message should link to.

Condition or budget

Only viable once a deterministic-snapshot mode is designed (Phase 12's won't-do list in completed-phases.md).

State today (re-checked 2026-10-09)

_chunk_semantic raises NotImplementedError; no issue tracked the feature before this one.

Related

#712 asks for a real issue URL in the NotImplementedError message — this issue; #837 suggested pointing at the roadmap row instead.

Acceptance criteria

• The NotImplementedError message links this issue (through [Wave 4] Low/info — Module sweep: Training orchestration, multi-stage pipelines, resume & no-train modes (part 1/3) #712).
• When the condition holds: a deterministic, air-gap-safe semantic chunker with a pinned embedding snapshot and reproducible chunk counts.
• The row is removed from the deferral table and the CHANGELOG names its ID (the table's removal contract).

_{Recorded in docs/roadmap/risks-and-decisions.md (read at f94595f) and re-checked against the code on 2026-10-09. The row leaves that table only when the fix is on main, the CHANGELOG names its ID and any promised guard exists.}