Roadmap: causal rope everywhere and only causal rope #255

Target

All product text truth in Jim flows through graph-backed causal rope authority. Full strings may exist only as imports, exports, render windows, tests, or caches. They must never be authority.

Definition of done

• Every buffer has a BufferWorldline and current RopeHead.
• Every edit is an admitted causal ReplaceRange producing rope rewrite/diff/tick evidence unless it is a logical no-op.
• Standard undo and redo are forward causal intents derived from Echo-retained receipts and survive process restart.
• Every save/export creates Echo/Jim anchor or checkpoint evidence without mutating text authority.
• Every product read names basisHeadId and byteRange.
• Gutter, footer, dirty state, and :why are backed by rope facts rather than Git or snapshots.
• Full-snapshot fixture authority is test-only and import-banned from product code.

Goalposts and slices

CR-00 - Seal snapshot escape hatches

Goalpost: make the full-snapshot runtime visibly test-only and prevent product code from using any non-causal text authority.

• Slice: Inventory every product text authority path #216 Slice: Inventory every product text authority path
• Slice: Ban full-snapshot fixture imports from product code #217 Slice: Ban full-snapshot fixture imports from product code
• Slice: Fail installed product construction without graph rope authority #218 Slice: Fail installed product construction without graph rope authority

CR-01 - Echo CausalAnchor integration

Goalpost: use application-requested, Echo-admitted causal anchors as the generic durability primitive behind Jim rope checkpoints.

• Slice: Define Jim-to-Echo CausalAnchor API boundary #219 Slice: Define Jim-to-Echo CausalAnchor API boundary
• Slice: Separate rope checkpoints from Echo anchor admission #220 Slice: Replace Jim-local anchor shim with Echo-admitted anchors
• Slice: Add checkpoint materialization boundary witnesses #221 Slice: Add anchor retention and materialization metadata witnesses

CR-02 - Installed graph rope authority

Goalpost: make installed Jim create, read, replace, and checkpoint through graph-backed rope authority by default.

• Design graph-backed rope runtime authority #206 Design graph-backed rope runtime authority
• Slice: Install graph rope runtime as Jim default text authority #222 Slice: Install graph rope runtime as Jim default text authority
• Slice: Import file bytes into BufferWorldline and initial RopeHead #223 Slice: Import file bytes into BufferWorldline and initial RopeHead
• Slice: Route normal editor edits through replaceRangeAsTick #224 Slice: Route normal editor edits through replaceRangeAsTick
• Slice: Route standard undo and redo through Echo causal history #273 Slice: Route standard undo and redo through Echo causal history
• Slice: Render source text through basis textWindow reads #225 Slice: Render source text through basis textWindow reads
• Slice: Save and export from current RopeHead through causal checkpoint evidence #226 Slice: Save and export from current RopeHead through causal checkpoint evidence

CR-03 - Coordinates and materialization discipline

Goalpost: make UTF-8 byte ranges authoritative and require every materialized string to name its rope head and byte range basis.

• Slice: Add branded coordinate adapters for UTF-8 bytes, UTF-16, and line columns #227 Slice: Add branded coordinate adapters for UTF-8 bytes, UTF-16, and line columns
• Slice: Require basisHeadId and byteRange for every product textWindow read #228 Slice: Require basisHeadId and byteRange for every product textWindow read
• Slice: Separate authoritative line facts from rebuildable line indexes #229 Slice: Separate authoritative line facts from rebuildable line indexes
• Slice: Add materialization cache provenance and invalidation rules #230 Slice: Add materialization cache provenance and invalidation rules

CR-04 - Durability semantics in save, dirty, and footer

Goalpost: express queued intent, admitted causal history, saved file projection, local Git, and remote Git durability as separate states.

• Slice: Model Jim buffer durability ladder in workspace state #231 Slice: Model Jim buffer durability ladder in workspace state
• Slice: Compute dirty state from current RopeHead versus last save anchor #232 Slice: Compute dirty state from current RopeHead versus last save anchor
• Slice: Rework footer durability display around causal rope state #233 Slice: Rework footer durability display around causal rope state
• Slice: Compute +N/-N from causal rewrites since selected anchor #234 Slice: Compute +N/-N from causal rewrites since selected anchor

CR-05 - Causal gutter and modified line markers

Goalpost: compute gutter modified/deleted markers from rope rewrite and diff evidence, never from Git diff.

