F12: inline editable proposed-change diff in the Markdown editor + Accept/Reject control parity (#64) (#66)

src/attributionController.ts

@@ -249,7 +249,7 @@ export class AttributionController implements vscode.Disposable {
     range: vscode.Range,
     newText: string,
     provenance: Provenance,
-    opts?: { expectedVersion?: number; turnId?: string },
+    opts?: { expectedVersion?: number; turnId?: string; landBaseline?: boolean },
   ): Promise<boolean> {
     if (!this.isTracked(document)) return false;
     if (opts?.expectedVersion !== undefined && document.version !== opts.expectedVersion) return false;
@@ -290,15 +290,25 @@ export class AttributionController implements vscode.Disposable {
         "(host minimized differently?) — the edit may be mis-attributed (INV-9).",
       );
     }
-    if (ok) {
-      // F6 (INV-18): a real machine landing — signal the baseline to advance so
-      // this text never shows as a change in the diff view. Fire regardless of
-      // attribution-match bookkeeping above; the landing happened either way.
+    if (ok && opts?.landBaseline !== false) {
+      // F6 (INV-18): a real machine landing — advance the baseline. F12 (INV-48)
+      // suppresses this for optimistic apply: the proposed text is in the buffer
+      // but the change stays PENDING (baseline at pre-proposal) until accept.
       this.applyEmitter.fire({ document });
     }
     return ok;
   }
 
+  /**
+   * F12/#64 (INV-51): fire the machine-landing signal WITHOUT applying text — used
+   * by finalize-in-place, where the proposed text already landed in the buffer via
+   * optimistic apply (`landBaseline:false`) and accept only needs to advance the
+   * F6 baseline so the now-accepted change stops reading as pending.
+   */
+  signalLanded(document: vscode.TextDocument): void {
+    if (this.isTracked(document)) this.applyEmitter.fire({ document });
+  }
+
   // ---- PUC-4: persistence on save ----------------------------------------------------
 
