diff --git a/packages/dev/package.json b/packages/dev/package.json
index 14d4b01..f75131c 100644
--- a/packages/dev/package.json
+++ b/packages/dev/package.json
@@ -28,6 +28,7 @@
     "pezkuwi-dev-copy-dir": "./scripts/pezkuwi-dev-copy-dir.mjs",
     "pezkuwi-dev-copy-to": "./scripts/pezkuwi-dev-copy-to.mjs",
     "pezkuwi-dev-deno-map": "./scripts/pezkuwi-dev-deno-map.mjs",
+    "pezkuwi-dev-migrate-eslint10": "./scripts/pezkuwi-dev-migrate-eslint10.mjs",
     "pezkuwi-dev-run-lint": "./scripts/pezkuwi-dev-run-lint.mjs",
     "pezkuwi-dev-run-node-ts": "./scripts/pezkuwi-dev-run-node-ts.mjs",
     "pezkuwi-dev-run-test": "./scripts/pezkuwi-dev-run-test.mjs",
diff --git a/packages/dev/scripts/pezkuwi-dev-deno-map.mjs b/packages/dev/scripts/pezkuwi-dev-deno-map.mjs
index 544d012..ba15d13 100755
--- a/packages/dev/scripts/pezkuwi-dev-deno-map.mjs
+++ b/packages/dev/scripts/pezkuwi-dev-deno-map.mjs
@@ -19,7 +19,7 @@ const [e, i] = fs
 
 if (!fs.existsSync('mod.ts')) {
   fs.writeFileSync('mod.ts', `// Copyright 2017-${new Date().getFullYear()} @pezkuwi/dev authors & contributors\n// SPDX-License-Identifier: Apache-2.0\n\n// auto-generated via pezkuwi-dev-deno-map, do not edit\n\n// This is a Deno file, so we can allow .ts imports
-  /* eslint-disable import/extensions */\n\n${e.join('\n')}\n`);
+  /* eslint-disable import-x/extensions */\n\n${e.join('\n')}\n`);
 }
 
 if (fs.existsSync('import_map.in.json')) {
diff --git a/packages/dev/scripts/pezkuwi-dev-migrate-eslint10.mjs b/packages/dev/scripts/pezkuwi-dev-migrate-eslint10.mjs
new file mode 100755
index 0000000..2fd6a77
--- /dev/null
+++ b/packages/dev/scripts/pezkuwi-dev-migrate-eslint10.mjs
@@ -0,0 +1,134 @@
+#!/usr/bin/env node
+// Copyright 2017-2026 @pezkuwi/dev authors & contributors
+// SPDX-License-Identifier: Apache-2.0
+
+// Renames rules in eslint-disable / eslint-enable comments for the 0.86
+// toolchain (eslint 10, typescript-eslint 8, @stylistic, import-x).
+//
+// A disable comment that names a rule which no longer exists under that name
+// disables nothing: eslint reports it as unused and `--fix` deletes it, after
+// which the rule it was meant to silence applies. Run this before the first
+// lint on 0.86, in the repository root:
+//
+//   pezkuwi-dev-migrate-eslint10           # rewrite tracked files
+//   pezkuwi-dev-migrate-eslint10 --check   # report, change nothing (exit 1 if anything would change)
+//
+// It also rewrites such comments inside string literals, which is how code
+// generators emit them.
+
+import stylisticPlugin from '@stylistic/eslint-plugin';
+import { builtinRules } from 'eslint/use-at-your-own-risk';
+import importPlugin from 'eslint-plugin-import-x';
+import { execFileSync } from 'node:child_process';
+import fs from 'node:fs';
+
+const STYLISTIC = new Set(Object.keys(stylisticPlugin.rules));
+const IMPORT_X = new Set(Object.keys(importPlugin.rules));
+
+/** @type {Map<string, string[]>} */
+const RENAME = new Map();
+
+// Core rules eslint 10 deprecated, with the successor it names itself. The
+// rule metadata (meta.deprecated.replacedBy) is only exposed here, so this
+// reads it rather than keeping a hand-written copy that could drift.
+// eslint-disable-next-line @typescript-eslint/no-deprecated
+for (const [name, rule] of builtinRules) {
+  const replacedBy = rule.meta?.deprecated && typeof rule.meta.deprecated === 'object'
+    ? rule.meta.deprecated.replacedBy
+    : undefined;
+
+  if (replacedBy?.length === 1) {
+    const [{ plugin, rule: next }] = replacedBy;
+
+    if (next?.name) {
+      RENAME.set(name, [plugin?.name === '@stylistic/eslint-plugin' ? `@stylistic/${next.name}` : next.name]);
+    }
+  }
+}
+
+// typescript-eslint 8 removed its formatting rules; they live in @stylistic.
