> **Implementation note (scope narrowed from the original proposal).** This RFC proposed pruning dead methods from BOTH the persistence seam (`SessionPersistence.has()`/`.delete()`) and the bash seam (`BashExecutor.get()`/`.list()`). Only the **persistence** removal shipped. The bash `get()`/`.list()` removal was reverted before merge: each is a one-line accessor over the executor's already-tracked `tasks` map, and removing them forced `dsh-tool-bash`'s tests onto a ~35-line `onTaskDone`-based completion-tracking harness to replace the one-line `ctx.bash.get(id)` lookup — the migration cost dwarfed the surface removed. Per the [AGENTS.md "RFCs are proposals, not golden truth"](../../../../AGENTS.md) principle, that friction is evidence the method earns its keep (a test harness IS a consumer that programs against the seam), so `get()`/`list()` stay. The bash-seam analysis below is retained for the record but was NOT acted on; `BashTaskId`-branding those methods lands in the [branded-ids RFC](../architecture/2026-06-20-branded-ids.md) instead. The persistence removal stands: `has()`/`delete()` had only contract-test callers and no test-ergonomics cost to remove.
A capability seam ([interface / implementation / consumer](../../implemented/architecture/2026-06-13-capability-seams.md)) carries abstract methods that no consumer calls. The seam exists to let implementations and consumers evolve independently — but a method no consumer programs against is not a seam, it is speculative surface every implementation must still implement and test.
The abstract service declared its operations beyond create/append: `load`, `list`, `has`, `delete`. Production consumers of `ctx.sessionPersistence` use only two: the agent-loop resume path calls `load()` ([packages/core/agent-loop/src/index.ts:176](../../../../packages/core/agent-loop/src/index.ts)), and the ACP bridge calls `list()` for `session/list` ([packages/ui/acp/src/index.ts:494](../../../../packages/ui/acp/src/index.ts)). Grepping every `sessionPersistence.*` / `persistence.*` use across `packages/*/src` and `examples/` finds no `has(` and no `delete(` on the service. The `.has(`/`.delete(` calls in `packages/ui/acp/src/index.ts` are on the in-memory `SessionStore` and a local `Set` of loading ids, not persistence. The only callers of `has`/`delete` were the contract suites and per-backend specs.
`has()` was not just unused — it was the most intricate branch in the shared coordinator: a tracked-vs-untracked dual-probe (`loadLive(id, cwd)` for a live-tracked session vs `loadStored(id)` for an untracked one) with a multi-line rationale. `delete()` dragged the `deleteStored` backend hook that every backend had to implement. This is the [drop-mutable-session-summary](../../implemented/simplification/2026-06-19-drop-mutable-session-summary.md) pattern: a contract test exercised both, but no shipping code asks "is this session persisted?" or removes one.
-`SessionPersistence.has()` / `.delete()`: delete the abstract declarations, the coordinator's `has`/`delete`/`deleteCore`, and the `PersistenceBackend.deleteStored` hook. Remove the `has`/`delete` rows from the contract suite and the per-backend specs (jsonl + sqlite each implemented `deleteStored` only to satisfy the hook — that implementation goes too). The backends are the [dual-backend](../../implemented/architecture/2026-06-14-session-persistence.md) design and otherwise out of scope, but removing a hook they implement for no consumer is part of removing the hook, not a backend redesign.
- Update every doc and source-comment reference to the removed methods — not only literal `has(`/`delete(`/`deleteStored` call spellings, but also `{@link has}`/`{@link delete}` JSDoc links and prose that counts the methods (removing 2 of the persistence service's 6 public methods makes any "six public methods" phrasing wrong). The implementing PR greps `has`/`delete`/`deleteStored`/`{@link `/`six ` across `docs/`, `packages/*/README.md`, and source comments, and fixes each. The known doc sites: the seam README ([packages/session-persistence/session-persistence/README.md](../../../../packages/session-persistence/session-persistence/README.md)'s `has(id)`/`delete(id)` API row and its "delegates its six public service methods" prose → four), the backend READMEs that describe `has`/`list` semantics ([packages/session-persistence/session-persistence-sqlite/README.md](../../../../packages/session-persistence/session-persistence-sqlite/README.md), [packages/session-persistence/session-persistence-jsonl/README.md](../../../../packages/session-persistence/session-persistence-jsonl/README.md) — reword "absent from `has()`/`list()`" to just `list()`), the service-map / seam docs in [docs/architecture.md](../../../architecture.md), and the persistence prose in the [session-persistence RFC](../../implemented/architecture/2026-06-14-session-persistence.md) and [shared write-coordinator RFC](../../implemented/architecture/2026-06-18-shared-persistence-write-coordinator.md). The known source-comment sites: the abstract `create()` JSDoc's `{@link has}/{@link list}` link ([packages/session-persistence/session-persistence/src/index.ts](../../../../packages/session-persistence/session-persistence/src/index.ts) — drop the `has` link), the coordinator's "six public methods"/"six public service methods" module + class JSDoc and its lazy-materialization JSDoc justifying the `materialized` flag by "the signal `has`/`list` rely on" ([packages/session-persistence/session-persistence/src/coordinator.ts](../../../../packages/session-persistence/session-persistence/src/coordinator.ts)), the JSONL backend's `loadStored`/`deleteStored` comment, and the SQLite backend's `schema.ts` and `index.ts` comments that mention "absent from `has`/`list`" — all reworded to the surviving four-method, `list()`-only contract.
The instinct that a persistence seam "should" offer delete is real — and it is exactly the speculative-completeness the pre-release stance warns against ([AGENTS.md](../../../../AGENTS.md): optimize for the correct foundation, not for hypothetical callers you do not have). `delete()` is one method to re-add the day a consumer needs it: a session-management UI that deletes old sessions will want it — add it then, designed against that UI's real needs (soft-delete? cascade? confirmation?), not guessed now.
Re-adding a seam method with a live consumer is cheap and better-designed than the speculative version, because the consumer pins the contract. Carrying it unused means every implementation (and every future backend) must implement and test a method that does nothing.
- **`delete()` is the kind of operation a product eventually wants.** True — but "eventually" is the point. Deleting it now and re-adding it against a real consumer is strictly better than shipping a guessed contract. The dual backends each shed a `deleteStored` impl, which is a bounded edit in otherwise-out-of-scope packages.
- **Low coupling.** The removal is confined to the persistence seam + impl + tests; no cross-package consumer references the removed methods, so there is no ripple beyond the docs.
