feat(ai): add AI-assisted commit splitting flow

Introduce a split-planning path for staged changes that asks supported AI
providers to group files into ordered Conventional Commit messages. The
plan is validated before execution so every staged file is assigned once
and unsafe states are rejected.

A new dialog lets users review and adjust the proposed groups before
creating the commits in sequence, with safeguards to preserve remaining
changes if something fails.

src/App.svelte

@@ -10,6 +10,7 @@
   import RepoTabs from "./lib/RepoTabs.svelte";
   import AiSettingsDialog from "./lib/components/AiSettingsDialog.svelte";
   import AiReviewDialog from "./lib/components/AiReviewDialog.svelte";
+  import AiCommitSplitDialog from "./lib/components/AiCommitSplitDialog.svelte";
   import AnalyticsNoticeDialog from "./lib/components/AnalyticsNoticeDialog.svelte";
   import AppSettingsDialog from "./lib/components/AppSettingsDialog.svelte";
   import BranchDeleteConfirmDialog from "./lib/components/BranchDeleteConfirmDialog.svelte";
@@ -51,6 +52,7 @@
     commit,
     commitAiGenerate,
     commitAiReview,
+    commitAiSplit,
     commitAiLoad,
     commitAiLocalModels,
     commitAiStatus,
@@ -129,6 +131,7 @@
 
   import type {
     AiReviewResult,
+    AiCommitPlan,
     AiSettings,
     AppLanguage,
     AppTheme,
@@ -293,6 +296,9 @@
   let commitAiPhase: CommitAiPhase = "idle";
   let commitAiGenerating = false;
   let commitAiReviewing = false;
+  let commitAiSplitting = false;
+  let aiCommitPlan: AiCommitPlan | null = null;
+  let aiCommitSplitOpen = false;
   let aiReviewResult: AiReviewResult | null = null;
   let aiReviewOpen = false;
   let commitAiPollTimer: ReturnType<typeof setInterval> | undefined;
@@ -1034,6 +1040,75 @@
     }
   }
 
+  async function splitStagedWithAi() {
+    if (!activeRepoPath || commitAiSplitting || stagedCount < 2) return;
+    if (aiSettings.provider === "local") {
+      errorMessage = "Commit splitting currently requires OpenAI, Anthropic, or a custom endpoint.";
+      return;
+    }
+    commitAiSplitting = true;
+    errorMessage = "";
+    try {
+      if (aiSettings.provider === "openai") {
+        const cred = await credLoad("ai:openai");
+        aiCommitPlan = await commitAiSplit(activeRepoPath, { provider: "openai", model: aiSettings.openaiModel, apiKey: cred?.password });
+      } else if (aiSettings.provider === "anthropic") {
+        const cred = await credLoad("ai:anthropic");
+        aiCommitPlan = await commitAiSplit(activeRepoPath, { provider: "anthropic", model: aiSettings.anthropicModel, apiKey: cred?.password });
+      } else {
+        const cred = await credLoad("ai:custom");
+        aiCommitPlan = await commitAiSplit(activeRepoPath, {
+          provider: "custom", model: aiSettings.customModel, baseUrl: aiSettings.customBaseUrl, apiKey: cred?.password,
+        });
+      }
+      aiCommitSplitOpen = true;
+      trackEvent("ai_commit_split_planned", { provider: aiSettings.provider, groups: aiCommitPlan.groups.length });
+    } catch (error) {
+      errorMessage = errorToMessage(error);
+    } finally {
+      commitAiSplitting = false;
+    }
+  }
+
+  async function applyAiCommitPlan(plan: AiCommitPlan) {
+    if (!activeRepoPath || isBusy || commitAiSplitting) return;
+    const allFiles = plan.groups.flatMap((group) => group.files);
+    if (plan.groups.length < 2 || plan.groups.some((group) => !group.message.trim() || group.files.length === 0)) return;
+    const currentStaged = changedFiles.filter((file) => file.staged !== null).map((file) => file.path).sort();
+    if (currentStaged.join("\n") !== [...allFiles].sort().join("\n")) {
+      errorMessage = "The staged files changed after the plan was created. Generate a new split plan.";
+      return;
+    }
+    if (changedFiles.some((file) => file.staged !== null && file.unstaged !== null)) {
+      errorMessage = "A file now has both staged and unstaged changes. Stage or discard the remaining changes first.";
+      return;
+    }
+
+    commitAiSplitting = true;
+    await runOperation("Creating split commits", async () => {
+      applyStatus(await unstageFiles(activeRepoPath, currentStaged));
+      let completed = 0;
+      try {
+        for (const group of plan.groups) {
+          applyStatus(await stageFiles(activeRepoPath, group.files));
+          applyStatus(await commit(activeRepoPath, group.message.trim()));
+          completed += 1;
+        }
+      } catch (error) {
+        throw new Error(`${completed} of ${plan.groups.length} commits were created. Remaining changes are preserved and can be staged again. ${errorToMessage(error)}`);
+      }
+      aiCommitSplitOpen = false;
+      aiCommitPlan = null;
+      commitMessage = "";
+      await refreshBranchList(activeRepoPath);
+      await refreshCommitHistory(activeRepoPath);
+      await refreshExplorerFiles(activeRepoPath);
+      await refreshFileHistory(activeRepoPath);
+      trackEvent("ai_commit_split_applied", { groups: plan.groups.length, files: allFiles.length });
+    });
+    commitAiSplitting = false;
+  }
+
   // ── Updates ────────────────────────────────────────────────────────────────
 