   private onDidSave(document: vscode.TextDocument): void {

src/editorProposalController.ts

@@ -0,0 +1,151 @@
+/**
+ * EditorProposalController — F12/#64 editor surface (spec coauthoring-inline-editor-diff
+ * §3.5). Reverses INV-32 for pending proposals: on `onDidChangeProposals` it
+ * (1) optimistically applies any not-yet-applied proposal into the active editor's
+ * buffer (ProposalController.optimisticApply, INV-48), (2) decorates each applied
+ * proposal — insertion tint over the proposed text + a non-editable struck-red hint
+ * for deletions (INV-52, decorationPlan/INV-49), and (3) provides a CodeLens
+ * `Accept ▾ / Reject ▾` above each block whose ▾ opens a QuickPick (this / all).
+ * Owns no proposal STATE — it is a view over ProposalController (which stays the
+ * pure F4 owner). A document with no pending proposals shows nothing (INV-32's
+ * spirit when nothing is pending).
+ */
+import * as vscode from "vscode";
+import type { ProposalController } from "./proposalController";
+import { decorationPlan } from "./trackChangesModel";
+import { isAuthorable } from "./workspacePath";
+
+export class EditorProposalController implements vscode.Disposable, vscode.CodeLensProvider {
+  private readonly disposables: vscode.Disposable[] = [];
+  private readonly insertionDeco = vscode.window.createTextEditorDecorationType({
+    backgroundColor: new vscode.ThemeColor("diffEditor.insertedTextBackground"),
+  });
+  private readonly deletionDeco = vscode.window.createTextEditorDecorationType({
+    // a non-editable struck-red hint injected AFTER the insertion (INV-52)
+    after: { color: new vscode.ThemeColor("gitDecoration.deletedResourceForeground") },
+    textDecoration: "none",
+  });
+  private readonly lensEmitter = new vscode.EventEmitter<void>();
+  readonly onDidChangeCodeLenses = this.lensEmitter.event;
+  /** Pending debounce timers — one per URI — coalesce rapid-fire propose events
+   * (e.g. runEditAndPropose's N sequential propose() calls) into a single
+   * optimistic-apply pass that runs after ALL proposals are created. Without this,
+   * each propose() fires onDidChangeProposals synchronously and the controller's
+   * optimisticApply runs concurrently with the still-in-progress propose loop,
+   * causing "file changed in the meantime" workspace-edit conflicts. */
+  private readonly pendingApply = new Map<string, ReturnType<typeof setTimeout>>();
+
+  constructor(private readonly proposals: ProposalController) {
+    this.disposables.push(
+      this.insertionDeco, this.deletionDeco, this.lensEmitter,
+      vscode.languages.registerCodeLensProvider({ language: "markdown" }, this),
+      this.proposals.onDidChangeProposals(({ uri }) => this.scheduleApply(uri)),
+      vscode.window.onDidChangeActiveTextEditor((ed) => ed && this.renderEditor(ed)),
+      // the four QuickPick-backed menu commands
+      vscode.commands.registerCommand("cowriting.proposalAcceptMenu", (id?: string) => this.menu("accept", id)),
+      vscode.commands.registerCommand("cowriting.proposalRejectMenu", (id?: string) => this.menu("reject", id)),
+    );
+  }
+
+  /** Debounce-schedule an optimistic-apply pass for the given URI. Multiple rapid
+   * onDidChangeProposals events (from a single runEditAndPropose batch) collapse
+   * into one pass that runs after the batch completes. */
+  private scheduleApply(uri: string): void {
+    const prev = this.pendingApply.get(uri);
+    if (prev !== undefined) clearTimeout(prev);
+    this.pendingApply.set(
+      uri,
+      setTimeout(() => {
+        this.pendingApply.delete(uri);
+        void this.onProposalsChanged(uri);
+      }, 0),
+    );
+  }
+
+  /** Apply any not-yet-applied proposals on the doc, then re-decorate + refresh lenses. */
+  private async onProposalsChanged(uri: string): Promise<void> {
+    const doc = vscode.workspace.textDocuments.find((d) => d.uri.toString() === uri);
+    if (!doc || doc.languageId !== "markdown" || !isAuthorable(doc.uri.scheme)) return;
+    const key = this.proposals.keyFor(doc);
+    for (const v of this.proposals.listProposals(doc)) {
+      if (v.anchorStart !== null && !this.proposals.isApplied(key, v.id)) {
+        await this.proposals.optimisticApply(doc, v.id); // fires onDidChangeProposals again; guarded by isApplied
+      }
+    }
+    const ed = vscode.window.visibleTextEditors.find((e) => e.document.uri.toString() === uri);
+    if (ed) this.renderEditor(ed);
+    this.lensEmitter.fire();
+  }
+
+  /** Decorate the editor for every applied proposal on its document (INV-52). */
+  private renderEditor(editor: vscode.TextEditor): void {
+    const doc = editor.document;
+    if (doc.languageId !== "markdown") {
+      editor.setDecorations(this.insertionDeco, []);
+      editor.setDecorations(this.deletionDeco, []);
+      return;
+    }
+    const key = this.proposals.keyFor(doc);
+    const insertions: vscode.Range[] = [];
+    const deletions: vscode.DecorationOptions[] = [];
+    for (const v of this.proposals.listProposals(doc)) {
+      if (v.anchorStart === null || v.original === undefined || !this.proposals.isApplied(key, v.id)) continue;
+      const plan = decorationPlan(v.anchorStart, v.original, v.replacement);
+      for (const ins of plan.insertions) {
+        insertions.push(new vscode.Range(doc.positionAt(ins.start), doc.positionAt(ins.end)));
+      }
+      for (const del of plan.deletions) {
+        deletions.push({
+          range: new vscode.Range(doc.positionAt(del.at), doc.positionAt(del.at)),
+          renderOptions: { after: { contentText: ` ${del.text} `, textDecoration: "line-through" } },
+        });
+      }
+    }
+    editor.setDecorations(this.insertionDeco, insertions);
+    editor.setDecorations(this.deletionDeco, deletions);
+  }
+
+  /** CodeLensProvider: a `Accept ▾` / `Reject ▾` pair above each applied block. */
+  provideCodeLenses(document: vscode.TextDocument): vscode.CodeLens[] {
+    if (document.languageId !== "markdown") return [];
+    const key = this.proposals.keyFor(document);
+    const lenses: vscode.CodeLens[] = [];
+    for (const v of this.proposals.listProposals(document)) {
+      if (v.anchorStart === null || !this.proposals.isApplied(key, v.id)) continue;
+      const pos = document.positionAt(v.anchorStart);
+      const line = new vscode.Range(pos.line, 0, pos.line, 0);
+      lenses.push(
+        new vscode.CodeLens(line, { title: "Accept ▾", command: "cowriting.proposalAcceptMenu", arguments: [v.id] }),
+        new vscode.CodeLens(line, { title: "Reject ▾", command: "cowriting.proposalRejectMenu", arguments: [v.id] }),
+      );
+    }
+    return lenses;
+  }
+
+  /** The dropdown: this-proposal vs all-proposals, then dispatch. */
+  private async menu(kind: "accept" | "reject", id?: string): Promise<void> {
+    const doc = vscode.window.activeTextEditor?.document;
+    if (!doc || !id) return;
+    const key = this.proposals.keyFor(doc);
+    const verb = kind === "accept" ? "Accept" : "Reject";
+    const pick = await vscode.window.showQuickPick(
+      [`${verb} this proposal`, `${verb} ALL proposals`],
+      { placeHolder: `${verb} Claude's proposal` },
+    );
+    if (!pick) return;
+    const all = pick.includes("ALL");
+    if (kind === "accept") {
+      if (all) await this.proposals.acceptAllProposals(doc);
+      else await this.proposals.finalizeInPlace(key, id);
+    } else {
+      if (all) await this.proposals.rejectAll(doc);
+      else await this.proposals.revertInPlace(key, id);
+    }
+  }
+
+  dispose(): void {
+    for (const t of this.pendingApply.values()) clearTimeout(t);
+    this.pendingApply.clear();
+    for (const d of this.disposables) d.dispose();
+  }
+}

