diff --git a/.changeset/unify-pathe-path-normalization.md b/.changeset/unify-pathe-path-normalization.md
new file mode 100644
index 00000000..ffecd6e8
--- /dev/null
+++ b/.changeset/unify-pathe-path-normalization.md
@@ -0,0 +1,6 @@
+---
+"@moonshot-ai/agent-core": patch
+"@moonshot-ai/kaos": patch
+---
+
+Unify path normalization by replacing ad-hoc `toForwardSlashes` helpers with `pathe`. Remove unnecessary `node:path/win32` branching in path-access policies and tools, and inline unused `joinPath` wrappers. Platform-specific path separators are now handled consistently through a single module.
diff --git a/packages/agent-core/package.json b/packages/agent-core/package.json
index 0cd886f3..9ef2e428 100644
--- a/packages/agent-core/package.json
+++ b/packages/agent-core/package.json
@@ -65,6 +65,7 @@
     "linkedom": "^0.18.12",
     "nunjucks": "^3.2.4",
     "open": "^10.2.0",
+    "pathe": "^2.0.3",
     "picomatch": "^4.0.4",
     "proper-lockfile": "^4.1.2",
     "regexp.escape": "^2.0.1",
diff --git a/packages/agent-core/src/agent/index.ts b/packages/agent-core/src/agent/index.ts
index 67feb6e7..222f5c40 100644
--- a/packages/agent-core/src/agent/index.ts
+++ b/packages/agent-core/src/agent/index.ts
@@ -1,5 +1,5 @@
 import { createHash } from 'node:crypto';
-import { join } from 'node:path';
+import { join } from 'pathe';
 
 import { ErrorCodes, KimiError, makeErrorPayload } from '#/errors';
 import { log } from '#/logging/logger';
diff --git a/packages/agent-core/src/agent/permission/path-glob-match.ts b/packages/agent-core/src/agent/permission/path-glob-match.ts
index 5cecc179..9e2fd5cf 100644
--- a/packages/agent-core/src/agent/permission/path-glob-match.ts
+++ b/packages/agent-core/src/agent/permission/path-glob-match.ts
@@ -1,5 +1,4 @@
-import * as posixPath from 'node:path/posix';
-import * as win32Path from 'node:path/win32';
+import { isAbsolute, join, parse } from 'pathe';
 
 import picomatch from 'picomatch';
 
@@ -14,7 +13,6 @@ export interface PermissionPathMatchOptions {
 
 interface PathMatchSemantics {
   readonly pathClass: PathClass;
-  readonly path: typeof posixPath;
 }
 
 /**
@@ -90,8 +88,8 @@ function canonicalizePathPattern(
   semantics: PathMatchSemantics,
   pathOptions: PermissionPathMatchOptions | undefined,
 ): string | undefined {
-  const expanded = expandUserPath(value, semantics, pathOptions?.homeDir);
-  const cwd = pathOptions?.cwd ?? defaultCwdForPath(expanded, semantics);
+  const expanded = expandUserPath(value, semantics.pathClass, pathOptions?.homeDir);
+  const cwd = pathOptions?.cwd ?? defaultCwdForPath(expanded);
   if (cwd === undefined) return undefined;
   try {
     return canonicalizePath(expanded, cwd, semantics.pathClass);
@@ -102,20 +100,20 @@ function canonicalizePathPattern(
 
 function expandUserPath(
   value: string,
-  semantics: PathMatchSemantics,
+  pathClass: PathClass,
   homeDir: string | undefined,
 ): string {
   if (homeDir === undefined) return value;
   if (value === '~') return homeDir;
-  if (value.startsWith('~/') || (semantics.pathClass === 'win32' && value.startsWith('~\\'))) {
-    return semantics.path.join(homeDir, value.slice(2));
+  if (value.startsWith('~/') || (pathClass === 'win32' && value.startsWith('~\\'))) {
+    return join(homeDir, value.slice(2));
   }
   return value;
 }
 
-function defaultCwdForPath(value: string, semantics: PathMatchSemantics): string | undefined {
-  if (!semantics.path.isAbsolute(value)) return undefined;
-  return semantics.path.parse(value).root;
+function defaultCwdForPath(value: string): string | undefined {
+  if (!isAbsolute(value)) return undefined;
+  return parse(value).root;
 }
 
 function pathMatchSemantics(
@@ -136,10 +134,7 @@ function pathMatchSemantics(
     })
       ? 'win32'
       : 'posix');
-  return {
-    pathClass,
-    path: pathClass === 'win32' ? win32Path : posixPath,
-  };
+  return { pathClass };
 }
 
 function addPathVariant(variants: Set<string>, value: string, pathClass: PathClass): void {
diff --git a/packages/agent-core/src/agent/permission/policies/default-git-cwd-write.ts b/packages/agent-core/src/agent/permission/policies/default-git-cwd-write.ts
index b5bc7bac..c5b05b31 100644
--- a/packages/agent-core/src/agent/permission/policies/default-git-cwd-write.ts
+++ b/packages/agent-core/src/agent/permission/policies/default-git-cwd-write.ts
@@ -1,4 +1,4 @@
-import * as posixPath from 'node:path/posix';
+import { join, relative, sep } from 'pathe';
 
 import type { Kaos } from '@moonshot-ai/kaos';
 