+for (const name of ['block-spacing', 'brace-style', 'comma-dangle', 'comma-spacing', 'func-call-spacing', 'indent', 'key-spacing', 'keyword-spacing', 'lines-around-comment', 'lines-between-class-members', 'member-delimiter-style', 'no-extra-parens', 'no-extra-semi', 'object-curly-spacing', 'padding-line-between-statements', 'quotes', 'semi', 'space-before-blocks', 'space-before-function-paren', 'space-infix-ops', 'type-annotation-spacing']) {
+  const next = name === 'func-call-spacing' ? 'function-call-spacing' : name;
+
+  if (STYLISTIC.has(next)) {
+    RENAME.set(`@typescript-eslint/${name}`, [`@stylistic/${next}`]);
+  }
+}
+
+// Other typescript-eslint 8 removals and renames.
+RENAME.set('@typescript-eslint/ban-types', ['@typescript-eslint/no-empty-object-type', '@typescript-eslint/no-unsafe-function-type', '@typescript-eslint/no-wrapper-object-types']);
+RENAME.set('@typescript-eslint/no-empty-interface', ['@typescript-eslint/no-empty-object-type']);
+RENAME.set('@typescript-eslint/no-loss-of-precision', ['no-loss-of-precision']);
+RENAME.set('@typescript-eslint/no-throw-literal', ['@typescript-eslint/only-throw-error']);
+RENAME.set('@typescript-eslint/no-var-requires', ['@typescript-eslint/no-require-imports']);
+RENAME.set('deprecation/deprecation', ['@typescript-eslint/no-deprecated']);
+
+// The react formatting rules config/eslint.rules.js (overrideJsx) now takes
+// from @stylistic; keep this list in step with it. (The config is not
+// imported here: loading it reads the repository's tsconfig.base.json.)
+for (const name of ['jsx-closing-bracket-location', 'jsx-first-prop-new-line', 'jsx-max-props-per-line', 'jsx-newline', 'jsx-props-no-multi-spaces', 'jsx-sort-props', 'jsx-tag-spacing']) {
+  if (STYLISTIC.has(name)) {
+    RENAME.set(`react/${name}`, [`@stylistic/${name}`]);
+  }
+}
+
+/**
+ * @param {string} name
+ * @returns {string[]}
+ */
+function rename (name) {
+  if (RENAME.has(name)) {
+    return /** @type {string[]} */ (RENAME.get(name));
+  } else if (name.startsWith('import/') && IMPORT_X.has(name.slice(7))) {
+    return [`import-x/${name.slice(7)}`];
+  }
+
+  return [name];
+}
+
+// eslint-disable, eslint-disable-line, eslint-disable-next-line, eslint-enable
+// followed by a rule list, optionally ending in `-- description`.
+const DIRECTIVE = /(eslint-(?:disable(?:-next-line|-line)?|enable))([ \t]+)([^\n*'"`]*?)([ \t]*(?:--[^\n*]*)?)(?=\*\/|\n|$|['"`])/g;
+
+const files = execFileSync('git', ['ls-files', '-z', '--', '*.ts', '*.tsx', '*.js', '*.jsx', '*.mjs', '*.cjs', '*.cts', '*.mts'], { encoding: 'utf-8' })
+  .split('\0')
+  .filter((f) => f && !/(^|\/)(node_modules|build|build-[^/]+)\//.test(f));
+const check = process.argv.includes('--check');
+let changedFiles = 0;
+let changedComments = 0;
+
+for (const file of files) {
+  const src = fs.readFileSync(file, 'utf-8');
+  const out = src.replace(DIRECTIVE, (/** @type {string} */ all, /** @type {string} */ kind, /** @type {string} */ gap, /** @type {string} */ list, /** @type {string} */ tail) => {
+    if (!list.trim()) {
+      return all;
+    }
+
+    const names = list.split(',').map((n) => n.trim()).filter(Boolean);
+    const next = [...new Set(names.flatMap(rename))];
+
+    if (next.join(',') === names.join(',')) {
+      return all;
+    }
+
+    changedComments++;
+
+    return `${kind}${gap}${next.join(', ')}${tail}`;
+  });
+
+  if (out !== src) {
+    changedFiles++;
+
+    if (check) {
+      console.log(`would change: ${file}`);
+    } else {
+      fs.writeFileSync(file, out);
+    }
+  }
+}
+
