feat: add configurable model for git text generation

apps/server/src/git/Layers/CodexTextGeneration.ts

@@ -3,6 +3,7 @@ import { randomUUID } from "node:crypto";
 import { Effect, FileSystem, Layer, Option, Path, Schema, Stream } from "effect";
 import { ChildProcess, ChildProcessSpawner } from "effect/unstable/process";
 
+import { DEFAULT_GIT_TEXT_GENERATION_MODEL } from "@t3tools/contracts";
 import { sanitizeBranchFragment, sanitizeFeatureBranchName } from "@t3tools/shared/git";
 
 import { resolveAttachmentPath } from "../../attachmentStore.ts";
@@ -17,7 +18,6 @@ import {
   TextGeneration,
 } from "../Services/TextGeneration.ts";
 
-const CODEX_MODEL = "gpt-5.3-codex";
 const CODEX_REASONING_EFFORT = "low";
 const CODEX_TIMEOUT_MS = 180_000;
 
@@ -187,13 +187,15 @@ const makeCodexTextGeneration = Effect.gen(function* () {
     outputSchemaJson,
     imagePaths = [],
     cleanupPaths = [],
+    model,
   }: {
     operation: "generateCommitMessage" | "generatePrContent" | "generateBranchName";
     cwd: string;
     prompt: string;
     outputSchemaJson: S;
     imagePaths?: ReadonlyArray<string>;
     cleanupPaths?: ReadonlyArray<string>;
+    model?: string;
   }): Effect.Effect<S["Type"], TextGenerationError, S["DecodingServices"]> =>
     Effect.gen(function* () {
       const schemaPath = yield* writeTempFile(
@@ -212,7 +214,7 @@ const makeCodexTextGeneration = Effect.gen(function* () {
             "-s",
             "read-only",
             "--model",
-            CODEX_MODEL,
+            model ?? DEFAULT_GIT_TEXT_GENERATION_MODEL,
             "--config",
             `model_reasoning_effort="${CODEX_REASONING_EFFORT}"`,
             "--output-schema",
@@ -353,6 +355,7 @@ const makeCodexTextGeneration = Effect.gen(function* () {
       cwd: input.cwd,
       prompt,
       outputSchemaJson,
+      ...(input.model ? { model: input.model } : {}),
     }).pipe(
       Effect.map(
         (generated) =>
@@ -398,6 +401,7 @@ const makeCodexTextGeneration = Effect.gen(function* () {
         title: Schema.String,
         body: Schema.String,
       }),
+      ...(input.model ? { model: input.model } : {}),
     }).pipe(
       Effect.map(
         (generated) =>
@@ -449,6 +453,7 @@ const makeCodexTextGeneration = Effect.gen(function* () {
           branch: Schema.String,
         }),
         imagePaths,
+        ...(input.model ? { model: input.model } : {}),
       });
 
       return {

apps/server/src/git/Layers/GitManager.ts

@@ -639,6 +639,7 @@ export const makeGitManager = Effect.gen(function* () {
     /** When true, also produce a semantic feature branch name. */
     includeBranch?: boolean;
     filePaths?: readonly string[];
+    model?: string;
   }) =>
     Effect.gen(function* () {
       const context = yield* gitCore.prepareCommitContext(input.cwd, input.filePaths);
@@ -665,6 +666,7 @@ export const makeGitManager = Effect.gen(function* () {
           stagedSummary: limitContext(context.stagedSummary, 8_000),
           stagedPatch: limitContext(context.stagedPatch, 50_000),
           ...(input.includeBranch ? { includeBranch: true } : {}),
+          ...(input.model ? { model: input.model } : {}),
         })
         .pipe(Effect.map((result) => sanitizeCommitMessage(result)));
 
@@ -682,6 +684,7 @@ export const makeGitManager = Effect.gen(function* () {
     commitMessage?: string,
     preResolvedSuggestion?: CommitAndBranchSuggestion,
     filePaths?: readonly string[],
+    model?: string,
   ) =>
     Effect.gen(function* () {
       const suggestion =
@@ -691,6 +694,7 @@ export const makeGitManager = Effect.gen(function* () {
           branch,
           ...(commitMessage ? { commitMessage } : {}),
           ...(filePaths ? { filePaths } : {}),
+          ...(model ? { model } : {}),
         }));
       if (!suggestion) {
         return { status: "skipped_no_changes" as const };
@@ -704,7 +708,7 @@ export const makeGitManager = Effect.gen(function* () {
       };
     });
 