@@ -89,20 +89,20 @@ function readStringField(args: unknown, key: string): string | undefined {
 function isGitControlPath(targetPath: string, cwd: string, marker: GitWorkTreeMarker): boolean {
   const foldedTarget = targetPath.toLowerCase();
   return (
-    posixPath.relative(cwd.toLowerCase(), foldedTarget).split(posixPath.sep).includes('.git') ||
+    relative(cwd.toLowerCase(), foldedTarget).split(sep).includes('.git') ||
     isWithinDirectory(foldedTarget, marker.dotGitPath.toLowerCase(), 'posix') ||
     isWithinDirectory(foldedTarget, marker.controlDirPath.toLowerCase(), 'posix')
   );
 }
 
 async function hasSymlinkInPath(kaos: Kaos, cwd: string, targetPath: string): Promise<boolean> {
-  const relative = posixPath.relative(cwd, targetPath);
+  const relPath = relative(cwd, targetPath);
   const parts = [cwd];
 
   let current = cwd;
-  for (const part of relative.split(posixPath.sep)) {
+  for (const part of relPath.split(sep)) {
     if (part.length === 0 || part === '.') continue;
-    current = posixPath.join(current, part);
+    current = join(current, part);
     parts.push(current);
   }
 
diff --git a/packages/agent-core/src/agent/plan/index.ts b/packages/agent-core/src/agent/plan/index.ts
index e2508e8a..2078e54f 100644
--- a/packages/agent-core/src/agent/plan/index.ts
+++ b/packages/agent-core/src/agent/plan/index.ts
@@ -1,5 +1,5 @@
 import { randomUUID } from 'node:crypto';
-import { dirname, join } from 'node:path';
+import { dirname, join } from 'pathe';
 
 import type { Agent } from '..';
 import { generateHeroSlug } from '../../utils/hero-slug';
diff --git a/packages/agent-core/src/agent/records/persistence.ts b/packages/agent-core/src/agent/records/persistence.ts
index 3b7ff66c..f2fc4a93 100644
--- a/packages/agent-core/src/agent/records/persistence.ts
+++ b/packages/agent-core/src/agent/records/persistence.ts
@@ -1,6 +1,6 @@
 import { createReadStream } from 'node:fs';
 import { mkdir, open } from 'node:fs/promises';
-import { dirname } from 'node:path';
+import { dirname } from 'pathe';
 
 import { syncDir } from '../../utils/fs';
 import { type AgentRecord, type AgentRecordPersistence } from './types';
diff --git a/packages/agent-core/src/config/path.ts b/packages/agent-core/src/config/path.ts
index d8d80f45..3921e8ba 100644
--- a/packages/agent-core/src/config/path.ts
+++ b/packages/agent-core/src/config/path.ts
@@ -1,6 +1,6 @@
 import { mkdirSync } from 'node:fs';
 import { homedir } from 'node:os';
-import { join } from 'node:path';
+import { join } from 'pathe';
 
 export function resolveKimiHome(homeDir?: string | undefined): string {
   return homeDir ?? process.env['KIMI_CODE_HOME'] ?? join(homedir(), '.kimi-code');
diff --git a/packages/agent-core/src/config/toml.ts b/packages/agent-core/src/config/toml.ts
index a049c1de..61284de1 100644
--- a/packages/agent-core/src/config/toml.ts
+++ b/packages/agent-core/src/config/toml.ts
@@ -1,6 +1,6 @@
 import { existsSync, readFileSync } from 'node:fs';
 import { mkdir, open } from 'node:fs/promises';
-import { dirname } from 'node:path';
+import { dirname } from 'pathe';
 
 import { ErrorCodes, KimiError } from '#/errors';
 import {
diff --git a/packages/agent-core/src/logging/logger.ts b/packages/agent-core/src/logging/logger.ts
index 7112de2c..fe4ce278 100644
--- a/packages/agent-core/src/logging/logger.ts
+++ b/packages/agent-core/src/logging/logger.ts
@@ -1,4 +1,4 @@
-import { join } from 'node:path';
+import { join } from 'pathe';
 
 import { extractError, formatEntry, redactCtx } from './formatter';
 import { RotatingFileSink } from './sinks';
diff --git a/packages/agent-core/src/logging/sinks.ts b/packages/agent-core/src/logging/sinks.ts
index ed7c0701..e7ceb23b 100644
--- a/packages/agent-core/src/logging/sinks.ts
+++ b/packages/agent-core/src/logging/sinks.ts
@@ -1,6 +1,6 @@
 import { mkdir, open, rename, stat, unlink } from 'node:fs/promises';
 import { appendFileSync, mkdirSync } from 'node:fs';
-import { dirname } from 'node:path';
+import { dirname } from 'pathe';
 
 import { syncDir } from '#/utils/fs';
 
diff --git a/packages/agent-core/src/mcp/config-loader.ts b/packages/agent-core/src/mcp/config-loader.ts
index 0c29abff..04ad7230 100644
--- a/packages/agent-core/src/mcp/config-loader.ts
+++ b/packages/agent-core/src/mcp/config-loader.ts
@@ -1,5 +1,5 @@
 import { readFile } from 'node:fs/promises';
-import { join } from 'node:path';
+import { join } from 'pathe';
 