src/extension.ts

@@ -12,6 +12,7 @@ import { SidecarRouter } from "./sidecarRouter";
 import { DiffViewController } from "./diffViewController";
 import { TrackChangesPreviewController } from "./trackChangesPreview";
 import { LiveProgressUi } from "./liveProgressUi";
+import { EditorProposalController } from "./editorProposalController";
 import { isAuthorable, routeEdit, selectionRejection } from "./workspacePath";
 
 const CHANNEL_NAME = "Cowriting (Cline SDK)";
@@ -25,6 +26,7 @@ export interface CowritingApi {
   trackChangesPreviewController: TrackChangesPreviewController;
   sidecarRouter: SidecarRouter;
   liveProgressUi: LiveProgressUi;
+  editorProposalController: EditorProposalController;
 }
 
 export function activate(context: vscode.ExtensionContext): CowritingApi | undefined {
@@ -115,6 +117,11 @@ export function activate(context: vscode.ExtensionContext): CowritingApi | undef
   );
   context.subscriptions.push(trackChangesPreviewController);
 
+  // --- F12 (#64): the editor surface — optimistic-apply proposals into the buffer,
+  // decorate the diff, and provide Accept ▾/Reject ▾ CodeLens (INV-48/49/52/53). ---
+  const editorProposalController = new EditorProposalController(proposalController);
+  context.subscriptions.push(editorProposalController);
+
   // #46 (INV-42): accept every pending proposal on the active doc in one gesture
   // (also reachable from the preview toolbar's "Accept all" button). Reuses the
   // batched F4 seam + reports applied-vs-skipped.
@@ -129,6 +136,18 @@ export function activate(context: vscode.ExtensionContext): CowritingApi | undef
     }),
   );
 
+  // #64 (INV-53): reject every pending proposal on the active doc in one gesture.
+  context.subscriptions.push(
+    vscode.commands.registerCommand("cowriting.rejectAllProposals", async () => {
+      const doc = vscode.window.activeTextEditor?.document;
+      if (!doc || doc.languageId !== "markdown") {
+        void vscode.window.showWarningMessage("Cowriting: open a Markdown document to reject its proposals.");
+        return;
+      }
+      await trackChangesPreviewController.rejectAll(doc);
+    }),
+  );
+
   // --- F6 machine-landing wiring — now for ANY authorable doc ---
   // The seam's single machine-landing signal advances the F6 baseline (INV-18);
   // the seam can now fire on out-of-folder files too, so wire it unconditionally.
@@ -342,6 +361,7 @@ export function activate(context: vscode.ExtensionContext): CowritingApi | undef
     trackChangesPreviewController,
     sidecarRouter,
     liveProgressUi,
+    editorProposalController,
   };
 }
 

src/model.ts

@@ -97,6 +97,14 @@ export interface Proposal {
    * back-compat with older sidecars) ⇒ a single-range proposal accepted whole.
    */
   granularity?: "block" | "single";
+  /**
+   * F12/#64 (INV-48): the pre-apply text, captured when a proposal is
+   * optimistically applied to the buffer. `replacement` is now in the buffer and
+   * `fp.text` re-anchors to it, so `original` is the only record of what to revert
+   * to (revert-in-place) and what to show struck in the `<del>` half. Absent on a
+   * proposal created but not yet optimistically applied (or older sidecars).
+   */
+  original?: string;
 }
 
 export interface Artifact {
@@ -252,6 +260,8 @@ export function serializeArtifact(a: Artifact): string {
             createdAt: p.createdAt,
             ...(p.turnId !== undefined ? { turnId: p.turnId } : {}),
             ...(p.instruction !== undefined ? { instruction: p.instruction } : {}),
+            ...(p.original !== undefined ? { original: p.original } : {}),
+            ...(p.granularity !== undefined ? { granularity: p.granularity } : {}),
           },
           p,
         ),

src/proposalController.ts

@@ -13,8 +13,8 @@
 import * as vscode from "vscode";
 import { SidecarRouter, docIdentity } from "./sidecarRouter";
 import { emptyArtifact, type Artifact, type Fingerprint, type Proposal, type Provenance } from "./model";
-import { resolve, shift, type OffsetRange } from "./anchorer";
-import { addProposal, removeProposal } from "./proposalModel";
+import { resolve, shift, buildFingerprint, type OffsetRange } from "./anchorer";
+import { addProposal, removeProposal, setProposalApplied } from "./proposalModel";
 import type { AttributionController } from "./attributionController";
 import type { VersionGuard } from "./versionGuard";
 import { isAuthorable } from "./workspacePath";
@@ -39,6 +39,8 @@ interface DocState {
   live: Map<string, OffsetRange>;
   /** proposal ids whose anchor did not resolve at last render (stale/orphaned). */
   unresolved: Set<string>;
+  /** ids already optimistically applied to the buffer (so the trigger doesn't re-apply). */
+  applied: Set<string>;
 }
 