   async function checkForUpdates() {
@@ -4440,12 +4515,14 @@
             {commitAiPhase}
             {commitAiGenerating}
             {commitAiReviewing}
+            {commitAiSplitting}
             {canAmend}
             {amendMode}
             onCommit={commitChanges}
             onCommitMessageChange={updateCommitMessage}
             onGenerateCommitMessage={generateCommitMessageWithAi}
             onReviewStaged={reviewStagedWithAi}
+            onSplitStaged={splitStagedWithAi}
             onOpenAiSettings={() => { aiSettingsOpen = true; }}
             onToggleAmend={toggleAmendMode}
             onUndoLastCommit={undoLastCommitChange}
@@ -4588,6 +4665,15 @@
   />
 {/if}
 
+{#if aiCommitSplitOpen && aiCommitPlan}
+  <AiCommitSplitDialog
+    plan={aiCommitPlan}
+    isApplying={commitAiSplitting}
+    onApply={applyAiCommitPlan}
+    onClose={() => { if (!commitAiSplitting) aiCommitSplitOpen = false; }}
+  />
+{/if}
+
 {#if linePatchOpen && linePatchFile}
   <LinePatchDialog
     file={linePatchFile}

src/lib/components/AiCommitSplitDialog.svelte

@@ -0,0 +1,83 @@
+<script lang="ts">
+  import { GitCommitHorizontal, LoaderCircle, Sparkles, X } from "@lucide/svelte";
+  import type { AiCommitPlan } from "../types";
+
+  interface Props {
+    plan: AiCommitPlan;
+    isApplying: boolean;
+    onApply: (plan: AiCommitPlan) => void;
+    onClose: () => void;
+  }
+
+  let { plan, isApplying = false, onApply, onClose }: Props = $props();
+  let draft = $state<AiCommitPlan>({ summary: "", groups: [] });
+  $effect.pre(() => {
+    if (draft.groups.length === 0) draft = structuredClone(plan);
+  });
+  let valid = $derived(draft.groups.length > 1 && draft.groups.every((group) => group.message.trim() && group.files.length));
+
+  function setMessage(index: number, message: string) {
+    draft.groups[index].message = message;
+  }
+
+  function moveFile(file: string, from: number, to: number) {
+    if (from === to) return;
+    draft.groups[from].files = draft.groups[from].files.filter((path) => path !== file);
+    draft.groups[to].files = [...draft.groups[to].files, file];
+  }
+</script>
+
+<svelte:window onkeydown={(event) => { if (event.key === "Escape" && !isApplying) onClose(); }} />
+
+<div class="dialog-backdrop" role="presentation">
+  <div class="dialog split-dialog" role="dialog" aria-modal="true" aria-label="AI commit split">
+    <header class="dialog-header">
+      <div><span class="eyebrow">Staged changes</span><h2>Split into logical commits</h2></div>
+      <button class="dialog-close" type="button" onclick={onClose} disabled={isApplying} aria-label="Close"><X size={18} /></button>
+    </header>
+    <div class="split-intro"><Sparkles size={18} /><p>{draft.summary}</p></div>
+    <div class="split-groups">
+      {#each draft.groups as group, groupIndex}
+        <article class:empty={group.files.length === 0}>
+          <header><GitCommitHorizontal size={17} /><strong>Commit {groupIndex + 1}</strong><span>{group.files.length} files</span></header>