 import { resolveKimiHome } from '#/config/path';
 import { McpServerConfigSchema, type McpServerConfig } from '#/config/schema';
diff --git a/packages/agent-core/src/mcp/oauth/store.ts b/packages/agent-core/src/mcp/oauth/store.ts
index 5c5e0720..c6a692c6 100644
--- a/packages/agent-core/src/mcp/oauth/store.ts
+++ b/packages/agent-core/src/mcp/oauth/store.ts
@@ -25,7 +25,7 @@ import {
   writeSync,
 } from 'node:fs';
 import { homedir } from 'node:os';
-import { basename, join } from 'node:path';
+import { basename, join } from 'pathe';
 
 export function mcpCredentialsDir(kimiHomeDir: string): string {
   return join(kimiHomeDir, 'credentials', 'mcp');
diff --git a/packages/agent-core/src/profile/context.ts b/packages/agent-core/src/profile/context.ts
index ba22806f..02004dcc 100644
--- a/packages/agent-core/src/profile/context.ts
+++ b/packages/agent-core/src/profile/context.ts
@@ -1,5 +1,4 @@
-import * as posixPath from 'node:path/posix';
-import * as win32Path from 'node:path/win32';
+import { dirname, join } from 'pathe';
 
 import type { Kaos } from '@moonshot-ai/kaos';
 
@@ -54,21 +53,21 @@ export async function loadAgentsMd(kaos: Kaos, workDir: string): Promise<string>
 
   // User-level files come first so any project-level AGENTS.md overrides them.
   const home = kaos.gethome();
-  await collect(joinPath(kaos, home, '.kimi-code', 'AGENTS.md'));
+  await collect(join(home, '.kimi-code', 'AGENTS.md'));
 
   // Generic user-level dir (.agents) matches skill discovery.
-  const genericDirs = [joinPath(kaos, home, '.agents')];
+  const genericDirs = [join(home, '.agents')];
   const genericFiles = genericDirs.flatMap((dir) =>
-    ['AGENTS.md', 'agents.md'].map((name) => joinPath(kaos, dir, name)),
+    ['AGENTS.md', 'agents.md'].map((name) => join(dir, name)),
   );
   for (const file of genericFiles) {
     if (await collect(file)) break;
   }
 
   for (const dir of dirs) {
-    await collect(joinPath(kaos, dir, '.kimi-code', 'AGENTS.md'));
+    await collect(join(dir, '.kimi-code', 'AGENTS.md'));
     for (const fileName of ['AGENTS.md', 'agents.md']) {
-      if (await collect(joinPath(kaos, dir, fileName))) break;
+      if (await collect(join(dir, fileName))) break;
     }
   }
 
@@ -76,27 +75,25 @@ export async function loadAgentsMd(kaos: Kaos, workDir: string): Promise<string>
 }
 
 async function findProjectRoot(kaos: Kaos, workDir: string): Promise<string> {
-  const path = pathMod(kaos);
   const initial = kaos.normpath(workDir);
   let current = initial;
 
   while (true) {
-    if (await pathExists(kaos, path.join(current, '.git'))) return current;
-    const parent = path.dirname(current);
+    if (await pathExists(kaos, join(current, '.git'))) return current;
+    const parent = dirname(current);
     if (parent === current) return initial;
     current = parent;
   }
 }
 
 function dirsRootToLeaf(kaos: Kaos, workDir: string, projectRoot: string): string[] {
-  const path = pathMod(kaos);
   const dirs: string[] = [];
   let current = kaos.normpath(workDir);
 
   while (true) {
     dirs.push(current);
     if (current === projectRoot) break;
-    const parent = path.dirname(current);
+    const parent = dirname(current);
     if (parent === current) break;
     current = parent;
   }
@@ -183,10 +180,4 @@ function annotationFor(path: string): string {
   return `<!-- From: ${path} -->\n`;
 }
 
-function joinPath(kaos: Kaos, ...parts: string[]): string {
-  return pathMod(kaos).join(...parts);
-}
 
-function pathMod(kaos: Kaos): typeof posixPath {
-  return kaos.pathClass() === 'win32' ? win32Path : posixPath;
-}
diff --git a/packages/agent-core/src/profile/load.ts b/packages/agent-core/src/profile/load.ts
index 613edcf6..7a258b2f 100644
--- a/packages/agent-core/src/profile/load.ts
+++ b/packages/agent-core/src/profile/load.ts
@@ -1,5 +1,5 @@
 import { readFile } from 'node:fs/promises';
-import { dirname, join, posix as posixPath } from 'node:path';
+import { dirname, join, normalize } from 'pathe';
 
 import { load as loadYaml } from 'js-yaml';
 
@@ -91,7 +91,7 @@ function parseAgentProfileYaml(content: string, profilePath: string): RawAgentPr
 
 function resolveProfileSourcePath(profilePath: string, relativePath: string): string {
   return normalizeSourcePath(
-    posixPath.join(posixPath.dirname(normalizeSourcePath(profilePath)), relativePath),
+    join(dirname(normalizeSourcePath(profilePath)), relativePath),
   );
 }
 