 export class ProposalController implements vscode.Disposable {
@@ -89,8 +91,9 @@ export class ProposalController implements vscode.Disposable {
         id: p.id,
         anchorStart: resolved === "orphaned" ? null : resolved.start,
         anchorEnd: resolved === "orphaned" ? null : resolved.end,
-        replaced: fp?.text ?? "",
+        replaced: p.original ?? fp?.text ?? "",
         replacement: p.replacement,
+        original: p.original,
       };
     });
   }
@@ -104,6 +107,7 @@ export class ProposalController implements vscode.Disposable {
         artifact: this.store.load(docPath) ?? emptyArtifact(docPath),
         live: new Map(),
         unresolved: new Set(),
+        applied: new Set(),
       };
       this.docs.set(docPath, state);
     }
@@ -137,8 +141,33 @@ export class ProposalController implements vscode.Disposable {
 
   // ---- PUC-2/PUC-3: accept / reject (INV-11/INV-12) ----------------------------------
 
-  /** Accept by proposal id (test-facing twin of the thread-menu gesture). */
+  /** Accept by id — F12: finalize the already-applied text in place (INV-51). */
   async acceptById(docPath: string, proposalId: string, opts?: { silent?: boolean }): Promise<boolean> {
+    if (this.isApplied(docPath, proposalId)) {
+      // INV-11 (applied path): if an external write mangled the optimistically-applied
+      // text so the fingerprint no longer resolves, refuse finalize — same guard as the
+      // legacy accept path.  Direct finalizeInPlace calls (CodeLens Accept gesture where
+      // the user may have edited inside the applied span) bypass this check intentionally.
+      const hit = this.byId(docPath, proposalId);
+      if (hit) {
+        const document = this.openDoc(hit.state);
+        if (document) {
+          const fp = hit.state.artifact.anchors[hit.proposal.anchorId]?.fingerprint;
+          const resolved = fp ? resolve(document.getText(), fp) : "orphaned";
+          if (resolved === "orphaned") {
+            if (!opts?.silent) {
+              void vscode.window.showWarningMessage(
+                "Cowriting: this proposal's target text changed or is missing — undo to restore it, or reject to discard (it is never applied by guess).",
+              );
+            }
+            return false;
+          }
+        }
+      }
+      return this.finalizeInPlace(docPath, proposalId);
+    }
+    // Fallback: a proposal that was never optimistically applied (e.g. orphaned at
+    // apply time) keeps the legacy seam-apply accept.
     const hit = this.byId(docPath, proposalId);
     return hit ? this.accept(hit.state, hit.proposal, opts) : false;
   }
@@ -181,6 +210,12 @@ export class ProposalController implements vscode.Disposable {
     return true;
   }
 
+  /** Reject by id — F12: revert the applied text in place (INV-51). */
+  async rejectByIdInPlace(docPath: string, proposalId: string): Promise<boolean> {
+    if (this.isApplied(docPath, proposalId)) return this.revertInPlace(docPath, proposalId);
+    return this.rejectById(docPath, proposalId);
+  }
+
   private async accept(state: DocState, proposal: Proposal, opts?: { silent?: boolean }): Promise<boolean> {
     if (this.guard.isReadOnly(state.docPath)) return false;
     const document = this.openDoc(state);
@@ -257,6 +292,158 @@ export class ProposalController implements vscode.Disposable {
     return true;
   }
 
