diff --git a/readme.hints.md b/readme.hints.md
index 291ed98..c0fb540 100644
--- a/readme.hints.md
+++ b/readme.hints.md
@@ -193,12 +193,22 @@ gitzone format
 # Read-only JSON plan
 gitzone format plan --json
 
+# CI-friendly check, exits non-zero when changes or validator errors remain
+gitzone format check
+
 # Dry run to preview changes
 gitzone format --dry-run
 
+# Limit formatter modules
+gitzone format --only prettier,packagejson
+gitzone format --skip license
+
 # Non-interactive apply
 gitzone format --write --yes
 
+# Deterministic format first, opencode for remaining issues
+gitzone format fix
+
 # Plan only (no execution)
 gitzone format --plan-only
 
diff --git a/readme.md b/readme.md
index ad7daa7..7b83484 100644
--- a/readme.md
+++ b/readme.md
@@ -309,15 +309,26 @@ gitzone format
 # Emit a machine-readable plan
 gitzone format plan --json
 
+# Fail when formatting changes or validator errors remain
+gitzone format check
+
+# Run a subset of formatters
+gitzone format --only prettier,packagejson
+
 # Apply changes
 gitzone format --write
 
 # Apply without prompt
 gitzone format --write --yes
+
+# Apply deterministic fixes, then use opencode for remaining issues
+gitzone format fix
 ```
 
 Formatters include cleanup, smartconfig normalization, dependency license checks, package metadata normalization, template updates, `.gitignore`, TypeScript config, Prettier, README existence checks, and configured copy operations.
 
+`gitzone format fix` intentionally lives outside the default format path. Normal format runs stay deterministic; the fix command uses opencode only after deterministic formatters have done what they can.
+
 ## Development Services
 
 `gitzone services` manages local Docker-backed services for development projects.
diff --git a/ts/gitzone.cli.ts b/ts/gitzone.cli.ts
index d6fa53b..3d13972 100644
--- a/ts/gitzone.cli.ts
+++ b/ts/gitzone.cli.ts
@@ -1,13 +1,107 @@
 import * as plugins from "./plugins.js";
 import * as paths from "./paths.js";
-import { GitzoneConfig } from "./classes.gitzoneconfig.js";
-import { getRawCliMode } from "./helpers.climode.js";
+import {
+  getProcessUserArgv,
+  getRawCliMode,
+  parseCliArgv,
+} from "./helpers.climode.js";
 import { commitinfo } from "./00_commitinfo_data.js";
 
-const gitzoneSmartcli = new plugins.smartcli.Smartcli();
+const runParsedCommand = async (argvArg: any): Promise<void> => {
+  const command = argvArg._?.[0];
+
+  switch (command) {
+    case undefined:
+    case "help": {
+      const modStandard = await import("./mod_standard/index.js");
+      await modStandard.run(argvArg);
+      break;
+    }
+    case "commit": {
+      const modCommit = await import("./mod_commit/index.js");
+      await modCommit.run(argvArg);
+      break;
+    }
+    case "release": {
+      const modRelease = await import("./mod_release/index.js");
+      await modRelease.run(argvArg);
+      break;
+    }
+    case "deprecate": {
+      const modDeprecate = await import("./mod_deprecate/index.js");
+      await modDeprecate.run();
+      break;
+    }
+    case "docker": {
+      const modDocker = await import("./mod_docker/index.js");
+      await modDocker.run(argvArg);
+      break;
+    }
+    case "format": {
+      const modFormat = await import("./mod_format/index.js");
+      await modFormat.run({
+        ...argvArg,
+        write: argvArg.write || argvArg.w,
+        dryRun: argvArg["dry-run"],
+        yes: argvArg.yes || argvArg.y,
+        planOnly: argvArg["plan-only"] || argvArg.planOnly,
+        savePlan: argvArg["save-plan"] || argvArg.savePlan,
+        fromPlan: argvArg["from-plan"] || argvArg.fromPlan,
+        detailed: argvArg.detailed,
+        interactive: argvArg.interactive !== false,
+        verbose: argvArg.verbose,
+        diff: argvArg.diff,
+      });
+      break;
+    }
+    case "meta": {
+      const modMeta = await import("./mod_meta/index.js");
+      await modMeta.run(argvArg);
+      break;
+    }
+    case "open": {
+      const modOpen = await import("./mod_open/index.js");
+      await modOpen.run(argvArg);
+      break;
+    }
+    case "template": {
+      const modTemplate = await import("./mod_template/index.js");
+      await modTemplate.run(argvArg);
+      break;
+    }
+    case "start": {
+      const modStart = await import("./mod_start/index.js");
+      await modStart.run(argvArg);
+      break;
+    }
+    case "helpers": {
+      const modHelpers = await import("./mod_helpers/index.js");
+      await modHelpers.run(argvArg);
+      break;
+    }
+    case "tools": {
+      const modTools = await import("./mod_tools/index.js");
+      await modTools.run(argvArg);
+      break;
+    }
+    case "config": {
+      const modConfig = await import("./mod_config/index.js");
+      await modConfig.run(argvArg);
+      break;
+    }
+    case "services": {
+      const modServices = await import("./mod_services/index.js");
+      await modServices.run(argvArg);
+      break;
+    }
+    default: {
+      const modStandard = await import("./mod_standard/index.js");
+      await modStandard.run(argvArg);
+    }
+  }
+};
 
 export let run = async () => {