@@ -105,7 +105,7 @@ function readRequiredSource(sources: Readonly<Record<string, string>>, path: str
 }
 
 function normalizeSourcePath(path: string): string {
-  return posixPath.normalize(path.replaceAll('\\', '/')).replace(/^\.\//, '');
+  return normalize(path.replaceAll('\\', '/')).replace(/^\.\//, '');
 }
 
 function isRecord(value: unknown): value is Record<string, unknown> {
diff --git a/packages/agent-core/src/session/export/session-export.ts b/packages/agent-core/src/session/export/session-export.ts
index dc71b929..6f4d5e95 100644
--- a/packages/agent-core/src/session/export/session-export.ts
+++ b/packages/agent-core/src/session/export/session-export.ts
@@ -1,5 +1,5 @@
 import { readFile } from 'node:fs/promises';
-import { resolve } from 'node:path';
+import { resolve } from 'pathe';
 
 import { ErrorCodes, KimiError } from '#/errors';
 import { resolveGlobalLogPath } from '#/logging/logger';
diff --git a/packages/agent-core/src/session/export/wire-scan.ts b/packages/agent-core/src/session/export/wire-scan.ts
index 2d5aa2e2..7ae0c0ab 100644
--- a/packages/agent-core/src/session/export/wire-scan.ts
+++ b/packages/agent-core/src/session/export/wire-scan.ts
@@ -1,5 +1,5 @@
 import { readFile } from 'node:fs/promises';
-import { join } from 'node:path';
+import { join } from 'pathe';
 
 export interface SessionWireScan {
   readonly firstActivityMs?: number | undefined;
diff --git a/packages/agent-core/src/session/export/zip.ts b/packages/agent-core/src/session/export/zip.ts
index 295ac4a3..51507a28 100644
--- a/packages/agent-core/src/session/export/zip.ts
+++ b/packages/agent-core/src/session/export/zip.ts
@@ -1,6 +1,6 @@
 import { createWriteStream } from 'node:fs';
 import { mkdir, readdir, readFile } from 'node:fs/promises';
-import { dirname, join, relative } from 'node:path';
+import { dirname, join, relative } from 'pathe';
 import type { Readable } from 'node:stream';
 import { pipeline } from 'node:stream/promises';
 
diff --git a/packages/agent-core/src/session/index.ts b/packages/agent-core/src/session/index.ts
index 3fb9f778..b5bbe9a6 100644
--- a/packages/agent-core/src/session/index.ts
+++ b/packages/agent-core/src/session/index.ts
@@ -1,5 +1,5 @@
 import { homedir } from 'node:os';
-import { join } from 'node:path';
+import { join } from 'pathe';
 
 import { ErrorCodes, KimiError } from '#/errors';
 import { getRootLogger, log } from '#/logging/logger';
diff --git a/packages/agent-core/src/session/store/session-index.ts b/packages/agent-core/src/session/store/session-index.ts
index 6b77ed00..0753f4ec 100644
--- a/packages/agent-core/src/session/store/session-index.ts
+++ b/packages/agent-core/src/session/store/session-index.ts
@@ -1,5 +1,5 @@
 import { appendFile, mkdir, readFile } from 'node:fs/promises';
-import { basename, dirname, isAbsolute, join, relative, resolve } from 'node:path';
+import { basename, dirname, isAbsolute, join, relative, resolve } from 'pathe';
 
 export interface SessionIndexEntry {
   readonly sessionId: string;
diff --git a/packages/agent-core/src/session/store/session-store.ts b/packages/agent-core/src/session/store/session-store.ts
index 88a1bfcd..6c3965d7 100644
--- a/packages/agent-core/src/session/store/session-store.ts
+++ b/packages/agent-core/src/session/store/session-store.ts
@@ -1,5 +1,5 @@
 import { cp, mkdir, readdir, readFile, rm, stat, writeFile } from 'node:fs/promises';
-import { dirname, isAbsolute, join, relative } from 'node:path';
+import { dirname, isAbsolute, join, relative } from 'pathe';
 
 import { z } from 'zod';
 
diff --git a/packages/agent-core/src/session/store/workdir-key.ts b/packages/agent-core/src/session/store/workdir-key.ts
index 2b0aaafb..7b1c7f80 100644
--- a/packages/agent-core/src/session/store/workdir-key.ts
+++ b/packages/agent-core/src/session/store/workdir-key.ts
@@ -1,5 +1,5 @@
 import { createHash } from 'node:crypto';
-import { basename, resolve } from 'node:path';
+import { basename, resolve } from 'pathe';
 
 import { slugifyWorkDirName } from '#/utils/workdir-slug';
 
diff --git a/packages/agent-core/src/skill/parser.ts b/packages/agent-core/src/skill/parser.ts
index f308112b..cee0b953 100644
--- a/packages/agent-core/src/skill/parser.ts
+++ b/packages/agent-core/src/skill/parser.ts
@@ -1,5 +1,5 @@
 import { readFile } from 'node:fs/promises';
-import path from 'node:path';
+import path from 'pathe';
 
