# Plan: ADR-0035 Phase 4, sub-phase 4h — `ALTER TABLE … RENAME TO`

Add the advanced-mode SQL form:

- `ALTER TABLE <old> RENAME TO <new>` — rename a table. **Advanced-mode
  only** (no simple-mode rename-table verb; ADR-0035 §6). Closes the
  rename half of `C1` for the advanced surface.

This is the **one genuinely new low-level op** in Phase 4 (ADR-0035 §6) —
not a reuse of an existing executor. Within one transaction it renames
the table in the database, renames its `data/<old>.csv` → `data/<new>.csv`
(via the persistence layer), and updates **every** metadata row that
names it.

**User-confirmed scope (2026-05-26):**
- **Same-name rename** (`rename T to T`) → **refuse** with a friendly
  error (mirrors the existing `rename column` identical-rename refusal).
- **CHECK-text drift → rewrite the stored CHECK text** (the §7 DA
  finding). The engine rewrites table-qualified column references inside
  the renamed table's own CHECKs in the *live* schema (`CHECK (T.age>0)`
  → `CHECK ("U".age>0)` — confirmed empirically on SQLite 3.48). Our
  *stored* CHECK text (both `__rdbms_playground_columns.check_expr` and
  `__rdbms_playground_table_checks.check_expr`) must be rewritten the same
  way, or a fresh rebuild emits `CHECK (T.age>0)` for a table now named
  `U` and fails. **Bounded problem:** a CHECK constraint may reference
  only the table's own columns (SQLite forbids subqueries / other tables
  in CHECK), so the *only* table qualifier that can appear is the old
  table name — the rewrite target is unambiguous (`old`/`"old"` → `new`/
  `"new"`). Reuses/extends the 4e CHECK tokenizer (`check_references_
  column`, `db.rs:5489`) which already skips string literals and is
  case-insensitive.
- **Auto-named labels (indexes *and* relationships) → left stale** on
  rename. ADR-0035 §6 lists only CSV + column/relationship/table-CHECK
  metadata to update; auto-named indexes (`<table>_<cols>_idx`) and
  auto-named relationships (`{parent}_{pcol}_to_{child}_{ccol}`,
  `db.rs:5982`) keep their old names — functional, just cosmetically
  referencing the old table name. **Documented caveat:** index names are
  schema-global and relationship names are `UNIQUE`, so recreating a
  table under the *old* name later could collide with a stale label;
  this is an accepted consequence (cosmetic refresh is a possible
  4i/follow-up, out of 4h).

**Decided-and-noted (conventional defaults, no user fork):**
- **Rename to an existing *other* table** → **refuse** "table `<new>`
  already exists" (an explicit, engine-neutral pre-check before the
  native rename, which would otherwise surface engine wording).
- **Rename of an FK parent or child** → **allowed** (unlike DROP, which
  refuses inbound FKs). The native rename rewrites child FK references in
  the live schema; we update both ends of the relationship metadata.
- **Success feedback** → **auto-show the renamed table** under its new
  name (returns a `TableDescription`, mirroring `rename column`).
- **Target name** → parse-time `reject_internal_table` validator on the
  new-name slot (mirrors the `CREATE TABLE` name slot) + executor
  `reject_internal_table_name` guard for defense in depth.

## 1. Baseline (at handoff 40)

- After 4g + the rebuild fix: **1885 passing, 0 failed, 0 skipped, 1
  ignored** (the `friendly/mod.rs` ` ```ignore ` doctest); clippy clean
  (`cargo clippy --all-targets -- -D warnings`). Branch `main`, HEAD
  `6112859` (the handoff-40 docs commit; `6ff97f6`/`50a889e`/`6112859`
  are local-only — normal). Re-verified this session: **1885 / 0 / 0 /
  1**.

## 2. Decisions (settled)

1. **One new low-level executor, `do_rename_table`.** No existing reuse
   (§6 is explicit: rename is a genuinely new op). It uses the engine's
   native `ALTER TABLE <old> RENAME TO <new>` (structure-preserving — no
   rebuild needed), then updates the three `__rdbms_*` metadata tables,
   then drives persistence, then commits the db last (ADR-0015 §6
   ordering). Mirrors the shape of `do_rename_column` (`src/db.rs:4314`).