-  const done = plugins.smartpromise.defer();
   const rawCliMode = await getRawCliMode();
 
   // get packageInfo
@@ -34,144 +128,10 @@ export let run = async () => {
   if (rawCliMode.output === "human") {
     console.log("---------------------------------------------");
   }
-  gitzoneSmartcli.addVersion(packageVersion);
-
-  // ======> Standard task <======
-
-  /**
-   * standard task
-   */
-  gitzoneSmartcli.standardCommand().subscribe(async (argvArg) => {
-    const modStandard = await import("./mod_standard/index.js");
-    await modStandard.run(argvArg);
-  });
-
-  gitzoneSmartcli.addCommand("help").subscribe(async (argvArg) => {
-    const modStandard = await import("./mod_standard/index.js");
-    await modStandard.run(argvArg);
-  });
-
-  // ======> Specific tasks <======
-
-  /**
-   * commit something
-   */
-  gitzoneSmartcli.addCommand("commit").subscribe(async (argvArg) => {
-    const modCommit = await import("./mod_commit/index.js");
-    await modCommit.run(argvArg);
-  });
-
-  /**
-   * create a release from pending changelog entries
-   */
-  gitzoneSmartcli.addCommand("release").subscribe(async (argvArg) => {
-    const modRelease = await import("./mod_release/index.js");
-    await modRelease.run(argvArg);
-  });
-
-  /**
-   * deprecate a package on npm
-   */
-  gitzoneSmartcli.addCommand("deprecate").subscribe(async (argvArg) => {
-    const modDeprecate = await import("./mod_deprecate/index.js");
-    await modDeprecate.run();
-  });
-
-  /**
-   * docker
-   */
-  gitzoneSmartcli.addCommand("docker").subscribe(async (argvArg) => {
-    const modDocker = await import("./mod_docker/index.js");
-    await modDocker.run(argvArg);
-  });
-
-  /**
-   * Update all files that comply with the gitzone standard
-   */
-  gitzoneSmartcli.addCommand("format").subscribe(async (argvArg) => {
-    const config = GitzoneConfig.fromCwd();
-    const modFormat = await import("./mod_format/index.js");
-
-    // Handle format with options
-    // Default is dry-mode, use --write/-w to apply changes
-    await modFormat.run({
-      ...argvArg,
-      write: argvArg.write || argvArg.w,
-      dryRun: argvArg["dry-run"],
-      yes: argvArg.yes,
-      planOnly: argvArg["plan-only"],
-      savePlan: argvArg["save-plan"],
-      fromPlan: argvArg["from-plan"],
-      detailed: argvArg.detailed,
-      interactive: argvArg.interactive !== false,
-      verbose: argvArg.verbose,
-      diff: argvArg.diff,
-    });
-  });
-
-  /**
-   * run meta commands
-   */
-  gitzoneSmartcli.addCommand("meta").subscribe(async (argvArg) => {
-    const config = GitzoneConfig.fromCwd();
-    const modMeta = await import("./mod_meta/index.js");
-    modMeta.run(argvArg);
-  });
-
-  /**
-   * open assets
-   */
-  gitzoneSmartcli.addCommand("open").subscribe(async (argvArg) => {
-    const modOpen = await import("./mod_open/index.js");
-    modOpen.run(argvArg);
-  });
-
-  /**
-   * add a readme to a project
-   */
-  gitzoneSmartcli.addCommand("template").subscribe(async (argvArg) => {
-    const modTemplate = await import("./mod_template/index.js");
-    modTemplate.run(argvArg);
-  });
-
-  /**
-   * start working on a project
-   */
-  gitzoneSmartcli.addCommand("start").subscribe(async (argvArg) => {
-    const modTemplate = await import("./mod_start/index.js");
-    modTemplate.run(argvArg);
-  });
-
-  gitzoneSmartcli.addCommand("helpers").subscribe(async (argvArg) => {
-    const modHelpers = await import("./mod_helpers/index.js");
-    modHelpers.run(argvArg);
-  });
-
-  /**
-   * manage the global @git.zone toolchain
-   */
-  gitzoneSmartcli.addCommand("tools").subscribe(async (argvArg) => {
-    const modTools = await import("./mod_tools/index.js");
-    await modTools.run(argvArg);
-  });
-
-  /**
-   * manage release configuration
-   */
-  gitzoneSmartcli.addCommand("config").subscribe(async (argvArg) => {
-    const modConfig = await import("./mod_config/index.js");
-    await modConfig.run(argvArg);
-  });
-
-  /**
-   * manage development services (MongoDB, S3/MinIO)
-   */
-  gitzoneSmartcli.addCommand("services").subscribe(async (argvArg) => {
-    const modServices = await import("./mod_services/index.js");
-    await modServices.run(argvArg);
-  });
-
-  // start parsing of the cli
-  gitzoneSmartcli.startParse();
-  return await done.promise;
+  const argvArg = parseCliArgv(getProcessUserArgv());
+  if (argvArg.v || argvArg.version) {
+    console.log(packageVersion);
+    return;
+  }
+  await runParsedCommand(argvArg);
 };
diff --git a/ts/helpers.climode.ts b/ts/helpers.climode.ts
index bd60a02..3a84610 100644
--- a/ts/helpers.climode.ts
+++ b/ts/helpers.climode.ts
@@ -88,6 +88,41 @@ const parseRawArgv = (argv: string[]): TArgSource => {
   return parsedArgv;
 };
 
+export const parseCliArgv = parseRawArgv;
+
+export const getProcessUserArgv = (): string[] => {
+  const rawArgv = process.argv;
+  const argv0Base = (rawArgv[0] || "").split(/[\\/]/).pop()?.toLowerCase();
+  const runtimeNames = new Set([
+    "node",
+    "node.exe",
+    "nodejs",
+    "nodejs.exe",
+    "bun",
+    "bun.exe",
+    "deno",
+    "deno.exe",
+    "tsx",