 import { load as loadYaml } from 'js-yaml';
 import regexpEscape from 'regexp.escape';
diff --git a/packages/agent-core/src/skill/scanner.ts b/packages/agent-core/src/skill/scanner.ts
index ecbe11b6..5f682393 100644
--- a/packages/agent-core/src/skill/scanner.ts
+++ b/packages/agent-core/src/skill/scanner.ts
@@ -1,5 +1,5 @@
 import { promises as fs } from 'node:fs';
-import path from 'node:path';
+import path from 'pathe';
 
 import { SkillParseError, UnsupportedSkillTypeError, parseSkillFromFile } from './parser';
 import type { SkillDefinition, SkillRoot, SkillSource, SkippedSkill } from './types';
@@ -52,7 +52,9 @@ export async function resolveSkillRoots(
   options: ResolveSkillRootsOptions,
 ): Promise<readonly SkillRoot[]> {
   const isDir = options.isDir ?? defaultIsDir;
-  const realpath = options.realpath ?? ((p: string) => fs.realpath(p));
+  const realpath =
+    options.realpath ??
+    ((p: string) => fs.realpath(p).then((r) => r.replaceAll('\\', '/')));
   const roots: SkillRoot[] = [];
   const mergeAllAvailableSkills = options.mergeAllAvailableSkills ?? true;
   const { userHomeDir, workDir } = options.paths;
diff --git a/packages/agent-core/src/tools/background/persist.ts b/packages/agent-core/src/tools/background/persist.ts
index bc4364e2..a6f95aa6 100644
--- a/packages/agent-core/src/tools/background/persist.ts
+++ b/packages/agent-core/src/tools/background/persist.ts
@@ -11,7 +11,7 @@
 
 import { statSync } from 'node:fs';
 import { appendFile, mkdir, open, readFile, readdir, rm, stat, unlink } from 'node:fs/promises';
-import { dirname, join } from 'node:path';
+import { dirname, join } from 'pathe';
 
 import { atomicWrite } from '../../utils/fs';
 import type { BackgroundTaskStatus } from './manager';
diff --git a/packages/agent-core/src/tools/builtin/file/glob.ts b/packages/agent-core/src/tools/builtin/file/glob.ts
index d58e37c5..3e67b214 100644
--- a/packages/agent-core/src/tools/builtin/file/glob.ts
+++ b/packages/agent-core/src/tools/builtin/file/glob.ts
@@ -29,6 +29,7 @@
  */
 
 import type { Kaos } from '@moonshot-ai/kaos';
+import { normalize } from 'pathe';
 import { z } from 'zod';
 
 import type { BuiltinTool } from '../../../agent/tool';
@@ -308,15 +309,16 @@ export class GlobTool implements BuiltinTool<GlobInput> {
  * should be canonical absolute paths.
  */
 function relativizeIfUnder(candidate: string, base: string, pathClass: PathClass): string {
-  const sep = pathClass === 'win32' ? '\\' : '/';
-  const comparableCandidate = pathClass === 'win32' ? candidate.toLowerCase() : candidate;
-  const comparableBase = pathClass === 'win32' ? base.toLowerCase() : base;
+  const normCandidate = normalize(candidate);
+  const normBase = normalize(base);
+  const comparableCandidate = pathClass === 'win32' ? normCandidate.toLowerCase() : normCandidate;
+  const comparableBase = pathClass === 'win32' ? normBase.toLowerCase() : normBase;
   if (comparableCandidate === comparableBase) return '.';
-  const prefix = comparableBase.endsWith(sep) ? comparableBase : comparableBase + sep;
+  const prefix = comparableBase.endsWith('/') ? comparableBase : comparableBase + '/';
   if (comparableCandidate.startsWith(prefix)) {
-    return candidate.slice(prefix.length);
+    return normCandidate.slice(prefix.length);
   }
-  return candidate;
+  return normCandidate;
 }
 
 // Return true iff `pattern` begins with the literal sequence `**` followed
diff --git a/packages/agent-core/src/tools/builtin/file/grep.ts b/packages/agent-core/src/tools/builtin/file/grep.ts
index 00dbcf25..0febb788 100644
--- a/packages/agent-core/src/tools/builtin/file/grep.ts
+++ b/packages/agent-core/src/tools/builtin/file/grep.ts
@@ -20,6 +20,7 @@
 import type { Readable } from 'node:stream';
 
 import type { Kaos, KaosProcess } from '@moonshot-ai/kaos';
+import { normalize } from 'pathe';
 import { z } from 'zod';
 
 import type { BuiltinTool } from '../../../agent/tool';
@@ -746,15 +747,16 @@ function formatDisplayLine(
  * canonical absolute paths in the active backend path class.
  */
 function relativizeIfUnder(candidate: string, base: string, pathClass: PathClass): string {
-  const sep = pathClass === 'win32' ? '\\' : '/';
-  const comparableCandidate = pathClass === 'win32' ? candidate.toLowerCase() : candidate;
-  const comparableBase = pathClass === 'win32' ? base.toLowerCase() : base;
+  const normCandidate = normalize(candidate);
+  const normBase = normalize(base);
+  const comparableCandidate = pathClass === 'win32' ? normCandidate.toLowerCase() : normCandidate;
+  const comparableBase = pathClass === 'win32' ? normBase.toLowerCase() : normBase;
   if (comparableCandidate === comparableBase) return '.';
-  const prefix = comparableBase.endsWith(sep) ? comparableBase : comparableBase + sep;
+  const prefix = comparableBase.endsWith('/') ? comparableBase : comparableBase + '/';
   if (comparableCandidate.startsWith(prefix)) {
-    return candidate.slice(prefix.length);
+    return normCandidate.slice(prefix.length);
   }
-  return candidate;
+  return normCandidate;
 }
 