2. **CSV rename reuses the existing persistence machinery — no new
   method.** `finalize_persistence` (`src/db.rs:2663`) already (a) on
   `schema_dirty` rewrites the *entire* `project.yaml` from the live db
   schema — so the rename is reflected automatically — and (b) writes a
   CSV per `rewritten_tables` entry (read in-tx by name) and deletes a
   CSV per `deleted_tables` entry. So:
   ```rust
   Changes { schema_dirty: true,
             rewritten_tables: vec![new.to_string()],   // writes data/<new>.csv
             deleted_tables:   vec![old.to_string()] }  // removes data/<old>.csv
   ```
   The renamed table is read by its new name (visible in-tx after the
   native rename), serialised to `data/<new>.csv`, and `data/<old>.csv`
   is deleted. Empty tables produce no CSV on either side (the existing
   `write_table_data` empty-→-delete rule), preserving the ADR-0015
   "empty tables → no CSV" invariant. NULL-vs-empty fidelity is preserved
   because the rows are re-serialised from the db (where NULL is NULL),
   not byte-copied. **No `rename_table_data` method, no `Changes` field
   added.** (The Explore-suggested "add a file-rename method" is rejected
   in §5 R-alt.)

3. **Metadata updates — all three tables, both relationship ends, plus
   CHECK-text reconciliation.** Within the tx, after the native rename:
   - `__rdbms_playground_columns` (`META_TABLE`): `table_name old→new`;
     **and** rewrite any column-level `check_expr` whose text qualifies a
     reference with the old table name (`old.`/`"old".` → `new.`/`"new".`
     — §2.9).
   - `__rdbms_playground_relationships` (`REL_TABLE`): `parent_table
     old→new` **and** `child_table old→new` (two UPDATEs — covers a table
     that is an FK parent, a child, or **self-referential** at once). The
     relationship `name` is **not** touched (left stale per the user
     decision; FK endpoints are stored as table-name *values*, not as
     expression text, so they need no rewrite — only the column UPDATE).
   - `__rdbms_playground_table_checks` (`CHECK_TABLE`): `table_name
     old→new`; **and** rewrite each table-level `check_expr` the same way
     (§2.9).
   No index metadata table exists (indexes are PRAGMA-derived with a
   `unique` flag; ADR-0025 Amd 1), so nothing to update there — indexes
   follow the renamed table natively and keep their (stale) names per the
   user decision. DEFAULT expressions do **not** drift (SQLite defaults
   cannot reference the table).

4. **Grammar — split the `rename` verb into an inner Choice** (the §6.1
   "no same-leading-keyword Choice siblings" rule). Today `AT_RENAME_COLUMN`
   is the lone `rename`-led branch in `AT_ACTION_CHOICES`. Replace it with
   one `AT_RENAME` branch (`rename` + an inner `Choice`) whose two tails
   lead on **distinct** second keywords: `column` (→ rename column) and
   `to` (→ rename table). Mirrors the 4g `add`/`drop` restructure.

5. **New-name ident slot is distinct from the target slot.** The table
   being altered binds role `table_name` (`AT_TABLE_NAME`,
   `IdentSource::Tables`). The rename target binds a **new** role
   `new_table_name` (`IdentSource::NewName`, `validator:
   Some(reject_internal_table)`, all `writes_*: false`, wrapped in
   `NEW_NAME_HINT`) — mirrors the `CREATE TABLE` name slot for parse-time
   `__rdbms_*` refusal and the `NEW_COLUMN_NAME` hint treatment. Distinct
   roles keep `require_ident(path, "new_table_name")` unambiguous.

6. **Builder discrimination** (`build_sql_alter_table`, `ddl.rs:2131`):
   insert a `rename` branch **before** the final `else` (DropConstraint).
   Order becomes `type` → `column` → `add` → **`rename`** → else `drop`.
   By the time control reaches the `rename` check, `column` is absent
   (caught earlier), so `rename` present ⇒ table rename:
   `AlterTableAction::RenameTable { new: require_ident(path,
   "new_table_name")? }`.

7. **One undo step.** `do_rename_table` is one user mutation carrying a
   `source`, snapshotted by the worker `snapshot_then` hook (whole-project
   snapshot — db backup + yaml/csv copy), so a rename is exactly one
   `undo` step. Same wiring as every other `SqlAlterTable` action.

8. **Replay / history.** `finalize_persistence` appends the literal SQL
   line to `history.log`; `alter` is a schema-write entry word (not in the
   ADR-0034 Amd 1 app-lifecycle skip set), so the rename replays as a
   write with no replay-filter change.