-  const runPrStep = (cwd: string, fallbackBranch: string | null) =>
+  const runPrStep = (cwd: string, fallbackBranch: string | null, model?: string) =>
     Effect.gen(function* () {
       const details = yield* gitCore.statusDetails(cwd);
       const branch = details.branch ?? fallbackBranch;
@@ -748,6 +752,7 @@ export const makeGitManager = Effect.gen(function* () {
         commitSummary: limitContext(rangeContext.commitSummary, 20_000),
         diffSummary: limitContext(rangeContext.diffSummary, 20_000),
         diffPatch: limitContext(rangeContext.diffPatch, 60_000),
+        ...(model ? { model } : {}),
       });
 
       const bodyFile = path.join(tempDir, `t3code-pr-body-${process.pid}-${randomUUID()}.md`);
@@ -972,6 +977,7 @@ export const makeGitManager = Effect.gen(function* () {
     branch: string | null,
     commitMessage?: string,
     filePaths?: readonly string[],
+    model?: string,
   ) =>
     Effect.gen(function* () {
       const suggestion = yield* resolveCommitAndBranchSuggestion({
@@ -980,6 +986,7 @@ export const makeGitManager = Effect.gen(function* () {
         ...(commitMessage ? { commitMessage } : {}),
         ...(filePaths ? { filePaths } : {}),
         includeBranch: true,
+        ...(model ? { model } : {}),
       });
       if (!suggestion) {
         return yield* gitManagerError(
@@ -1028,6 +1035,7 @@ export const makeGitManager = Effect.gen(function* () {
           initialStatus.branch,
           input.commitMessage,
           input.filePaths,
+          input.textGenerationModel,
         );
         branchStep = result.branchStep;
         commitMessageForStep = result.resolvedCommitMessage;
@@ -1044,14 +1052,15 @@ export const makeGitManager = Effect.gen(function* () {
         commitMessageForStep,
         preResolvedCommitSuggestion,
         input.filePaths,
+        input.textGenerationModel,
       );
 
       const push = wantsPush
         ? yield* gitCore.pushCurrentBranch(input.cwd, currentBranch)
         : { status: "skipped_not_requested" as const };
 
       const pr = wantsPr
-        ? yield* runPrStep(input.cwd, currentBranch)
+        ? yield* runPrStep(input.cwd, currentBranch, input.textGenerationModel)
         : { status: "skipped_not_requested" as const };
 
       return {

apps/server/src/git/Services/TextGeneration.ts

@@ -19,6 +19,8 @@ export interface CommitMessageGenerationInput {
   stagedPatch: string;
   /** When true, the model also returns a semantic branch name for the change. */
   includeBranch?: boolean;
+  /** Model to use for generation. Defaults to gpt-5.4-mini if not specified. */
+  model?: string;
 }
 
 export interface CommitMessageGenerationResult {
@@ -35,6 +37,8 @@ export interface PrContentGenerationInput {
   commitSummary: string;
   diffSummary: string;
   diffPatch: string;
+  /** Model to use for generation. Defaults to gpt-5.4-mini if not specified. */
+  model?: string;
 }
 
 export interface PrContentGenerationResult {
@@ -46,6 +50,8 @@ export interface BranchNameGenerationInput {
   cwd: string;
   message: string;
   attachments?: ReadonlyArray<ChatAttachment> | undefined;
+  /** Model to use for generation. Defaults to gpt-5.4-mini if not specified. */
+  model?: string;
 }
 
 export interface BranchNameGenerationResult {

apps/server/src/orchestration/Layers/ProviderCommandReactor.ts

@@ -1,6 +1,7 @@
 import {
   type ChatAttachment,
   CommandId,
+  DEFAULT_GIT_TEXT_GENERATION_MODEL,
   EventId,
   type OrchestrationEvent,
   type ProviderModelOptions,
@@ -391,6 +392,7 @@ const make = Effect.gen(function* () {
         cwd,
         message: input.messageText,
         ...(attachments.length > 0 ? { attachments } : {}),
+        model: DEFAULT_GIT_TEXT_GENERATION_MODEL,
       })
       .pipe(
         Effect.catch((error) =>

apps/web/src/appSettings.test.ts

@@ -28,6 +28,7 @@ describe("getAppModelOptions", () => {
 
     expect(options.map((option) => option.slug)).toEqual([
       "gpt-5.4",
+      "gpt-5.4-mini",
       "gpt-5.3-codex",
       "gpt-5.3-codex-spark",
       "gpt-5.2-codex",

apps/web/src/appSettings.ts

@@ -1,6 +1,6 @@
 import { useCallback } from "react";
 import { Option, Schema } from "effect";
-import { type ProviderKind } from "@t3tools/contracts";
+import { TrimmedNonEmptyString, type ProviderKind } from "@t3tools/contracts";
 import { getDefaultModel, getModelOptions, normalizeModelSlug } from "@t3tools/shared/model";
 import { useLocalStorage } from "./hooks/useLocalStorage";
 