+    "tsx.exe",
+    "ts-node",
+    "ts-node.exe",
+  ]);
+
+  if (!runtimeNames.has(argv0Base || "")) {
+    return rawArgv.slice();
+  }
+
+  const firstUserArg = rawArgv[1] || "";
+  const firstUserArgLooksLikeScript =
+    firstUserArg.includes("/") ||
+    firstUserArg.endsWith(".js") ||
+    firstUserArg.endsWith(".ts") ||
+    firstUserArg.endsWith(".mjs") ||
+    firstUserArg.endsWith(".cjs");
+
+  return rawArgv.slice(firstUserArgLooksLikeScript ? 2 : 1);
+};
+
 const normalizeOutputMode = (value: unknown): TCliOutputMode | undefined => {
   if (value === "human" || value === "plain" || value === "json") {
     return value;
@@ -171,7 +206,7 @@ export const getCliMode = async (
 
 export const getRawCliMode = async (): Promise<ICliMode> => {
   const cliConfig = await getCliModeConfig();
-  const rawArgv = parseRawArgv(process.argv.slice(2));
+  const rawArgv = parseRawArgv(getProcessUserArgv());
   return resolveCliMode(rawArgv, cliConfig);
 };
 
diff --git a/ts/mod_format/classes.baseformatter.ts b/ts/mod_format/classes.baseformatter.ts
index 3d56c7d..8e91b6e 100644
--- a/ts/mod_format/classes.baseformatter.ts
+++ b/ts/mod_format/classes.baseformatter.ts
@@ -1,6 +1,10 @@
 import * as plugins from './mod.plugins.js';
 import { FormatContext } from './classes.formatcontext.js';
-import type { IPlannedChange, ICheckResult } from './interfaces.format.js';
+import type {
+  IPlannedChange,
+  ICheckResult,
+  IFormatWarning,
+} from './interfaces.format.js';
 import { Project } from '../classes.project.js';
 import { FormatStats } from './classes.formatstats.js';
 
@@ -19,6 +23,14 @@ export abstract class BaseFormatter {
   abstract analyze(): Promise<IPlannedChange[]>;
   abstract applyChange(change: IPlannedChange): Promise<void>;
 
+  get runsWithoutChanges(): boolean {
+    return false;
+  }
+
+  async validate(): Promise<IFormatWarning[]> {
+    return [];
+  }
+
   async execute(changes: IPlannedChange[]): Promise<void> {
     const startTime = this.stats.moduleStartTime(this.name);
     this.stats.startModule(this.name);
diff --git a/ts/mod_format/classes.formatplanner.ts b/ts/mod_format/classes.formatplanner.ts
index 71a4cb0..67ed021 100644
--- a/ts/mod_format/classes.formatplanner.ts
+++ b/ts/mod_format/classes.formatplanner.ts
@@ -1,7 +1,11 @@
 import * as plugins from './mod.plugins.js';
 import { FormatContext } from './classes.formatcontext.js';
 import { BaseFormatter } from './classes.baseformatter.js';
-import type { IFormatPlan, IPlannedChange } from './interfaces.format.js';
+import type {
+  IFormatPlan,
+  IPlannedChange,
+  IFormatWarning,
+} from './interfaces.format.js';
 import { getModuleIcon } from './interfaces.format.js';
 import { logger } from '../gitzone.logging.js';
 import { DiffReporter } from './classes.diffreporter.js';
@@ -42,15 +46,21 @@ export class FormatPlanner {
               break;
           }
         }
+
+        const warnings = await module.validate();
+        plan.warnings.push(...warnings);
       } catch (error) {
+        const errorMessage = error instanceof Error ? error.message : String(error);
         plan.warnings.push({
           level: 'error',
-          message: `Failed to analyze module ${module.name}: ${error.message}`,
+          message: `Failed to analyze module ${module.name}: ${errorMessage}`,
           module: module.name,
         });
       }
     }
 
+    plan.warnings.push(...this.detectConflictingChanges(plan.changes));
+
     plan.summary.totalFiles =
       plan.summary.filesAdded +
       plan.summary.filesModified +
@@ -65,11 +75,12 @@ export class FormatPlanner {
     context: FormatContext,
   ): Promise<void> {
     const startTime = Date.now();
+    const changesByModule = this.groupChangesByModule(plan.changes);
 
     for (const module of modules) {
-      const changes = this.plannedChanges.get(module.name) || [];
+      const changes = changesByModule.get(module.name) || [];
 
-      if (changes.length > 0) {
+      if (changes.length > 0 || module.runsWithoutChanges) {
         logger.log('info', `Executing ${module.name} formatter...`);
         await module.execute(changes);
       }
@@ -138,4 +149,55 @@ export class FormatPlanner {
         return '❌';
     }
   }
+
+  private groupChangesByModule(
+    changes: IPlannedChange[],
+  ): Map<string, IPlannedChange[]> {
+    const changesByModule = new Map<string, IPlannedChange[]>();
+    for (const change of changes) {
+      const moduleChanges = changesByModule.get(change.module) || [];
+      moduleChanges.push(change);
+      changesByModule.set(change.module, moduleChanges);
+    }
+    return changesByModule;
+  }
+
+  private detectConflictingChanges(
+    changes: IPlannedChange[],
+  ): IFormatWarning[] {
+    const warnings: IFormatWarning[] = [];
+    const changesByPath = new Map<string, IPlannedChange[]>();
+
+    for (const change of changes) {
+      if (!change.path || change.path === '<various files>') {
+        continue;
+      }
+
+      const pathChanges = changesByPath.get(change.path) || [];
+      pathChanges.push(change);
+      changesByPath.set(change.path, pathChanges);
+    }
+