+  /** True once this proposal's text is in the buffer (optimistic apply ran). */
+  isApplied(docPath: string, proposalId: string): boolean {
+    return this.docs.get(docPath)?.applied.has(proposalId) ?? false;
+  }
+
+  /**
+   * F12/#64 (INV-48): optimistically apply a pending proposal INTO the buffer so
+   * the editor shows the would-be-accepted result (editable). Reuses the F4
+   * word-precise seam (block → per-word hunks, INV-40; single → whole range) but
+   * with `landBaseline:false` (the change stays pending). Then re-anchors the
+   * proposal to the applied text and stores the original (`setProposalApplied`), so
+   * `resolve()` finds it in the mutated buffer and revert/decorate key off it.
+   * Idempotent: a no-op if already applied.
+   */
+  async optimisticApply(document: vscode.TextDocument, proposalId: string): Promise<boolean> {
+    if (!this.isTracked(document) || this.guard.isReadOnly(this.keyOf(document))) return false;
+    const docPath = this.keyOf(document);
+    const state = this.ensureState(document);
+    if (state.applied.has(proposalId)) return true;
+    state.artifact = this.store.load(docPath) ?? emptyArtifact(docPath);
+    const proposal = state.artifact.proposals.find((p) => p.id === proposalId);
+    const fp = proposal ? state.artifact.anchors[proposal.anchorId]?.fingerprint : undefined;
+    if (!proposal || !fp) return false;
+    // Reload-safety (INV-51/54): a proposal that already carries `original` was
+    // optimistically applied in a PRIOR session — the buffer holds the applied text
+    // and `fp` points at it, but this (fresh) controller's in-memory `applied` set is
+    // empty. Re-applying would recapture `original` from the already-applied buffer
+    // (= the replacement) and CLOBBER the true revert target, breaking Reject. Mark it
+    // applied in memory and stop — `original` is captured exactly once, on first apply.
+    if (proposal.original !== undefined) {
+      state.applied.add(proposalId);
+      this.renderAll(document);
+      return true;
+    }
+    const resolved = resolve(document.getText(), fp);
+    if (resolved === "orphaned") return false;
+    const original = document.getText(
+      new vscode.Range(document.positionAt(resolved.start), document.positionAt(resolved.end)),
+    );
+    const ok =
+      proposal.granularity === "block"
+        ? await this.applyBlockOptimistic(document, resolved, proposal)
+        : await this.attribution.applyAgentEdit(
+            document,
+            new vscode.Range(document.positionAt(resolved.start), document.positionAt(resolved.end)),
+            proposal.replacement,
+            proposal.author,
+            { expectedVersion: document.version, turnId: proposal.turnId, landBaseline: false },
+          );
+    if (!ok) return false;
+    state.applied.add(proposalId);
+    // Re-anchor to the applied text now in the buffer (its start is unchanged; its
+    // end shifts by the net length delta of the replacement).
+    const appliedStart = resolved.start;
+    const appliedEnd = appliedStart + proposal.replacement.length;
+    const appliedFp = buildFingerprint(document.getText(), { start: appliedStart, end: appliedEnd });
+    this.store.update(docPath, (a) => setProposalApplied(a, proposalId, appliedFp, original));
+    this.renderAll(document);
+    return true;
+  }
+
+  /** Block optimistic apply: the INV-40 per-word hunks, but landBaseline:false. */
+  private async applyBlockOptimistic(
+    document: vscode.TextDocument,
+    resolved: OffsetRange,
+    proposal: Proposal,
+  ): Promise<boolean> {
+    const blockText = document.getText(
+      new vscode.Range(document.positionAt(resolved.start), document.positionAt(resolved.end)),
+    );
+    const subHunks = wordEditHunks(blockText, proposal.replacement);
+    if (subHunks.length === 0) return true;
+    for (const h of [...subHunks].sort((a, b) => b.start - a.start)) {
+      const range = new vscode.Range(
+        document.positionAt(resolved.start + h.start),
+        document.positionAt(resolved.start + h.end),
+      );
+      const ok = await this.attribution.applyAgentEdit(document, range, h.replacement, proposal.author, {
+        expectedVersion: document.version, turnId: proposal.turnId, landBaseline: false,
+      });
+      if (!ok) return false;
+    }
+    return true;
+  }
+
+  /**
+   * F12/#64 (INV-51): ACCEPT an optimistically-applied proposal — the text is
+   * already in the buffer, so this only advances the F6 baseline (machine-landing,
+   * via `attribution.signalLanded`) and clears the proposal. No re-application.
+   */
+  async finalizeInPlace(docPath: string, proposalId: string): Promise<boolean> {
+    const hit = this.byId(docPath, proposalId);
+    if (!hit) return false;
+    const document = this.openDoc(hit.state);
+    if (!document) return false;
+    this.attribution.signalLanded(document);
+    this.store.update(docPath, (a) => removeProposal(a, proposalId));
+    hit.state.applied.delete(proposalId);
+    this.renderAll(document);
+    return true;
+  }
+
+  /**
+   * F12/#64 (INV-51): REJECT an optimistically-applied proposal — replace its live
+   * applied span with the stored `original`, then clear it. Reverts the whole block
+   * regardless of any in-place edits the human made to the inserted text.
+   */
+  async revertInPlace(docPath: string, proposalId: string): Promise<boolean> {
+    const hit = this.byId(docPath, proposalId);
+    if (!hit) return false;
+    const document = this.openDoc(hit.state);
+    if (!document) return false;
+    const fp = hit.state.artifact.anchors[hit.proposal.anchorId]?.fingerprint;
+    const resolved = fp ? resolve(document.getText(), fp) : "orphaned";
+    if (resolved !== "orphaned" && hit.proposal.original !== undefined) {
+      const we = new vscode.WorkspaceEdit();
+      we.replace(
+        document.uri,
+        new vscode.Range(document.positionAt(resolved.start), document.positionAt(resolved.end)),
+        hit.proposal.original,
+      );
+      if (!(await vscode.workspace.applyEdit(we))) return false;
+    }
+    this.store.update(docPath, (a) => removeProposal(a, proposalId));
+    hit.state.applied.delete(proposalId);
+    this.renderAll(document);
+    return true;
+  }
+
+  /**
+   * F12/#64 (INV-53): reject EVERY pending proposal on a document — revert each in
+   * DESCENDING anchor order (so an earlier revert never shifts a later one's
+   * offsets), symmetric with #46's accept-all. Returns the reverted count.
+   */
+  async rejectAll(document: vscode.TextDocument): Promise<{ reverted: number }> {
+    if (!this.isTracked(document)) return { reverted: 0 };
+    const docPath = this.keyOf(document);
+    const state = this.ensureState(document);
+    state.artifact = this.store.load(docPath) ?? emptyArtifact(docPath);
+    const text = document.getText();
+    const ordered = state.artifact.proposals
+      .map((p) => {
+        const fp = state.artifact.anchors[p.anchorId]?.fingerprint;
+        const r = fp ? resolve(text, fp) : "orphaned";
+        return { id: p.id, start: r === "orphaned" ? -1 : r.start };
+      })
+      .sort((a, b) => b.start - a.start);
+    let reverted = 0;
+    for (const it of ordered) if (await this.revertInPlace(docPath, it.id)) reverted++;
+    return { reverted };
+  }
+
   private reject(state: DocState, proposal: Proposal): void {
     if (this.guard.isReadOnly(state.docPath)) return;
     this.store.update(state.docPath, (a) => removeProposal(a, proposal.id));