@@ -34,6 +34,7 @@ const AppSettingsSchema = Schema.Struct({
   customCodexModels: Schema.Array(Schema.String).pipe(
     Schema.withConstructorDefault(() => Option.some([])),
   ),
+  textGenerationModel: Schema.optional(TrimmedNonEmptyString),
 });
 export type AppSettings = typeof AppSettingsSchema.Type;
 export interface AppModelOption {

apps/web/src/components/GitActionsControl.tsx

@@ -15,6 +15,7 @@ import {
   resolveQuickAction,
   summarizeGitResult,
 } from "./GitActionsControl.logic";
+import { useAppSettings } from "~/appSettings";
 import { Button } from "~/components/ui/button";
 import { Checkbox } from "~/components/ui/checkbox";
 import {
@@ -154,6 +155,7 @@ function GitQuickActionIcon({ quickAction }: { quickAction: GitQuickAction }) {
 }
 
 export default function GitActionsControl({ gitCwd, activeThreadId }: GitActionsControlProps) {
+  const { settings } = useAppSettings();
   const threadToastData = useMemo(
     () => (activeThreadId ? { threadId: activeThreadId } : undefined),
     [activeThreadId],
@@ -191,7 +193,11 @@ export default function GitActionsControl({ gitCwd, activeThreadId }: GitActions
   const initMutation = useMutation(gitInitMutationOptions({ cwd: gitCwd, queryClient }));
 
   const runImmediateGitActionMutation = useMutation(
-    gitRunStackedActionMutationOptions({ cwd: gitCwd, queryClient }),
+    gitRunStackedActionMutationOptions({
+      cwd: gitCwd,
+      queryClient,
+      model: settings.textGenerationModel ?? null,
+    }),
   );
   const pullMutation = useMutation(gitPullMutationOptions({ cwd: gitCwd, queryClient }));
 

apps/web/src/lib/gitReactQuery.ts

@@ -112,6 +112,7 @@ export function gitCheckoutMutationOptions(input: {
 export function gitRunStackedActionMutationOptions(input: {
   cwd: string | null;
   queryClient: QueryClient;
+  model?: string | null;
 }) {
   return mutationOptions({
     mutationKey: gitMutationKeys.runStackedAction(input.cwd),
@@ -134,6 +135,7 @@ export function gitRunStackedActionMutationOptions(input: {
         ...(commitMessage ? { commitMessage } : {}),
         ...(featureBranch ? { featureBranch } : {}),
         ...(filePaths ? { filePaths } : {}),
+        ...(input.model ? { model: input.model } : {}),
       });
     },
     onSettled: async () => {

apps/web/src/routes/_chat.settings.tsx

@@ -1,9 +1,9 @@
 import { createFileRoute } from "@tanstack/react-router";
 import { useQuery } from "@tanstack/react-query";
 import { useCallback, useState } from "react";
-import { type ProviderKind } from "@t3tools/contracts";
+import { type ProviderKind, DEFAULT_GIT_TEXT_GENERATION_MODEL } from "@t3tools/contracts";
 import { getModelOptions, normalizeModelSlug } from "@t3tools/shared/model";
-import { MAX_CUSTOM_MODEL_LENGTH, useAppSettings } from "../appSettings";
+import { getAppModelOptions, MAX_CUSTOM_MODEL_LENGTH, useAppSettings } from "../appSettings";
 import { resolveAndPersistPreferredEditor } from "../editorPreferences";
 import { isElectron } from "../env";
 import { useTheme } from "../hooks/useTheme";
@@ -112,6 +112,17 @@ function SettingsRouteView() {
   const keybindingsConfigPath = serverConfigQuery.data?.keybindingsConfigPath ?? null;
   const availableEditors = serverConfigQuery.data?.availableEditors;
 
+  const gitTextGenerationModelOptions = getAppModelOptions(
+    "codex",
+    settings.customCodexModels,
+    settings.textGenerationModel,
+  );
+  const selectedGitTextGenerationModelLabel =
+    gitTextGenerationModelOptions.find(
+      (option) =>
+        option.slug === (settings.textGenerationModel ?? DEFAULT_GIT_TEXT_GENERATION_MODEL),
+    )?.name ?? settings.textGenerationModel;
+
   const openKeybindingsFile = useCallback(() => {
     if (!keybindingsConfigPath) return;
     setOpenKeybindingsError(null);
@@ -502,6 +513,65 @@ function SettingsRouteView() {
               </div>
             </section>
 