+    for (const [path, pathChanges] of changesByPath) {
+      const modules = [...new Set(pathChanges.map((change) => change.module))];
+      if (modules.length < 2) {
+        continue;
+      }
+
+      const hasDelete = pathChanges.some((change) => change.type === 'delete');
+      const plannedContents = pathChanges
+        .map((change) => change.content)
+        .filter((content): content is string => content !== undefined);
+      const uniqueContents = new Set(plannedContents);
+      const level = hasDelete || uniqueContents.size > 1 ? 'warning' : 'info';
+
+      warnings.push({
+        level,
+        module: 'planner',
+        message: `Multiple formatters plan changes for ${path}: ${modules.join(', ')}. They will run in formatter order.`,
+      });
+    }
+
+    return warnings;
+  }
 }
diff --git a/ts/mod_format/formatters/license.formatter.ts b/ts/mod_format/formatters/license.formatter.ts
index 8d33b82..7dc3203 100644
--- a/ts/mod_format/formatters/license.formatter.ts
+++ b/ts/mod_format/formatters/license.formatter.ts
@@ -1,5 +1,5 @@
 import { BaseFormatter } from '../classes.baseformatter.js';
-import type { IPlannedChange } from '../interfaces.format.js';
+import type { IFormatWarning, IPlannedChange } from '../interfaces.format.js';
 import * as plugins from '../mod.plugins.js';
 import * as paths from '../../paths.js';
 import { logger } from '../../gitzone.logging.js';
@@ -11,6 +11,10 @@ export class LicenseFormatter extends BaseFormatter {
     return 'license';
   }
 
+  get runsWithoutChanges(): boolean {
+    return true;
+  }
+
   async analyze(): Promise<IPlannedChange[]> {
     // License formatter only checks for incompatible licenses
     // It does not modify any files, so return empty array
@@ -18,29 +22,34 @@ export class LicenseFormatter extends BaseFormatter {
     return [];
   }
 
+  async validate(): Promise<IFormatWarning[]> {
+    const result = await this.checkLicenses();
+    if (!result || result.failingModules.length === 0) {
+      return [];
+    }
+
+    return [
+      {
+        level: 'error',
+        module: this.name,
+        message: `License check failed for ${result.failingModules.length} module(s): ${result.failingModules
+          .map((failedModule) => `${failedModule.name} (${failedModule.license})`)
+          .join(', ')}`,
+      },
+    ];
+  }
+
   async execute(changes: IPlannedChange[]): Promise<void> {
     const startTime = this.stats.moduleStartTime(this.name);
     this.stats.startModule(this.name);
 
     try {
-      // Check if node_modules exists
-      const nodeModulesPath = plugins.path.join(paths.cwd, 'node_modules');
-      const nodeModulesExists = await plugins.smartfs
-        .directory(nodeModulesPath)
-        .exists();
-
-      if (!nodeModulesExists) {
+      const licenseCheckResult = await this.checkLicenses();
+      if (!licenseCheckResult) {
         logger.log('warn', 'No node_modules found. Skipping license check');
         return;
       }
 
-      // Run license check
-      const licenseChecker = await plugins.smartlegal.createLicenseChecker();
-      const licenseCheckResult = await licenseChecker.excludeLicenseWithinPath(
-        paths.cwd,
-        INCOMPATIBLE_LICENSES,
-      );
-
       if (licenseCheckResult.failingModules.length === 0) {
         logger.log('info', 'License check passed - no incompatible licenses found');
       } else {
@@ -59,4 +68,23 @@ export class LicenseFormatter extends BaseFormatter {
   async applyChange(change: IPlannedChange): Promise<void> {
     // No file changes for license formatter
   }
+
+  private async checkLicenses(): Promise<{
+    failingModules: Array<{ name: string; license: string }>;
+  } | undefined> {
+    const nodeModulesPath = plugins.path.join(paths.cwd, 'node_modules');
+    const nodeModulesExists = await plugins.smartfs
+      .directory(nodeModulesPath)
+      .exists();
+
+    if (!nodeModulesExists) {
+      return undefined;
+    }
+
+    const licenseChecker = await plugins.smartlegal.createLicenseChecker();
+    return await licenseChecker.excludeLicenseWithinPath(
+      paths.cwd,
+      INCOMPATIBLE_LICENSES,
+    );
+  }
 }
diff --git a/ts/mod_format/formatters/prettier.formatter.ts b/ts/mod_format/formatters/prettier.formatter.ts
index 155066f..34f043c 100644
--- a/ts/mod_format/formatters/prettier.formatter.ts
+++ b/ts/mod_format/formatters/prettier.formatter.ts
@@ -56,7 +56,8 @@ export class PrettierFormatter extends BaseFormatter {
         );
         allFiles.push(...filteredFiles);
       } catch (error) {
-        logVerbose(`Skipping directory ${dir}: ${error.message}`);
+        const errorMessage = error instanceof Error ? error.message : String(error);
+        logVerbose(`Skipping directory ${dir}: ${errorMessage}`);
       }
     }
 
@@ -72,7 +73,8 @@ export class PrettierFormatter extends BaseFormatter {
         const rootLevelFiles = rootFiles.filter((f) => !f.includes('/'));
         allFiles.push(...rootLevelFiles);
       } catch (error) {
-        logVerbose(`Skipping pattern ${pattern}: ${error.message}`);
+        const errorMessage = error instanceof Error ? error.message : String(error);