+console.log(`${check ? 'would rewrite' : 'rewrote'} ${changedComments} directive(s) in ${changedFiles} file(s)`);
+
+if (check && changedFiles) {
+  process.exit(1);
+}
diff --git a/packages/dev/src/migrateEslint10.spec.ts b/packages/dev/src/migrateEslint10.spec.ts
new file mode 100644
index 0000000..e412400
--- /dev/null
+++ b/packages/dev/src/migrateEslint10.spec.ts
@@ -0,0 +1,87 @@
+// Copyright 2017-2026 @pezkuwi/dev authors & contributors
+// SPDX-License-Identifier: Apache-2.0
+
+/// <reference types="@pezkuwi/dev-test/globals.d.ts" />
+
+import { execFileSync } from 'node:child_process';
+import fs from 'node:fs';
+import os from 'node:os';
+import path from 'node:path';
+
+const SCRIPT = path.join(process.cwd(), 'packages/dev/scripts/pezkuwi-dev-migrate-eslint10.mjs');
+
+// Spelt so that the tool, run on this repository, does not rewrite its own
+// fixture: the source never contains the directive it is testing.
+const D = 'eslint-' + 'disable';
+
+const BEFORE = `/* ${D} quotes */
+/* ${D} quote-props */
+// ${D}-next-line deprecation/deprecation
+// ${D}-next-line import/export -- types and values share the name
+// ${D}-next-line @typescript-eslint/no-empty-interface,no-use-before-define
+// ${D}-next-line indent, @typescript-eslint/indent
+// ${D}-next-line react/jsx-max-props-per-line
+const header = '/* ${D} quotes */';
+/* ${D} */
+// ${D}-next-line @typescript-eslint/no-explicit-any
+`;
+
+const AFTER = `/* eslint-disable @stylistic/quotes */
+/* eslint-disable @stylistic/quote-props */
+// eslint-disable-next-line @typescript-eslint/no-deprecated
+// eslint-disable-next-line import-x/export -- types and values share the name
+// eslint-disable-next-line @typescript-eslint/no-empty-object-type, no-use-before-define
+// eslint-disable-next-line @stylistic/indent
+// eslint-disable-next-line @stylistic/jsx-max-props-per-line
+const header = '/* eslint-disable @stylistic/quotes */';
+/* eslint-disable */
+// eslint-disable-next-line @typescript-eslint/no-explicit-any
+`;
+
+function inRepo (content: string, args: string[] = []): { out: string; code: number; file: string } {
+  const dir = fs.mkdtempSync(path.join(os.tmpdir(), 'migrate-eslint10-'));
+  const file = path.join(dir, 'sample.ts');
+
+  try {
+    fs.writeFileSync(file, content);
+    execFileSync('git', ['init', '-q'], { cwd: dir });
+    execFileSync('git', ['add', 'sample.ts'], { cwd: dir });
+
+    let code = 0;
+    let out = '';
+
+    try {
+      out = execFileSync(process.execPath, [SCRIPT, ...args], { cwd: dir, encoding: 'utf-8' });
+    } catch (error) {
+      code = (error as { status: number }).status;
+      out = (error as { stdout: string }).stdout;
+    }
+
+    return { code, file: fs.readFileSync(file, 'utf-8'), out };
+  } finally {
+    fs.rmSync(dir, { force: true, recursive: true });
+  }
+}
+
+describe('pezkuwi-dev-migrate-eslint10', (): void => {
+  it('renames rules in disable comments, and in strings that emit them', (): void => {
+    const { file, out } = inRepo(BEFORE);
+
+    expect(file).toEqual(AFTER);
+    expect(out.includes('rewrote 8 directive(s) in 1 file(s)')).toEqual(true);
+  });
+
+  it('leaves current rule names and bare disables alone', (): void => {
+    const { file, out } = inRepo(AFTER);
+
+    expect(file).toEqual(AFTER);
+    expect(out.includes('rewrote 0 directive(s) in 0 file(s)')).toEqual(true);
+  });
+
+  it('--check reports and changes nothing, exiting 1 when there is work', (): void => {
+    const { code, file } = inRepo(BEFORE, ['--check']);
+
+    expect(file).toEqual(BEFORE);
+    expect(code).toEqual(1);
+  });
+});