src/proposalModel.ts

@@ -37,6 +37,25 @@ export function removeProposal(artifact: Artifact, proposalId: string): boolean
   return artifact.proposals.length < before;
 }
 
+/**
+ * F12/#64 (INV-48): record a proposal as optimistically applied — store the
+ * pre-apply `original` (for revert + the struck `<del>`) and re-point its anchor
+ * fingerprint to the now-in-buffer applied text so `resolve()` finds it. Idempotent
+ * shape: a second call simply overwrites with the same values.
+ */
+export function setProposalApplied(
+  artifact: Artifact,
+  proposalId: string,
+  appliedFp: Fingerprint,
+  original: string,
+): boolean {
+  const p = artifact.proposals.find((x) => x.id === proposalId);
+  if (!p) return false;
+  p.original = original;
+  artifact.anchors[p.anchorId] = { fingerprint: appliedFp };
+  return true;
+}
+
 /** Markdown comment body: instruction header + fenced whole-range diff. */
 export function proposalBody(targetText: string, p: Proposal): string {
   const header = p.instruction ? `**Claude proposes** — _${p.instruction}_` : "**Claude proposes**";

src/trackChangesModel.ts

@@ -263,6 +263,42 @@ export function wordEditHunks(currentText: string, rewrittenText: string): EditH
   return hunks;
 }
 
+/** F12/#64 (INV-49/52): the editor render of one optimistically-applied proposal. */
+export interface DecorationPlan {
+  /** buffer ranges of inserted (proposed) text → tinted (INV-52). */
+  insertions: { start: number; end: number }[];
+  /** struck original text shown as a non-editable hint at a buffer offset (INV-52). */
+  deletions: { at: number; text: string }[];
+}
+
+/**
+ * F12/#64 (INV-49): compute the editor decoration plan for a proposal whose applied
+ * text occupies `[anchorStart, anchorStart+replacement.length)` in the buffer. The
+ * SAME word diff the webview uses (`wordEditHunks`) drives it, so both surfaces show
+ * the identical diff. A changed run maps to (a) an insertion range over the run's
+ * applied text and (b) a deletion hint carrying the run's removed original text at
+ * the run start; a pure insertion has no deletion hint; a pure deletion has only a
+ * hint. Pure, vscode-free, deterministic.
+ */
+export function decorationPlan(anchorStart: number, original: string, replacement: string): DecorationPlan {
+  const insertions: { start: number; end: number }[] = [];
+  const deletions: { at: number; text: string }[] = [];
+  // Walk the word diff once, tracking the applied-side offset as we consume parts.
+  let appliedOffset = anchorStart;
+  for (const part of diffWordsWithSpace(original, replacement)) {
+    if (part.added) {
+      insertions.push({ start: appliedOffset, end: appliedOffset + part.value.length });
+      appliedOffset += part.value.length;
+    } else if (part.removed) {
+      deletions.push({ at: appliedOffset, text: part.value });
+      // removed text is NOT in the applied buffer → appliedOffset does not advance
+    } else {
+      appliedOffset += part.value.length;
+    }
+  }
+  return { insertions, deletions };
+}
+
 const isWs = (c: string): boolean => /\s/.test(c);
 