9. **CHECK-text qualifier rewrite (§7 DA Finding 1).** A new helper
   `rewrite_check_table_qualifier(check_expr, old, new) -> String`
   rewrites every occurrence of the old table name **used as a qualifier**
   (immediately followed by `.`), in both the bare (`old.`) and quoted
   (`"old".`) forms, case-insensitively, **skipping string literals** —
   extending the 4e tokenizer that `check_references_column` already uses.
   A bare token equal to the old name but *not* followed by `.` (e.g. a
   column literally named like the table) is left untouched, so the
   common unqualified CHECK (`age > 0`) is a no-op. Applied in
   `do_rename_table` to every column-level `check_expr` (META) and every
   table-level `check_expr` (CHECK_TABLE) of the renamed table. Re-enters
   in advanced mode (ADR-0030 §11) — the rewritten text is still valid SQL
   the user could retype.

10. **Existence check is explicit (§7 DA Finding 2).** `read_schema` does
    **not** error on a missing table (`pragma_table_info` returns zero
    rows). The "no such table" guard uses an explicit
    `do_list_tables(conn)?.iter().any(|t| t == old)` check, not a reliance
    on `read_schema` failing.

## 3. Phase 1 — Requirements checklist (4h)

### Grammar / dispatch
- [ ] `AlterTableAction` gains `RenameTable { new: String }`.
- [ ] `NEW_TABLE_NAME` ident node (role `new_table_name`,
  `IdentSource::NewName`, `reject_internal_table` validator, `NEW_NAME_HINT`).
- [ ] `AT_RENAME` = `Seq[rename, Choice[AT_RENAME_COLUMN_TAIL,
  AT_RENAME_TABLE_TAIL]]`; the two tails lead on distinct keywords
  (`column` / `to`). `AT_RENAME_COLUMN_TAIL` = `column <old> to <new>`;
  `AT_RENAME_TABLE_TAIL` = `to <new>`. `AT_ACTION_CHOICES` swaps
  `AT_RENAME_COLUMN` → `AT_RENAME`.
- [ ] `build_sql_alter_table` routes `rename` (no `column`) → `RenameTable`.
- [ ] Existing four action branches still route (add/drop/rename/alter
  column, alter-column-type, add/drop constraint); trailing `;` tolerated;
  `alter` stays advanced-only; source table slot rejects `__rdbms_*` at
  parse (existing `AT_TABLE_NAME` validator); target slot rejects
  `__rdbms_*` at parse (new validator).

### Execution
- [ ] `do_rename_table(conn, persistence, source, old, new)`:
  `reject_internal_table_name(old)` + `(new)`; **existence** — explicit
  `do_list_tables` contains `old` (→ friendly "no such table", *not* a
  reliance on `read_schema` erroring — §2.10); **same-name** (`old==new`)
  → friendly refusal; **existing-target** (`do_list_tables` contains
  `new`) → friendly "already exists" refusal (pre-empts the engine's own
  collision wording); tx: native `ALTER TABLE … RENAME TO` + the metadata
  UPDATEs (§2.3) **+ the CHECK-text rewrite** (§2.9, both META and
  CHECK_TABLE `check_expr`); `do_describe_table(conn, new)` for auto-show;
  `finalize_persistence` with the §2.2 `Changes`; `tx.commit()`.
- [ ] `rewrite_check_table_qualifier` helper (§2.9) + its own unit tests
  (bare `T.age`→`U.age`; quoted `"T".age`→`"U".age`; case-insensitive;
  string literal `'T.x'` untouched; bare column named `T` untouched;
  unqualified `age > 0` unchanged).
- [ ] Worker `Request::RenameTable { name, new, source, reply }`;
  `Database::rename_table(table, new, source)` method; handler arm wrapped
  in `snapshot_then` (one undo step).
- [ ] `runtime.rs` `SqlAlterTable` match: `RenameTable { new }` →
  `database.rename_table(table, new, src)` mapped like the `RenameColumn`
  arm.
- [ ] `app.rs` `build_translate_context`: `RenameTable { .. }` →
  `(Operation::RenameTable, Some(table), None)`.
- [ ] `Operation::RenameTable` added; `keyword()` arm → `"rename table"`.