+        logVerbose(`Skipping pattern ${pattern}: ${errorMessage}`);
       }
     }
 
@@ -89,20 +91,46 @@ export class PrettierFormatter extends BaseFormatter {
         }
       } catch (error) {
         // Skip files that can't be accessed
-        logVerbose(`Skipping ${file} - cannot access: ${error.message}`);
+        const errorMessage = error instanceof Error ? error.message : String(error);
+        logVerbose(`Skipping ${file} - cannot access: ${errorMessage}`);
       }
     }
 
+    const prettier = await import('prettier');
+    const prettierConfig = await this.getPrettierConfig();
+
     for (const file of validFiles) {
-      changes.push({
-        type: 'modify',
-        path: file,
-        module: this.name,
-        description: 'Format with Prettier',
-      });
+      try {
+        const fileExt = plugins.path.extname(file).toLowerCase();
+        if (!fileExt) {
+          continue;
+        }
+
+        const content = (await plugins.smartfs
+          .file(file)
+          .encoding('utf8')
+          .read()) as string;
+        const formatted = await prettier.format(content, {
+          filepath: file,
+          ...prettierConfig,
+        });
+
+        if (formatted !== content) {
+          changes.push({
+            type: 'modify',
+            path: file,
+            module: this.name,
+            description: 'Format with Prettier',
+            content: formatted,
+          });
+        }
+      } catch (error) {
+        const errorMessage = error instanceof Error ? error.message : String(error);
+        logVerbose(`Skipping Prettier analysis for ${file}: ${errorMessage}`);
+      }
     }
 
-    logger.log('info', `Found ${changes.length} files to format with Prettier`);
+    logger.log('info', `Found ${changes.length} files needing Prettier`);
     return changes;
   }
 
@@ -127,9 +155,10 @@ export class PrettierFormatter extends BaseFormatter {
           this.stats.recordFileOperation(this.name, change.type, true);
         } catch (error) {
           this.stats.recordFileOperation(this.name, change.type, false);
+          const errorMessage = error instanceof Error ? error.message : String(error);
           logger.log(
             'error',
-            `Failed to format ${change.path}: ${error.message}`,
+            `Failed to format ${change.path}: ${errorMessage}`,
           );
           // Don't throw - continue with other files
         }
@@ -192,28 +221,32 @@ export class PrettierFormatter extends BaseFormatter {
           logVerbose(`No formatting changes for ${change.path}`);
         }
       } catch (prettierError) {
+        const prettierErrorMessage = prettierError instanceof Error
+          ? prettierError.message
+          : String(prettierError);
         // Check if it's a parser error
-        if (
-          prettierError.message &&
-          prettierError.message.includes('No parser could be inferred')
-        ) {
-          logVerbose(`Skipping ${change.path} - ${prettierError.message}`);
+        if (prettierErrorMessage.includes('No parser could be inferred')) {
+          logVerbose(`Skipping ${change.path} - ${prettierErrorMessage}`);
           return; // Skip this file silently
         }
         throw prettierError;
       }
     } catch (error) {
+      const errorMessage = error instanceof Error ? error.message : String(error);
+      const errorStack = error instanceof Error ? error.stack : undefined;
       // Log the full error stack for debugging mkdir issues
-      if (error.message && error.message.includes('mkdir')) {
+      if (errorMessage.includes('mkdir')) {
         logger.log(
           'error',
-          `Failed to format ${change.path}: ${error.message}`,
+          `Failed to format ${change.path}: ${errorMessage}`,
         );
-        logger.log('error', `Error stack: ${error.stack}`);
+        if (errorStack) {
+          logger.log('error', `Error stack: ${errorStack}`);
+        }
       } else {
         logger.log(
           'error',
-          `Failed to format ${change.path}: ${error.message}`,
+          `Failed to format ${change.path}: ${errorMessage}`,
         );
       }
       throw error;
@@ -234,52 +267,7 @@ export class PrettierFormatter extends BaseFormatter {
     });
   }
 
-  /**
-   * Override check() to compute diffs on-the-fly by running prettier
-   */
   async check(): Promise<ICheckResult> {
-    const changes = await this.analyze();
-    const diffs: ICheckResult['diffs'] = [];
-
-    for (const change of changes) {
-      if (change.type !== 'modify') continue;
-
-      try {
-        // Read current content
-        const currentContent = (await plugins.smartfs
-          .file(change.path)
-          .encoding('utf8')
-          .read()) as string;
-
-        // Skip files without extension (prettier can't infer parser)
-        const fileExt = plugins.path.extname(change.path).toLowerCase();
-        if (!fileExt) continue;
-
-        // Format with prettier to get what it would produce
-        const prettier = await import('prettier');
-        const formatted = await prettier.format(currentContent, {