 function omitIncompleteTrailingRecord(text: string, mode: GrepMode): string {
@@ -868,23 +870,23 @@ function parsedFilePath(
   mode: GrepMode,
   pathClass: PathClass,
 ): string | undefined {
-  if (line.kind === 'record') return line.filePath;
+  if (line.kind === 'record') return normalize(line.filePath);
   if (line.kind === 'separator') return undefined;
   const text = line.text;
-  if (mode === 'files_with_matches') return text;
+  if (mode === 'files_with_matches') return normalize(text);
   if (mode === 'count_matches') {
     const idx = text.lastIndexOf(':');
-    return idx > 0 ? text.slice(0, idx) : text;
+    return idx > 0 ? normalize(text.slice(0, idx)) : normalize(text);
   }
   return extractContentFilePath(text, pathClass);
 }
 
 function extractContentFilePath(line: string, pathClass: PathClass): string | undefined {
   const m = CONTENT_LINE_RE.exec(line);
-  if (m?.[1] !== undefined) return m[1];
+  if (m?.[1] !== undefined) return normalize(m[1]);
 
   const separatorIndex = noLineNumberContentSeparatorIndex(line, pathClass);
-  return separatorIndex > 0 ? line.slice(0, separatorIndex) : undefined;
+  return separatorIndex > 0 ? normalize(line.slice(0, separatorIndex)) : undefined;
 }
 
 function noLineNumberContentSeparatorIndex(line: string, pathClass: PathClass): number {
diff --git a/packages/agent-core/src/tools/builtin/file/write.ts b/packages/agent-core/src/tools/builtin/file/write.ts
index 59398007..647eb902 100644
--- a/packages/agent-core/src/tools/builtin/file/write.ts
+++ b/packages/agent-core/src/tools/builtin/file/write.ts
@@ -6,17 +6,13 @@
  */
 
 import type { Kaos } from '@moonshot-ai/kaos';
-import * as posixPath from 'node:path/posix';
-import * as win32Path from 'node:path/win32';
+import { dirname } from 'pathe';
 import { z } from 'zod';
 
 import type { BuiltinTool } from '../../../agent/tool';
 import { ToolAccesses } from '../../../loop/tool-access';
 import type { ExecutableToolResult, ToolExecution } from '../../../loop/types';
-import {
-  type PathClass,
-  resolvePathAccessPath,
-} from '../../policies/path-access';
+import { resolvePathAccessPath } from '../../policies/path-access';
 import { toInputJsonSchema } from '../../support/input-schema';
 import type { WorkspaceConfig } from '../../support/workspace';
 import WRITE_DESCRIPTION from './write.md';
@@ -26,10 +22,6 @@ const S_IFMT = 0o170000;
 /** File-type bits of a directory. */
 const S_IFDIR = 0o040000;
 
-function pathMod(pathClass: PathClass): typeof posixPath {
-  return pathClass === 'win32' ? win32Path : posixPath;
-}
-
 export const WriteInputSchema = z.object({
   path: z
     .string()
@@ -126,7 +118,7 @@ export class WriteTool implements BuiltinTool<WriteInput> {
    * skipped and the write proceeds, surfacing the real I/O error if any.
    */
   private async checkParentDirectory(safePath: string): Promise<string | undefined> {
-    const parent = pathMod(this.kaos.pathClass()).dirname(safePath);
+    const parent = dirname(safePath);
     let stat;
     try {
       stat = await this.kaos.stat(parent);
diff --git a/packages/agent-core/src/tools/policies/path-access.ts b/packages/agent-core/src/tools/policies/path-access.ts
index 00bcd4f9..f964d39a 100644
--- a/packages/agent-core/src/tools/policies/path-access.ts
+++ b/packages/agent-core/src/tools/policies/path-access.ts
@@ -12,9 +12,7 @@
  * `isWithinDirectory`.
  */
 
-import * as nativePath from 'node:path';
-import * as posixPath from 'node:path/posix';
-import * as win32Path from 'node:path/win32';
+import * as pathe from 'pathe';
 
 import type { Kaos } from '@moonshot-ai/kaos';
 
@@ -60,15 +58,7 @@ export class PathSecurityError extends Error {
   }
 }
 
-const DEFAULT_PATH_CLASS: PathClass = nativePath.sep === '\\' ? 'win32' : 'posix';
-
-function pathMod(pathClass: PathClass): typeof posixPath {
-  return pathClass === 'win32' ? win32Path : posixPath;
-}
-
-function comparablePath(path: string, pathClass: PathClass): string {
-  return pathClass === 'win32' ? path.toLowerCase().replaceAll('/', '\\') : path;
-}
+const DEFAULT_PATH_CLASS: PathClass = process.platform === 'win32' ? 'win32' : 'posix';
 
 function isWin32DriveRelative(path: string): boolean {
   return /^[A-Za-z]:(?:$|[^\\/])/.test(path);
@@ -77,27 +67,26 @@ function isWin32DriveRelative(path: string): boolean {
 export function normalizeUserPath(path: string, pathClass: PathClass = DEFAULT_PATH_CLASS): string {
   if (pathClass !== 'win32') return path;
 