### Testing
- [ ] **Tier 1** (`sql_alter_table_tests` in `ddl.rs`): parse `alter table
  T rename to U` → `RenameTable { new: "U" }`; `alter table T rename
  column a to b` still → `RenameColumn`; the other four actions still
  route; target `__rdbms_*` refused at parse.
- [ ] **Tier 3** (`tests/sql_alter_table.rs` via `run_replay`):
  - rename a table **with rows** → the CSV follows (`data/<new>.csv`
    present, `data/<old>.csv` gone), data intact incl. a NULL.
  - rename an **FK parent** → relationship metadata `parent_table`
    updates; the child's FK still enforces (a violating child insert is
    rejected under the new name).
  - rename an **FK child** → `child_table` updates; FK still enforces.
  - rename a **self-referential** table → both ends update, no PK
    conflict on `REL_TABLE`.
  - rename a table with a **table-level CHECK** → `table_checks` rows
    follow; the CHECK still enforces.
  - rename a table with a **table-qualified CHECK** (both a column-level
    `CHECK (T.age > 0)` and a table-level `CHECK (T.a <> T.b)`) → the
    stored `check_expr` is rewritten to the new name, the CHECK still
    enforces, **and the project survives a fresh rebuild** (the precise
    §7 Finding-1 regression — without the rewrite, rebuild fails with "no
    such table T").
  - rename a table with an **index** → index still present + functional
    (name unchanged, per the user decision).
  - **survives a fresh rebuild** — delete the `.db`, `rebuild` from
    `project.yaml`/CSV: the renamed table + all its metadata round-trip
    (the §6.4 fresh-rebuild discipline).
  - **one undo step**: rename, `undo`, the table is back under its old
    name with its rows/relationship/CHECK; `redo` reapplies.
  - **refusals**: rename to an existing other table; rename to the same
    name; rename to an `__rdbms_*` name (executor guard, in case the
    parse validator is bypassed by a synthesised command); rename a
    non-existent table.
- [ ] **Catalog** lockstep + vocab audit for the refreshed
  `sql_alter_table` usage (now listing `rename to <NewName>`); the wording
  stays engine-neutral.

## 4. Architecture & change list (file by file)

- **`src/dsl/command.rs`**: `AlterTableAction::RenameTable { new: String }`.
- **`src/dsl/grammar/ddl.rs`**:
  - `NEW_TABLE_NAME_IDENT` / `NEW_TABLE_NAME` nodes (≈ near
    `AT_RENAME_COLUMN`, mirroring `NEW_COLUMN_NAME` at line 501 + the
    `CREATE TABLE` name slot's `reject_internal_table` validator).
  - `AT_RENAME_COLUMN_TAIL` (the existing `column …` body minus the
    leading `rename`), `AT_RENAME_TABLE_TAIL` (`to <new>`),
    `AT_RENAME_TAIL` (`Choice`), `AT_RENAME` (`Seq[rename, tail]`); swap
    into `AT_ACTION_CHOICES` (line 1998).
  - `build_sql_alter_table` (line 2131): the `rename` branch + doc-comment
    update (discrimination now `type → column → add → rename → drop`).
- **`src/db.rs`**:
  - `Request::RenameTable` variant (the worker request enum, ≈452–650).
  - `Database::rename_table` method (mirror `rename_column`).
  - handler dispatch arm (≈ the `RenameColumn` arm) wrapped in
    `snapshot_then`.
  - `do_rename_table` executor (model: `do_rename_column` at 4314 +
    `do_drop_table` at 3227 for the persistence-cleanup shape). Uses an
    explicit `do_list_tables` existence/collision check (§2.10), not
    `read_schema`-erroring.
  - `rewrite_check_table_qualifier` helper near the 4e CHECK tokenizer
    (`check_references_column`, `db.rs:5489`); applied in
    `do_rename_table` to META + CHECK_TABLE `check_expr` (§2.9).
- **`src/runtime.rs`**: `SqlAlterTable` inner match → `RenameTable` arm.
- **`src/app.rs`**: `build_translate_context` inner match → `RenameTable`
  arm (≈1595).
- **`src/friendly/translate.rs`**: `Operation::RenameTable` + `keyword()`
  arm `"rename table"`.
- **`src/friendly/strings/en-US.yaml`**: add the `rename to <NewName>`
  line to the `sql_alter_table` usage; any new refusal-message keys
  (same-name / existing-target) — engine-neutral, vocab-audit-clean.
  (`parse.usage.sql_alter_table` / `help.ddl.sql_alter_table` keys already
  registered in `keys.rs`.)