 /**
@@ -701,6 +737,8 @@ export interface ProposalView {
   replaced: string;
   /** the proposed replacement text. */
   replacement: string;
+  /** F12/#64 (INV-48): the pre-apply original, set after optimistic apply. */
+  original?: string;
 }
 
 function proposalBlockHtml(p: ProposalView, render: (src: string) => string): string {
@@ -716,8 +754,14 @@ function proposalBlockHtml(p: ProposalView, render: (src: string) => string): st
   const after = `<ins class="cw-add">${safe(p.replacement)}</ins>`;
   const actions =
     `<span class="cw-actions">` +
-    `<button class="cw-accept" data-action="accept">✓</button>` +
-    `<button class="cw-reject" data-action="reject">✗</button>` +
+    `<span class="cw-btngroup">` +
+    `<button class="cw-accept" data-action="accept">Accept</button>` +
+    `<button class="cw-caret" data-action="acceptAll" title="Accept all pending proposals">▾</button>` +
+    `</span>` +
+    `<span class="cw-btngroup">` +
+    `<button class="cw-reject" data-action="reject">Reject</button>` +
+    `<button class="cw-caret" data-action="rejectAll" title="Reject all pending proposals">▾</button>` +
+    `</span>` +
     `</span>`;
   return `<div class="cw-proposal${unanchored}" data-proposal-id="${md.utils.escapeHtml(p.id)}">${actions}${before}${after}</div>`;
 }
@@ -747,6 +791,26 @@ function renderReviewOp(
  * INV-34). Deterministic: proposals in the same block are ordered by anchorStart
  * then id; trailing proposals keep input order.
  */
+/**
+ * F12/#64 (INV-50): `currentText` with every resolved pending proposal's applied
+ * span reverted to its original (`replaced`) — the "landed" text the baseline diff
+ * should run against, so a pending proposal renders ONCE (as a proposal), never also
+ * as a landed change. Reverts high→low so earlier offsets stay valid. Pure. The
+ * preview's summary tally diffs against this too, so the toolbar count matches the
+ * body (a pending change is not double-counted as both a landed add/remove and a
+ * proposal).
+ */
+export function landedTextOf(currentText: string, proposals: ProposalView[]): string {
+  const pendingApplied = proposals
+    .filter((p) => p.anchorStart !== null)
+    .sort((a, b) => b.anchorStart! - a.anchorStart!);
+  let landedText = currentText;
+  for (const p of pendingApplied) {
+    landedText = landedText.slice(0, p.anchorStart!) + p.replaced + landedText.slice(p.anchorEnd!);
+  }
+  return landedText;
+}
+
 export function renderReview(
   baselineText: string,
   currentText: string,
@@ -755,8 +819,18 @@ export function renderReview(
   opts: RenderOptions = {},
 ): string {
   const render = opts.render ?? defaultRender;
-  const ranges = splitBlocksWithRanges(currentText);
-  const ops = diffBlocks(baselineText, currentText);
+
+  // F12/#64 (INV-50): with optimistic apply the proposed text is already in
+  // `currentText`, so a naive baseline→current diff would render each proposed
+  // change BOTH as a landed diff and as its proposal block. Diff against the
+  // "landed" text (current minus pending proposals) so they render once.
+  const pendingApplied = proposals
+    .filter((p) => p.anchorStart !== null)
+    .sort((a, b) => b.anchorStart! - a.anchorStart!);
+  const landedText = landedTextOf(currentText, proposals);
+
+  const ranges = splitBlocksWithRanges(landedText);
+  const ops = diffBlocks(baselineText, landedText);
   // #48: right after a PIN (baseline reason "pinned") with no changes since, the
   // panel is fully clean: no change marks (already absent) AND no authorship
   // coloring, so the pin reads as "this is my clean starting point". Skip
@@ -766,7 +840,28 @@ export function renderReview(
   // its authorship coloring (F10 INV-33), so this is gated on the pin specifically.
   const clean = opts.pinned === true && ops.every((o) => o.kind === "unchanged");
 
-  // Associate each resolved proposal with the current-side block index whose range
+  // Map a currentText offset to its landedText offset (account for reverted spans
+  // that precede it; reverts were applied high→low so the cumulative delta is stable).
+  const toLanded = (curOff: number): number => {
+    let delta = 0;
+    for (const p of [...pendingApplied].sort((a, b) => a.anchorStart! - b.anchorStart!)) {
+      if (p.anchorStart! < curOff) delta += p.replaced.length - (p.anchorEnd! - p.anchorStart!);
+    }
+    return curOff + delta;
+  };
+
+  // F12/#64 (INV-49/50): blocks are split from `landedText`, so `blk.start` is a
+  // landedText offset — but `authorSpans` arrive in `currentText` coordinates. A
+  // colored block sitting AFTER a length-changing pending proposal would otherwise
+  // be mis-colored (the offsets diverge by the revert delta). Map the spans into
+  // landedText coordinates once so authorship coloring stays aligned.
+  const landedSpans: AuthorSpan[] = authorSpans.map((s) => ({
+    ...s,
+    start: toLanded(s.start),
+    end: toLanded(s.end),
+  }));
+
+  // Associate each resolved proposal with the landedText block index whose range
   // it anchors into: the largest block with start <= anchorStart (the containing
   // block, or the nearest preceding block when the anchor sits in a gap). A
   // resolved anchor before all blocks, and every unresolved proposal, trails.
@@ -778,7 +873,7 @@ export function renderReview(
   const byBlock = new Map<number, ProposalView[]>();
   const trailing: ProposalView[] = [];
   for (const p of proposals) {
-    const j = p.anchorStart === null ? -1 : blockOf(p.anchorStart);
+    const j = p.anchorStart === null ? -1 : blockOf(toLanded(p.anchorStart));
     if (j < 0) {
       trailing.push(p);
       continue;
@@ -795,7 +890,7 @@ export function renderReview(
     const blockIndex = op.kind === "removed" ? -1 : ci;
     const blk = op.kind === "removed" ? undefined : ranges[ci++];
     const colored = (raw: string): string =>
-      blk && !clean ? colorByAuthor(raw, blk.start, authorSpans, render) : render(raw);
+      blk && !clean ? colorByAuthor(raw, blk.start, landedSpans, render) : render(raw);
     bodyParts.push(renderReviewOp(op, render, colored, srcAttr(blk)));
     const here = blockIndex >= 0 ? byBlock.get(blockIndex) : undefined;
     if (here) for (const p of here) bodyParts.push(proposalBlockHtml(p, render));