+          <label>Commit message<input value={group.message} oninput={(event) => setMessage(groupIndex, event.currentTarget.value)} disabled={isApplying} /></label>
+          {#if group.reason}<p>{group.reason}</p>{/if}
+          <div class="split-files">
+            {#each group.files as file}
+              <div><code>{file}</code>
+                <select value={groupIndex} onchange={(event) => moveFile(file, groupIndex, Number(event.currentTarget.value))} disabled={isApplying}>
+                  {#each draft.groups as _, target}<option value={target}>Commit {target + 1}</option>{/each}
+                </select>
+              </div>
+            {/each}
+          </div>
+        </article>
+      {/each}
+    </div>
+    <footer class="dialog-footer">
+      <p>Files with staged and unstaged edits are excluded for safety. Commits are created in this order.</p>
+      <div><button class="btn-secondary" type="button" onclick={onClose} disabled={isApplying}>Cancel</button>
+        <button class="btn-primary" type="button" onclick={() => onApply(structuredClone(draft))} disabled={!valid || isApplying}>
+          {#if isApplying}<LoaderCircle class="spin" size={14} />{/if}Create {draft.groups.length} commits
+        </button></div>
+    </footer>
+  </div>
+</div>
+
+<style>
+  .split-dialog{width:min(820px,calc(100vw - 32px));max-height:min(820px,calc(100vh - 32px));display:flex;flex-direction:column}
+  .split-intro{display:flex;gap:10px;align-items:flex-start;padding:14px 18px;border-bottom:1px solid var(--color-border-subtle);color:var(--color-ink-muted)}
+  .split-intro p{margin:0;line-height:1.5}
+  .split-groups{display:grid;gap:10px;padding:14px 18px;overflow:auto}
+  article{display:grid;gap:10px;padding:13px;border:1px solid var(--color-border-subtle);border-radius:9px;background:var(--color-surface-raised)}
+  article.empty{border-color:#d88a45}
+  article>header{display:flex;align-items:center;gap:8px;color:var(--color-ink)}
+  article>header span{margin-left:auto;color:var(--color-ink-faint);font-size:11px}
+  label{display:grid;gap:5px;color:var(--color-ink-faint);font-size:10px;font-weight:800;text-transform:uppercase}
+  input{height:34px;padding:0 10px;border:1px solid var(--color-border);border-radius:6px;background:var(--color-surface);color:var(--color-ink);font-family:var(--font-mono)}
+  article>p{margin:0;color:var(--color-ink-muted);font-size:12px;line-height:1.45}
+  .split-files{display:grid;gap:5px}
+  .split-files>div{display:flex;align-items:center;gap:10px;padding:6px 8px;border-radius:6px;background:var(--color-surface)}
+  code{min-width:0;flex:1;overflow:hidden;text-overflow:ellipsis;color:var(--color-ink-muted);font-size:11px;white-space:nowrap}
+  select{height:28px;border:1px solid var(--color-border-subtle);border-radius:5px;background:var(--color-surface-raised);color:var(--color-ink);font-size:11px}
+</style>