## 5. Phase 2 — Candidate approaches (key forks)

**Rename mechanism.** (M1) the engine's native `ALTER TABLE … RENAME TO`
+ manual metadata UPDATEs *(lead — structure-preserving, atomic, no data
movement; the engine also rewrites child FK references in the live schema
since `legacy_alter_table` is off by default)*. (M2) the ADR-0013
rebuild-table primitive (create new, copy rows, drop old) — *rejected*
(heavyweight; rebuilds the whole table to change only its name; rename is
not a structural change). (M3) drop + recreate — *rejected* (loses rows;
absurd for a rename).

**CSV persistence.** (R1) reuse `finalize_persistence` with
`rewritten_tables=[new]` + `deleted_tables=[old]` *(lead — zero new
machinery; re-serialises by the new name, deletes the old, handles
empty-table-no-CSV for free)*. (R-alt) add a `Persistence::rename_table_data`
+ a `Changes.renamed_tables` field and `fs::rename` the file —
*rejected* (new public method + new struct field for behaviour the
existing rewrite+delete path already delivers; byte-copy buys nothing over
re-serialisation since rows come from the db). (R3) leave the CSV under
the old name and special-case the loader — *rejected* (breaks the
`data/<table>.csv` invariant; confuses a human reading the project dir).

**Grammar.** (G1) split `rename` into one branch with an inner `Choice`
on the distinct second keyword (`column` / `to`) *(lead — the established
§6.1 + 4g pattern; trap-safe)*. (G2) two sibling `rename`-led branches in
`AT_ACTION_CHOICES` — *rejected* (the walker `Choice` does not backtrack
between same-leading-keyword branches; this is exactly the 4g trap). (G3)
make the `column` keyword optional and disambiguate purely in the builder
— *rejected* (ambiguous grammar; the optional-keyword shape invites the
same backtracking trap and muddies completion).

**Target `__rdbms_*` refusal.** (V1) parse-time validator on the
new-name slot (mirrors `CREATE TABLE`) **and** an executor guard *(lead —
earliest feedback + defense in depth; the worker is directly reachable by
synthesised commands/tests)*. (V2) executor guard only — *weaker* (loses
the pre-submit `[ERR]` indicator the CREATE name slot gives). (V3)
parse-only — *rejected* (a synthesised `RenameTable` command would slip a
metadata-table rename past the guard).

## 6. Phase 3 — Selection

**M1 + R1 + G1 + V1.** Satisfies every §3 item with the smallest faithful
change: native rename is the one new low-level op §6 calls for; the CSV
rename rides the existing rewrite+delete path (no new persistence surface);
the grammar mirrors the trap-safe 4g restructure; the target gets the same
parse-time `__rdbms_*` refusal as `CREATE TABLE` plus an executor guard.
The same-name and existing-target refusals (user-confirmed / conventional)
keep the surface honest; auto-named index *and* relationship names are
left as-is per the ADR §6 scope and the user decision; and the CHECK-text
rewrite (§2.9) keeps the stored metadata in step with the live schema so
a fresh rebuild round-trips.

## 7. Devil's Advocate review of this plan

**Planning `/runda` pass (2026-05-26) — three findings, all resolved:**

- **Finding 1 (BLOCKING, resolved → rewrite).** CHECK-expression text
  drift: empirically confirmed that SQLite (3.48, `legacy_alter_table`
  off) rewrites a table-qualified column reference in the renamed table's
  *live* CHECK (`T.age`→`"U".age`), while the *stored* `check_expr` would
  stay `T.age` and break a fresh rebuild. The original plan was silent on
  it. **Resolved** by §2.9 (rewrite the stored CHECK text in both
  metadata tables), user-confirmed; bounded because a CHECK can only
  reference its own table; regression test added (§3). This is the exact
  class as the `50a889e` rebuild-metadata bug and the 4e column-CHECK
  drift — the `/runda` "probe, don't reason" pass earned its keep again.
- **Finding 2 (correction, resolved).** `read_schema` does not error on a
  missing table; the existence/“no such table” guard is now an explicit
  `do_list_tables` check (§2.10).
- **Finding 3 (consistency, resolved → leave stale).** Auto-named
  relationships embed the table name (`db.rs:5982`) exactly like auto-
  named indexes; both are left stale on rename per the user decision,
  with the UNIQUE/global-name collision caveat documented.