+            <section className="rounded-2xl border border-border bg-card p-5">
+              <div className="mb-4">
+                <h2 className="text-sm font-medium text-foreground">Git</h2>
+                <p className="mt-1 text-xs text-muted-foreground">
+                  Configure the model used for generating commit messages, PR titles, and branch
+                  names.
+                </p>
+              </div>
+
+              <div className="flex flex-col gap-4 rounded-lg border border-border bg-background px-3 py-3 sm:flex-row sm:items-center sm:justify-between">
+                <div className="min-w-0 flex-1">
+                  <p className="text-sm font-medium text-foreground">Text generation model</p>
+                  <p className="text-xs text-muted-foreground">
+                    Model used for auto-generated git content.
+                  </p>
+                </div>
+                <Select
+                  value={settings.textGenerationModel ?? DEFAULT_GIT_TEXT_GENERATION_MODEL}
+                  onValueChange={(value) => {
+                    if (value) {
+                      updateSettings({
+                        textGenerationModel: value,
+                      });
+                    }
+                  }}
+                >
+                  <SelectTrigger
+                    className="w-full shrink-0 sm:w-48"
+                    aria-label="Git text generation model"
+                  >
+                    <SelectValue>{selectedGitTextGenerationModelLabel}</SelectValue>
+                  </SelectTrigger>
+                  <SelectPopup align="end">
+                    {gitTextGenerationModelOptions.map((option) => (
+                      <SelectItem key={option.slug} value={option.slug}>
+                        {option.name}
+                      </SelectItem>
+                    ))}
+                  </SelectPopup>
+                </Select>
+              </div>
+
+              {settings.textGenerationModel !== defaults.textGenerationModel ? (
+                <div className="mt-3 flex justify-end">
+                  <Button
+                    size="xs"
+                    variant="outline"
+                    onClick={() =>
+                      updateSettings({
+                        textGenerationModel: defaults.textGenerationModel,
+                      })
+                    }
+                  >
+                    Restore default
+                  </Button>
+                </div>
+              ) : null}
+            </section>
+
             <section className="rounded-2xl border border-border bg-card p-5">
               <div className="mb-4">
                 <h2 className="text-sm font-medium text-foreground">Threads</h2>

packages/contracts/src/git.ts

@@ -1,5 +1,6 @@
-import { Schema } from "effect";
+import { Option, Schema } from "effect";
 import { NonNegativeInt, PositiveInt, TrimmedNonEmptyString } from "./baseSchemas";
+import { DEFAULT_GIT_TEXT_GENERATION_MODEL } from "./model";
 
 const TrimmedNonEmptyStringSchema = TrimmedNonEmptyString;
 
@@ -64,6 +65,9 @@ export const GitRunStackedActionInput = Schema.Struct({
   filePaths: Schema.optional(
     Schema.Array(TrimmedNonEmptyStringSchema).check(Schema.isMinLength(1)),
   ),
+  textGenerationModel: Schema.optional(TrimmedNonEmptyStringSchema).pipe(
+    Schema.withConstructorDefault(() => Option.some(DEFAULT_GIT_TEXT_GENERATION_MODEL)),
+  ),
 });
 export type GitRunStackedActionInput = typeof GitRunStackedActionInput.Type;
 

packages/contracts/src/model.ts

@@ -23,6 +23,7 @@ type ModelOption = {
 export const MODEL_OPTIONS_BY_PROVIDER = {
   codex: [
     { slug: "gpt-5.4", name: "GPT-5.4" },
+    { slug: "gpt-5.4-mini", name: "GPT-5.4 Mini" },
     { slug: "gpt-5.3-codex", name: "GPT-5.3 Codex" },
     { slug: "gpt-5.3-codex-spark", name: "GPT-5.3 Codex Spark" },
     { slug: "gpt-5.2-codex", name: "GPT-5.2 Codex" },
@@ -38,6 +39,8 @@ export const DEFAULT_MODEL_BY_PROVIDER = {
   codex: "gpt-5.4",
 } as const satisfies Record<ProviderKind, ModelSlug>;
 
+export const DEFAULT_GIT_TEXT_GENERATION_MODEL = "gpt-5.4-mini" as const;
+
 export const MODEL_SLUG_ALIASES_BY_PROVIDER = {
   codex: {
     "5.4": "gpt-5.4",