src/lib/components/CommitPanel.svelte

@@ -1,5 +1,5 @@
 <script lang="ts">
-  import { Check, LoaderCircle, RotateCcw, Settings, ShieldCheck, Sparkles } from "@lucide/svelte";
+  import { Check, GitCommitHorizontal, LoaderCircle, RotateCcw, Settings, ShieldCheck, Sparkles } from "@lucide/svelte";
   import type { CommitAiPhase, CommitAiProvider } from "../types";
 
   interface Props {
@@ -14,12 +14,14 @@
     commitAiPhase: CommitAiPhase;
     commitAiGenerating: boolean;
     commitAiReviewing: boolean;
+    commitAiSplitting: boolean;
     canAmend: boolean;
     amendMode: boolean;
     onCommit: () => void;
     onCommitMessageChange: (msg: string) => void;
     onGenerateCommitMessage: () => void;
     onReviewStaged: () => void;
+    onSplitStaged: () => void;
     onOpenAiSettings: () => void;
     onToggleAmend: (checked: boolean) => void;
     onUndoLastCommit: () => void;
@@ -37,12 +39,14 @@
     commitAiPhase = "idle",
     commitAiGenerating = false,
     commitAiReviewing = false,
+    commitAiSplitting = false,
     canAmend = false,
     amendMode = false,
     onCommit = () => {},
     onCommitMessageChange = () => {},
     onGenerateCommitMessage = () => {},
     onReviewStaged = () => {},
+    onSplitStaged = () => {},
     onOpenAiSettings = () => {},
     onToggleAmend = () => {},
     onUndoLastCommit = () => {},
@@ -70,6 +74,7 @@
     (commitAiProvider !== "local" || commitAiPhase === "ready"),
   );
   let canReview = $derived(canGenerate && commitAiProvider !== "local");
+  let canSplit = $derived(canReview && stagedCount > 1 && !commitAiSplitting);
 </script>
 
 <section class="panel commit-panel" aria-label="Commit">
@@ -80,6 +85,16 @@
     </div>
     <div class="commit-head-actions">
       <span class="pill pill-count">{stagedCount} staged</span>
+      <button
+        class="commit-review-button"
+        type="button"
+        onclick={onSplitStaged}
+        disabled={!canSplit}
+        title={commitAiProvider === "local" ? "Commit splitting currently requires an API provider" : "Suggest logical commits for the staged files"}
+      >
+        {#if commitAiSplitting}<LoaderCircle class="spin" size={14} aria-hidden="true" />{:else}<GitCommitHorizontal size={14} aria-hidden="true" />{/if}
+        Split
+      </button>
       <button
         class="commit-review-button"
         type="button"

src/lib/git.ts

@@ -2,6 +2,7 @@ import { tracedInvoke as invoke } from "./telemetry";
 
 import type {
   AiReviewResult,
+  AiCommitPlan,
   CommitAiLocalProfile,
   CommitAiProvider,
   CommitAiStatus,
@@ -322,6 +323,16 @@ export function commitAiReview(path: string, options: CommitAiGenerateOptions):
   });
 }
 
+export function commitAiSplit(path: string, options: CommitAiGenerateOptions): Promise<AiCommitPlan> {
+  return invoke<AiCommitPlan>("commit_ai_split", {
+    path,
+    provider: options.provider,
+    model: options.model,
+    apiKey: options.apiKey,
+    baseUrl: options.baseUrl,
+  });
+}
+
 export function pull(path: string, username?: string, password?: string, strategy: PullStrategy = "merge", remote?: string, branch?: string): Promise<GitStatus> {
   return invoke<GitStatus>("pull", { path, username: username ?? null, password: password ?? null, strategy, remote: remote || null, branch: branch || null });
 }

src/lib/types.ts

@@ -37,6 +37,17 @@ export interface AiReviewResult {
   findings: AiReviewFinding[];
 }
 
+export interface AiCommitGroup {
+  message: string;
+  reason: string;
+  files: string[];
+}
+
+export interface AiCommitPlan {
+  summary: string;
+  groups: AiCommitGroup[];
+}
+
 export interface LocalModelOption {
   id: string;
   label: string;