- **Forks escalated?** All four genuine forks (same-name behaviour;
  auto-named-label handling; CHECK-text drift; relationship-vs-index
  consistency) were put to the user (2026-05-26) and answered. The
  conventional edges (existing-target refuse; FK-parent/child allowed;
  auto-show; target-name validation) are decided-and-noted with
  rationale, inviting correction. No silent autonomous design call. ✓
- **Grammar trap (the recurring 4g bite)?** The two `rename` tails lead
  on **distinct** keywords (`column` vs `to`) under one `rename` branch —
  exactly the §6.1 rule. A parse test for both tails + the four other
  actions guards it. ✓
- **New-name role collision?** The target binds a *distinct* role
  (`new_table_name`), so `require_ident` cannot confuse it with the
  `table_name` target slot. ✓
- **Fresh-rebuild metadata loss (the `50a889e` class)?** 4h changes
  metadata *values* (renames), not the schema — `do_rebuild_from_text`
  already wipes + repopulates META/REL/CHECK from yaml, and the yaml is
  rewritten under the new name by `schema_dirty`. A fresh-rebuild test is
  mandatory (§3) and is the precise probe for this class. ✓
- **Both relationship ends + self-ref?** Two UPDATEs (`parent_table`,
  `child_table`); a self-referential table updates both with no
  `REL_TABLE` PK `(child_table, child_column)` conflict (single row,
  `new` was not previously a child_table). Explicit self-ref test. ✓
- **CSV fidelity (NULL vs empty, empty tables)?** Re-serialised from the
  db, not byte-copied — NULL stays NULL; an empty renamed table writes no
  `<new>.csv` and deletes `<old>.csv` (the existing empty-→-delete rule).
  Test renames a table with a NULL cell. ✓
- **FK enforcement after rename?** `legacy_alter_table` is off, so the
  native rename rewrites child FK references in the live schema; the
  metadata UPDATE keeps `REL_TABLE` consistent; rebuild regenerates FK
  DDL from the updated metadata. Tests assert enforcement under the new
  name + a rebuild round-trip. ✓
- **Engine neutrality?** The same-name / existing-target refusals are
  authored engine-neutral ("table", "the database"); the native rename's
  own collision error is pre-empted by the explicit `do_list_tables`
  check so the engine wording never surfaces. Vocab audit + catalog
  lockstep guard it. ✓
- **One undo step?** One executor call = one `snapshot_then` = one
  whole-project snapshot. e2e undo/redo test. ✓
- **Anything dropped?** Auto-named index refresh (out of scope, user
  decision, noted as a possible 4i/follow-up). No silent drops.

## 8. Implementation sequence (test-first)

1. **Command + Operation + grammar + builder.** Add `RenameTable`
   variant, `Operation::RenameTable`, the `NEW_TABLE_NAME` node + the
   `AT_RENAME` split, the builder branch. Tier-1 parse tests
   (rename-table vs rename-column dispatch; the four other actions;
   target `__rdbms_*` refusal) → red, then exhaustive arms (compiler
   finds `runtime.rs` / `app.rs` / `keyword()`) → green (parse only).
2. **CHECK-text rewrite helper.** `rewrite_check_table_qualifier` (§2.9)
   with unit tests first (bare/quoted/case/string-literal/bare-column/
   unqualified) → red → green. Isolated, lands before the executor uses
   it.
3. **Executor + worker wiring.** `do_rename_table` (explicit existence
   check; metadata UPDATEs; the CHECK-text rewrite over META + CHECK_TABLE),
   `Request::RenameTable`, `Database::rename_table`, the `snapshot_then`
   handler arm, the `runtime.rs` + `app.rs` arms. Tier-3 e2e (rows/CSV, FK
   parent, FK child, self-ref, table-CHECK, **table-qualified CHECK +
   fresh rebuild** (the Finding-1 regression), index, fresh rebuild,
   undo/redo, all four refusals) → red where they exercise new behaviour,
   then green.
4. **Catalog + docs.** Refresh `sql_alter_table` usage (`rename to`);
   add refusal-message keys; ADR-0035 Status + §13 4h; README;
   `requirements.md` `Q1`/`C1` — all lockstep.
5. **Full sweep.** `cargo test` (no regression from 1885) + `cargo
   clippy --all-targets -- -D warnings`.
6. **Finished-slice `/runda`** (per handoff §7 — budget at least one,
   covering 4h; it found the rebuild bug last session). Fix anything it
   surfaces, re-green.
7. **Commit proposal** — propose the message, wait for approval. No AI
   attribution. (Push is the user's step.)

## 9. Exit gate

- All §3 items satisfied; all tiers green, zero skips; no regression from
  1885; written-DA / `/runda` PASS; clippy clean; ADR-0035 §13 4h + README
  + `requirements.md` lockstep. After 4h, only **4i** (the verification
  sweep) remains to complete Phase 4.