-  // A bare root slash flips to backslash so downstream win32 string
-  // operations (join, isAbsolute, drive-letter detection) treat it as a
-  // native path component. Matches the py helper's behavior.
-  if (path === '/') return '\\';
+  // A bare root slash stays forward so downstream pathe operations
+  // treat it consistently. Matches the py helper's behavior.
+  if (path === '/') return '/';
 
   if (path.startsWith('//')) {
-    return path.replaceAll('/', '\\');
+    return path;
   }
 
   const cygdriveMatch = /^\/cygdrive\/([A-Za-z])(?:\/|$)/.exec(path);
   if (cygdriveMatch !== null) {
     const drive = cygdriveMatch[1]!.toUpperCase();
-    const rest = path.slice(`/cygdrive/${cygdriveMatch[1]!}`.length).replaceAll('/', '\\');
-    return `${drive}:${rest === '' ? '\\' : rest}`;
+    const rest = path.slice(`/cygdrive/${cygdriveMatch[1]!}`.length);
+    return `${drive}:${rest === '' ? '/' : rest}`;
   }
 
   const driveMatch = /^\/([A-Za-z])(?:\/|$)/.exec(path);
   if (driveMatch !== null) {
     const drive = driveMatch[1]!.toUpperCase();
-    const rest = path.slice(2).replaceAll('/', '\\');
-    return `${drive}:${rest === '' ? '\\' : rest}`;
+    const rest = path.slice(2);
+    return `${drive}:${rest === '' ? '/' : rest}`;
   }
 
   return path;
@@ -107,7 +96,7 @@ function expandUserPath(path: string, homeDir: string | undefined, pathClass: Pa
   if (homeDir === undefined) return path;
   if (path === '~') return homeDir;
   if (path.startsWith('~/') || (pathClass === 'win32' && path.startsWith('~\\'))) {
-    return pathMod(pathClass).join(homeDir, path.slice(2));
+    return pathe.join(homeDir, path.slice(2));
   }
   return path;
 }
@@ -124,7 +113,6 @@ export function canonicalizePath(
   if (path === '') {
     throw new PathSecurityError('PATH_INVALID', path, path, 'Path cannot be empty');
   }
-  const mod = pathMod(pathClass);
   const normalizedPath = normalizeUserPath(path, pathClass);
   if (pathClass === 'win32' && isWin32DriveRelative(normalizedPath)) {
     throw new PathSecurityError(
@@ -134,7 +122,7 @@ export function canonicalizePath(
       `"${path}" is a drive-relative Windows path. Use an absolute path like C:\\path or a path relative to the working directory.`,
     );
   }
-  if (!mod.isAbsolute(normalizedPath) && !mod.isAbsolute(cwd)) {
+  if (!pathe.isAbsolute(normalizedPath) && !pathe.isAbsolute(cwd)) {
     throw new PathSecurityError(
       'PATH_INVALID',
       path,
@@ -142,8 +130,8 @@ export function canonicalizePath(
       `Cannot resolve "${path}" against non-absolute cwd "${cwd}".`,
     );
   }
-  const abs = mod.isAbsolute(normalizedPath) ? normalizedPath : mod.resolve(cwd, normalizedPath);
-  return mod.normalize(abs);
+  const abs = pathe.isAbsolute(normalizedPath) ? normalizedPath : pathe.resolve(cwd, normalizedPath);
+  return pathe.normalize(abs);
 }
 
 /**
@@ -155,11 +143,12 @@ export function isWithinDirectory(
   base: string,
   pathClass: PathClass = DEFAULT_PATH_CLASS,
 ): boolean {
-  const mod = pathMod(pathClass);
-  const comparableCandidate = comparablePath(candidate, pathClass);
-  const comparableBase = comparablePath(base, pathClass);
+  const nc = pathe.normalize(candidate);
+  const nb = pathe.normalize(base);
+  const comparableCandidate = pathClass === 'win32' ? nc.toLowerCase() : nc;
+  const comparableBase = pathClass === 'win32' ? nb.toLowerCase() : nb;
   if (comparableCandidate === comparableBase) return true;
-  const prefix = comparableBase.endsWith(mod.sep) ? comparableBase : comparableBase + mod.sep;
+  const prefix = comparableBase.endsWith('/') ? comparableBase : comparableBase + '/';
   return comparableCandidate.startsWith(prefix);
 }
 