-          filepath: change.path,
-          ...(await this.getPrettierConfig()),
-        });
-
-        // Only add to diffs if content differs
-        if (formatted !== currentContent) {
-          diffs.push({
-            path: change.path,
-            type: 'modify',
-            before: currentContent,
-            after: formatted,
-          });
-        }
-      } catch (error) {
-        // Skip files that can't be processed
-        logVerbose(`Skipping diff for ${change.path}: ${error.message}`);
-      }
-    }
-
-    return {
-      hasDiff: diffs.length > 0,
-      diffs,
-    };
+    return await super.check();
   }
 }
diff --git a/ts/mod_format/index.ts b/ts/mod_format/index.ts
index 5ba48e5..59bdfe2 100644
--- a/ts/mod_format/index.ts
+++ b/ts/mod_format/index.ts
@@ -22,6 +22,7 @@ import { TsconfigFormatter } from "./formatters/tsconfig.formatter.js";
 import { PrettierFormatter } from "./formatters/prettier.formatter.js";
 import { ReadmeFormatter } from "./formatters/readme.formatter.js";
 import { CopyFormatter } from "./formatters/copy.formatter.js";
+import type { ICheckResult, IFormatPlan } from "./interfaces.format.js";
 
 /**
  * Rename npmextra.json or smartconfig.json to .smartconfig.json
@@ -94,9 +95,39 @@ const getFormatConfig = async () => {
   };
 };
 
+const normalizeModuleList = (value: unknown): string[] => {
+  if (Array.isArray(value)) {
+    return value.flatMap((item) => normalizeModuleList(item));
+  }
+  if (typeof value !== "string") {
+    return [];
+  }
+  return value
+    .split(",")
+    .map((item) => item.trim())
+    .filter(Boolean);
+};
+
+const getPlanStatus = (plan: IFormatPlan) => {
+  const errorWarnings = plan.warnings.filter(
+    (warning) => warning.level === "error",
+  );
+  const hasChanges = plan.summary.totalFiles > 0;
+  const hasErrors = errorWarnings.length > 0;
+
+  return {
+    ok: !hasChanges && !hasErrors,
+    hasChanges,
+    hasErrors,
+    errorCount: errorWarnings.length,
+  };
+};
+
 const createActiveFormatters = async (options: {
   interactive: boolean;
   jsonOutput: boolean;
+  only?: string[];
+  skip?: string[];
 }) => {
   const project = await Project.fromCwd({ requireProjectType: false });
   const context = new FormatContext(options);
@@ -107,11 +138,19 @@ const createActiveFormatters = async (options: {
     ([, FormatterClass]) => new FormatterClass(context, project),
   );
 
+  const onlyModules = options.only?.length
+    ? options.only
+    : formatConfig.modules.only;
+  const skipModules = [
+    ...formatConfig.modules.skip,
+    ...(options.skip || []),
+  ];
+
   const activeFormatters = formatters.filter((formatter) => {
-    if (formatConfig.modules.only.length > 0) {
-      return formatConfig.modules.only.includes(formatter.name);
+    if (onlyModules.length > 0) {
+      return onlyModules.includes(formatter.name);
     }
-    if (formatConfig.modules.skip.includes(formatter.name)) {
+    if (skipModules.includes(formatter.name)) {
       return false;
     }
     return true;
@@ -129,11 +168,15 @@ const buildFormatPlan = async (options: {
   fromPlan?: string;
   interactive: boolean;
   jsonOutput: boolean;
+  only?: string[];
+  skip?: string[];
 }) => {
   const { context, planner, formatConfig, activeFormatters } =
     await createActiveFormatters({
       interactive: options.interactive,
       jsonOutput: options.jsonOutput,
+      only: options.only,
+      skip: options.skip,
     });
 
   const plan = options.fromPlan
@@ -167,6 +210,182 @@ const serializePlan = (plan: any) => {
   };
 };
 
+const buildFormatFixPrompt = (
+  plan: IFormatPlan,
+  extraInstructions: string,
+): string => {
+  const promptParts = [
+    "Other /c-* commands can be found at ~/.config/opencode/commands/*",
+    "# gitzone format fix",
+    "",
+    `Working directory: ${process.cwd()}`,
+    "",
+    "Repair project formatting so `gitzone format check --json` passes.",
+    "",
+    "Rules:",
+    "- Read `.smartconfig.json`, `package.json`, `tsconfig.json`, and the current format plan before editing.",
+    "- Prefer deterministic gitzone standards, bundled assets, and existing project conventions.",
+    "- Keep changes focused on formatting, metadata normalization, templates, and config consistency.",
+    "- Do not commit, release, install dependencies, or modify unrelated files.",
+    "- Use pnpm commands only if commands are needed.",
+    "- Run `gitzone format --write --yes` after changes.",
+    "- Run `gitzone format check --json` after changes and keep fixing until it passes.",
+    "- Run `git diff --check` after changes to catch whitespace problems.",
+    "",
+    "Current format plan:",
+    JSON.stringify(serializePlan(plan), null, 2),
+  ];
+
+  if (extraInstructions) {
+    promptParts.push("", "Additional user instructions:", extraInstructions);
+  }
+
+  return promptParts.join("\n");
+};
+
+const handleFormatFix = async (
+  options: Record<string, any>,
+  mode: ICliMode,
+): Promise<void> => {
+  if (mode.json) {
+    printJson({
+      ok: false,
+      error:
+        "JSON output is not supported for `gitzone format fix`. Use `gitzone format check --json` for machine-readable diagnostics.",
+    });
+    process.exitCode = 1;
+    return;
+  }
+
+  const extraInstructions = (options._?.slice(2).join(" ") || "").trim();
+  const force = Boolean(options.force);
+  const autoApprove = Boolean(options.yes || mode.yes);
+  const formatConfig = await getFormatConfig();
+  const interactive =
+    options.interactive ?? (mode.interactive && formatConfig.interactive);
+  const only = normalizeModuleList(options.only);
+  const skip = normalizeModuleList(options.skip);
+
+  const buildCurrentPlan = async () => {
+    return await buildFormatPlan({
+      interactive,
+      jsonOutput: false,
+      only,
+      skip,
+    });
+  };
+
+  logger.log("info", "Analyzing project for format fixes...");
+  let { plan } = await buildCurrentPlan();
+  let status = getPlanStatus(plan);
+
+  if (status.ok && !extraInstructions && !force) {
+    logger.log(
+      "success",
+      "Format check found no issues. Use `gitzone format fix --force` to run opencode anyway.",
+    );
+    return;
+  }
+
+  if (!autoApprove) {
+    if (!mode.interactive) {
+      throw new Error(
+        "Format fix requires an interactive terminal or `-y` to run non-interactively.",
+      );
+    }
+    const confirmed = await plugins.smartinteract.SmartInteract.getCliConfirmation(
+      `Run format fixes? (${plan.summary.totalFiles} planned change(s), ${status.errorCount} error warning(s))`,
+      true,
+    );
+    if (!confirmed) {
+      logger.log("info", "Format fix cancelled.");
+      return;
+    }
+  }
+
+  if (status.hasChanges) {
+    logger.log("info", "Applying deterministic format changes first...");
+    await run({
+      _: ["format"],
+      write: true,
+      yes: true,
+      interactive: false,
+      verbose: options.verbose,
+      detailed: options.detailed,
+      only: options.only,
+      skip: options.skip,
+    });
+
+    ({ plan } = await buildCurrentPlan());
+    status = getPlanStatus(plan);
+    if (status.ok && !extraInstructions && !force) {
+      logger.log("success", "Format fix completed successfully.");
+      return;
+    }
+  }
+
+  const opencodeArgs = [
+    "run",
+    "--title",
+    "gitzone format fix",
+    "--dir",
+    process.cwd(),
+  ];
+  if (autoApprove) {
+    opencodeArgs.push("--dangerously-skip-permissions");
+  }
+  opencodeArgs.push(buildFormatFixPrompt(plan, extraInstructions));
+
+  logger.log("info", "Starting opencode format fix...");
+  const smartshellInstance = new plugins.smartshell.Smartshell({
+    executor: "bash",
+    sourceFilePaths: [],
+  });
+
+  let result: plugins.smartshell.IExecResult;
+  try {
+    result = await smartshellInstance.execSpawn("opencode", opencodeArgs, {
+      stdio: "inherit",
+    });
+  } catch (error) {
+    throw new Error(
+      `Failed to run opencode: ${error instanceof Error ? error.message : String(error)}`,
+    );
+  }
+
+  if (result.exitCode !== 0) {
+    logger.log("error", `opencode exited with code ${result.exitCode}`);
+    process.exitCode = result.exitCode || 1;
+    return;
+  }
+
+  logger.log("info", "Running deterministic format pass after opencode...");
+  await run({
+    _: ["format"],
+    write: true,
+    yes: true,
+    interactive: false,
+    verbose: options.verbose,
+    detailed: options.detailed,
+    only: options.only,
+    skip: options.skip,
+  });
+
+  const { planner: finalPlanner, plan: finalPlan } = await buildCurrentPlan();
+  await finalPlanner.displayPlan(finalPlan, options.detailed);
+  const finalStatus = getPlanStatus(finalPlan);
+  if (finalStatus.ok) {
+    logger.log("success", "Format fix completed successfully.");
+    return;
+  }
+
+  logger.log(
+    "error",
+    `Format fix left ${finalPlan.summary.totalFiles} planned change(s) and ${finalStatus.errorCount} error warning(s).`,
+  );
+  process.exitCode = 1;
+};
+
 export let run = async (
   options: {
     write?: boolean;
@@ -194,8 +413,25 @@ export let run = async (
     setVerboseMode(true);
   }
 
+  if (subcommand === "fix") {
+    await handleFormatFix(options, mode);
+    return;
+  }
+
   const shouldWrite = options.write ?? options.dryRun === false;
   const treatAsPlan = subcommand === "plan";
+  const treatAsCheck = subcommand === "check" || Boolean(options.check);
+
+  if (treatAsCheck && shouldWrite) {
+    const error = "`gitzone format check` is read-only and cannot be combined with --write.";
+    if (mode.json) {
+      printJson({ ok: false, error });
+    } else {
+      logger.log("error", error);
+    }
+    process.exitCode = 1;
+    return;
+  }
 
   if (mode.json && shouldWrite) {
     printJson({
@@ -212,7 +448,9 @@ export let run = async (
   const formatConfig = await getFormatConfig();
   const interactive =
     options.interactive ?? (mode.interactive && formatConfig.interactive);
-  const autoApprove = options.yes ?? formatConfig.autoApprove;
+  const autoApprove = options.yes ?? (mode.yes || formatConfig.autoApprove);
+  const only = normalizeModuleList(options.only);
+  const skip = normalizeModuleList(options.skip);
 
   try {
     const planBuilder = async () => {