src/trackChangesPreview.ts

@@ -13,7 +13,7 @@ import * as vscode from "vscode";
 import type { DiffViewController } from "./diffViewController";
 import type { AttributionController } from "./attributionController";
 import type { ProposalController } from "./proposalController";
-import { renderReview, renderPlain, diffBlocks, diffToBlockHunks, type BlockOp } from "./trackChangesModel";
+import { renderReview, renderPlain, diffBlocks, diffToBlockHunks, landedTextOf, type BlockOp } from "./trackChangesModel";
 import { buildFingerprint } from "./anchorer";
 import { isAuthorable } from "./workspacePath";
 import type { EditTurnResult, RunEditTurnOptions } from "./liveTurn";
@@ -44,7 +44,8 @@ type ToolbarMsg =
   | { type: "pinBaseline" }
   | { type: "askClaude"; scope: "document" }
   | { type: "askClaude"; scope: "selection"; start: number; end: number }
-  | { type: "acceptAll" };
+  | { type: "acceptAll" }
+  | { type: "rejectAll" };
 
 export class TrackChangesPreviewController implements vscode.Disposable {
   private readonly disposables: vscode.Disposable[] = [];
@@ -196,8 +197,7 @@ export class TrackChangesPreviewController implements vscode.Disposable {
         .acceptById(this.proposals.keyFor(document), m.proposalId)
         .then(() => this.refresh(document));
     } else if (m?.type === "reject" && m.proposalId) {
-      this.proposals.rejectById(this.proposals.keyFor(document), m.proposalId);
-      this.refresh(document);
+      void this.proposals.rejectByIdInPlace(this.proposals.keyFor(document), m.proposalId).then(() => this.refresh(document));
     } else if (m?.type === "pinBaseline") {
       // F6 baseline store re-render arrives via the onDidChangeBaseline subscription.
       this.diffView.pin(document);
@@ -208,6 +208,8 @@ export class TrackChangesPreviewController implements vscode.Disposable {
     } else if (m?.type === "acceptAll") {
       // #46 (INV-42): batch-accept every pending proposal on this doc, then report.
       void this.acceptAll(document);
+    } else if (m?.type === "rejectAll") {
+      void this.rejectAll(document);
     }
   }
 
@@ -228,6 +230,17 @@ export class TrackChangesPreviewController implements vscode.Disposable {
     );
   }
 
+  /** #64 (INV-53): revert every pending proposal on the document; report the count. */
+  async rejectAll(document: vscode.TextDocument): Promise<void> {
+    const { reverted } = await this.proposals.rejectAll(document);
+    this.refresh(document);
+    if (reverted > 0) {
+      void vscode.window.showInformationMessage(
+        `Cowriting: rejected ${reverted} proposal${reverted === 1 ? "" : "s"}.`,
+      );
+    }
+  }
+
   /**
    * F11 (PUC-3/4): prompt host-side for the instruction (keeps the LLM/secret
    * surface out of the sealed webview, INV-8/35), run the edit turn, and surface
@@ -359,9 +372,13 @@ export class TrackChangesPreviewController implements vscode.Disposable {
     }
     const spans = this.attribution.spansFor(document);
     const proposals = this.proposals.listProposals(document);
+    // F12/#64 (INV-50): count added/removed against the LANDED text (current minus
+    // pending proposals), matching the body — a pending change shows once, as a
+    // proposal, and is not also tallied as a landed add/remove.
+    const landedOps = diffBlocks(baselineText, landedTextOf(current, proposals));
     const summary = {
-      added: ops.filter((o) => o.kind === "added").length,
-      removed: ops.filter((o) => o.kind === "removed").length,
+      added: landedOps.filter((o) => o.kind === "added").length,
+      removed: landedOps.filter((o) => o.kind === "removed").length,
       proposals: proposals.length,
     };
     void panel.webview.postMessage({