• Tick receipt gutter for Echo-backed editing #84 Tick receipt gutter for Echo-backed editing
• Slice: Derive modified gutter markers from rewrite and diff facts #235 Slice: Derive modified gutter markers from rewrite and diff facts
• Slice: Render deletion markers between surviving causal lines #236 Slice: Render deletion markers between surviving causal lines
• Slice: Add gutter ancestry basis setting #237 Slice: Add gutter ancestry basis setting
• Slice: Theme causal gutter markers using tokens only #238 Slice: Theme causal gutter markers using tokens only

CR-06 - Runtime-backed why evidence

Goalpost: make :why cite rope head, leaf, blob, rewrite, diff, tick, checkpoint, and anchor evidence from the runtime.

• Design rope fact inspector and range why UI #209 Design rope fact inspector and range why UI
• Slice: Explain range from RopeHead to leaf blob rewrite diff and tick #239 Slice: Explain range from RopeHead to leaf blob rewrite diff and tick
• Slice: Replace transient why toast with anchored evidence panel #240 Slice: Replace transient why toast with anchored evidence panel
• Slice: Add why witnesses for import edit save and generated text #241 Slice: Add why witnesses for import edit save and generated text
• Slice: Connect gutter and footer explainers to why evidence #242 Slice: Connect gutter and footer explainers to why evidence

CR-07 - Retention, balance, and performance witnesses

Goalpost: prove causal rope is not full-snapshot cosplay with retained-byte, subtree-identity, balance, and materialization-budget witnesses.

• Design graph-backed rope compaction policy #207 Design graph-backed rope compaction policy
• Design graph-backed rope rebalancing evidence #208 Design graph-backed rope rebalancing evidence
• Design graph-backed rope retention budget dashboard #210 Design graph-backed rope retention budget dashboard
• Slice: Add big-file retained authoritative bytes witness #243 Slice: Add big-file retained authoritative bytes witness
• Slice: Add untouched subtree identity path-copy witness #244 Slice: Add untouched subtree identity path-copy witness
• Slice: Enforce rope balance and leaf-size invariants #245 Slice: Enforce rope balance and leaf-size invariants
• Slice: Add CRLF and Unicode coordinate stress witnesses #246 Slice: Add CRLF and Unicode coordinate stress witnesses

CR-08 - Delete transitional text authority APIs

Goalpost: delete or quarantine all transitional full-root/snapshot authority APIs so only causal rope remains in product code.

• Design snapshot fixture import migration path #211 Design snapshot fixture import migration path
• Slice: Delete or quarantine HotTextBufferState full-root authority #247 Slice: Delete or quarantine HotTextBufferState full-root authority
• Slice: Move full-snapshot fixture under explicit test fixture namespace #248 Slice: Move full-snapshot fixture under explicit test fixture namespace
• Slice: Delete stale in-memory runtime aliases and generated import paths #249 Slice: Delete stale in-memory runtime aliases and generated import paths

CR-09 - Dogfood cutover and regression net

Goalpost: daily-drive Jim on causal rope, remove the snapshot escape hatch from dev startup, and lock the architecture with tests and docs.

• Slice: Run npm dev without snapshot authority escape hatch #250 Slice: Run npm dev without snapshot authority escape hatch
• Slice: End-to-end causal rope open edit save restart recovery #251 Slice: End-to-end causal rope open edit save restart recovery
• Slice: Large-file causal rope dogfood scenario #252 Slice: Large-file causal rope dogfood scenario
• Slice: External file reload as causal import or rebase event #253 Slice: External file reload as causal import or rebase event
• Slice: Publish causal rope architecture regression suite and docs #254 Slice: Publish causal rope architecture regression suite and docs

Hard no list

• Do not optimize the full-snapshot runtime instead of replacing it.
• Do not compute modified lines from Git diff.
• Do not make save reset causal history.
• Do not call a full-string root a RopeHead.
• Do not accept basis-less materialized reads.
• Do not allow fixture imports into installed product code.
• Do not treat CAS materializations as authority.