@@ -220,6 +458,8 @@ export let run = async (
         fromPlan: options.fromPlan,
         interactive,
         jsonOutput: mode.json,
+        only,
+        skip,
       });
     };
 
@@ -231,7 +471,16 @@ export let run = async (
       : await planBuilder();
 
     if (mode.json) {
-      printJson(serializePlan(plan));
+      const serializedPlan = serializePlan(plan);
+      if (treatAsCheck) {
+        const status = getPlanStatus(plan);
+        printJson({ ok: status.ok, ...serializedPlan });
+        if (!status.ok) {
+          process.exitCode = 1;
+        }
+        return;
+      }
+      printJson(serializedPlan);
       return;
     }
 
@@ -251,6 +500,20 @@ export let run = async (
       return;
     }
 
+    if (treatAsCheck) {
+      const status = getPlanStatus(plan);
+      if (status.ok) {
+        logger.log("success", "Format check passed");
+      } else {
+        logger.log(
+          "error",
+          `Format check failed: ${plan.summary.totalFiles} planned change(s), ${status.errorCount} error warning(s)`,
+        );
+        process.exitCode = 1;
+      }
+      return;
+    }
+
     // Show diffs if explicitly requested or before interactive write confirmation
     const showDiffs =
       options.diff || (shouldWrite && interactive && !autoApprove);
@@ -314,7 +577,6 @@ export let run = async (
   }
 };
 
-import type { ICheckResult } from "./interfaces.format.js";
 export type { ICheckResult };
 
 /**
@@ -363,7 +625,7 @@ export function showHelp(mode?: ICliMode): void {
   if (mode?.json) {
     printJson({
       command: "format",
-      usage: "gitzone format [plan] [options]",
+      usage: "gitzone format [plan|check|fix] [options]",
       description:
         "Plans formatting changes by default and applies them only with --write.",
       flags: [
@@ -393,19 +655,33 @@ export function showHelp(mode?: ICliMode): void {
           flag: "--diff",
           description: "Show per-file diffs before applying changes",
         },
+        {
+          flag: "--only <modules>",
+          description: "Run only the comma-separated formatter modules",
+        },
+        {
+          flag: "--skip <modules>",
+          description: "Skip the comma-separated formatter modules",
+        },
+        {
+          flag: "--force",
+          description: "Run `format fix` even when the deterministic plan is clean",
+        },
         { flag: "--json", description: "Emit a read-only format plan as JSON" },
       ],
       examples: [
         "gitzone format",
         "gitzone format plan --json",
+        "gitzone format check",
         "gitzone format --write --yes",
+        "gitzone format fix",
       ],
     });
     return;
   }
 
   console.log("");
-  console.log("Usage: gitzone format [plan] [options]");
+  console.log("Usage: gitzone format [plan|check|fix] [options]");
   console.log("");
   console.log(
     "Plans formatting changes by default and applies them only with --write.",
@@ -424,11 +700,16 @@ export function showHelp(mode?: ICliMode): void {
   console.log(
     "  --diff               Show per-file diffs before applying changes",
   );
+  console.log("  --only <modules>     Run only comma-separated formatter modules");
+  console.log("  --skip <modules>     Skip comma-separated formatter modules");
+  console.log("  --force              Run format fix even when the plan is clean");
   console.log("  --json               Emit a read-only format plan as JSON");
   console.log("");
   console.log("Examples:");
   console.log("  gitzone format");
   console.log("  gitzone format plan --json");
+  console.log("  gitzone format check");
   console.log("  gitzone format --write --yes");
+  console.log("  gitzone format fix");
   console.log("");
 }
diff --git a/ts/mod_format/interfaces.format.ts b/ts/mod_format/interfaces.format.ts
index 9e30691..c0a53ed 100644
--- a/ts/mod_format/interfaces.format.ts
+++ b/ts/mod_format/interfaces.format.ts
@@ -1,3 +1,9 @@
+export type IFormatWarning = {
+  level: 'info' | 'warning' | 'error';
+  message: string;
+  module: string;
+};
+
 export type IFormatPlan = {
   summary: {
     totalFiles: number;
@@ -5,17 +11,8 @@ export type IFormatPlan = {
     filesModified: number;
     filesRemoved: number;
   };
-  changes: Array<{
-    type: 'create' | 'modify' | 'delete';
-    path: string;
-    module: string;
-    description: string;
-  }>;
-  warnings: Array<{
-    level: 'info' | 'warning' | 'error';
-    message: string;
-    module: string;
-  }>;
+  changes: IPlannedChange[];
+  warnings: IFormatWarning[];
 };
 
 export type IPlannedChange = {
diff --git a/ts/mod_standard/index.ts b/ts/mod_standard/index.ts
index df20e21..f9e5c36 100644
--- a/ts/mod_standard/index.ts
+++ b/ts/mod_standard/index.ts
@@ -202,6 +202,7 @@ export async function showHelp(
   console.log("  gitzone commit recommend --json");
   console.log("  gitzone release --plan");
   console.log("  gitzone format plan --json");
+  console.log("  gitzone format check");
   console.log("  gitzone services set mongodb,minio");
   console.log("  gitzone tools update");
   console.log("");