@@ -236,10 +225,9 @@ export function resolvePathAccess(
   options: ResolvePathAccessOptions,
 ): PathAccess {
   const pathClass = options.pathClass ?? DEFAULT_PATH_CLASS;
-  const mod = pathMod(pathClass);
   const normalizedPath = normalizeUserPath(path, pathClass);
   const expandedPath = expandUserPath(normalizedPath, options.homeDir, pathClass);
-  const rawIsAbsolute = mod.isAbsolute(expandedPath);
+  const rawIsAbsolute = pathe.isAbsolute(expandedPath);
   const canonical = canonicalizePath(expandedPath, cwd, pathClass);
   const outsideWorkspace = !isWithinWorkspace(canonical, config, pathClass);
   const policy = options.policy ?? DEFAULT_WORKSPACE_ACCESS_POLICY;
diff --git a/packages/agent-core/src/tools/policies/sensitive.ts b/packages/agent-core/src/tools/policies/sensitive.ts
index 6557488f..607896a8 100644
--- a/packages/agent-core/src/tools/policies/sensitive.ts
+++ b/packages/agent-core/src/tools/policies/sensitive.ts
@@ -7,9 +7,7 @@
  * like `.env.example` are explicitly allowed.
  */
 
-import * as nativePath from 'node:path';
-import * as posixPath from 'node:path/posix';
-import * as win32Path from 'node:path/win32';
+import { basename } from 'pathe';
 
 import type { PathClass } from './path-access';
 
@@ -45,19 +43,14 @@ export const SENSITIVE_DOT_VARIANT_SUFFIXES = [
 ] as const;
 const SENSITIVE_DOT_VARIANT_SUFFIX_SET = new Set<string>(SENSITIVE_DOT_VARIANT_SUFFIXES);
 
-const DEFAULT_PATH_CLASS: PathClass = nativePath.sep === '\\' ? 'win32' : 'posix';
-
-function pathMod(pathClass: PathClass): typeof posixPath {
-  return pathClass === 'win32' ? win32Path : posixPath;
-}
+const DEFAULT_PATH_CLASS: PathClass = process.platform === 'win32' ? 'win32' : 'posix';
 
 function comparable(path: string, pathClass: PathClass): string {
   return pathClass === 'win32' ? path.toLowerCase() : path;
 }
 
 export function isSensitiveFile(path: string, pathClass: PathClass = DEFAULT_PATH_CLASS): boolean {
-  const mod = pathMod(pathClass);
-  const name = mod.basename(path);
+  const name = basename(path);
   const comparableName = comparable(name, pathClass);
   const comparablePath = comparable(path, pathClass);
 
@@ -79,11 +72,11 @@ export function isSensitiveFile(path: string, pathClass: PathClass = DEFAULT_PAT
   }
 
   for (const suffixParts of SENSITIVE_PATH_SUFFIXES) {
-    const suffix = suffixParts.join(mod.sep);
+    const suffix = suffixParts.join('/');
     const comparableSuffix = comparable(suffix, pathClass);
     if (
-      comparablePath.endsWith(`${mod.sep}${comparableSuffix}`) ||
-      comparablePath.includes(`${mod.sep}${comparableSuffix}${mod.sep}`)
+      comparablePath.endsWith(`/${comparableSuffix}`) ||
+      comparablePath.includes(`/${comparableSuffix}/`)
     ) {
       return true;
     }
diff --git a/packages/agent-core/src/tools/support/git-worktree.ts b/packages/agent-core/src/tools/support/git-worktree.ts
index fedf55e1..61dd85a6 100644
--- a/packages/agent-core/src/tools/support/git-worktree.ts
+++ b/packages/agent-core/src/tools/support/git-worktree.ts
@@ -3,13 +3,10 @@
  * null so callers can fall back to their safer path.
  */
 
-import * as posixPath from 'node:path/posix';
-import * as win32Path from 'node:path/win32';
+import * as pathe from 'pathe';
 
 import type { Kaos } from '@moonshot-ai/kaos';
 
-import type { PathClass } from '../policies/path-access';
-
 const S_IFMT = 0o170000;
 const S_IFDIR = 0o040000;
 const S_IFREG = 0o100000;
@@ -19,25 +16,19 @@ export interface GitWorkTreeMarker {
   readonly controlDirPath: string;
 }
 
-function pathMod(pathClass: PathClass): typeof posixPath {
-  return pathClass === 'win32' ? win32Path : posixPath;
-}
-
 export async function findGitWorkTreeMarker(
   kaos: Kaos,
   cwd: string,
 ): Promise<GitWorkTreeMarker | null> {
-  const pathClass = kaos.pathClass();
-  const mod = pathMod(pathClass);
-  if (cwd.length === 0 || !mod.isAbsolute(cwd)) return null;
+  if (cwd.length === 0 || !pathe.isAbsolute(cwd)) return null;
 
-  let current = mod.normalize(cwd);
+  let current = pathe.normalize(cwd);
   for (let depth = 0; depth < 256; depth += 1) {
-    const dotGitPath = mod.join(current, '.git');
-    const hit = await probeGitMarker(kaos, dotGitPath, current, pathClass);
+    const dotGitPath = pathe.join(current, '.git');
+    const hit = await probeGitMarker(kaos, dotGitPath, current);
     if (hit !== null) return hit;
 
-    const parent = mod.dirname(current);
+    const parent = pathe.dirname(current);
     if (parent === current) return null;
     current = parent;
   }
@@ -48,7 +39,6 @@ async function probeGitMarker(
   kaos: Kaos,
   dotGitPath: string,
   markerParent: string,
-  pathClass: PathClass,
 ): Promise<GitWorkTreeMarker | null> {
   let stat: Awaited<ReturnType<Kaos['stat']>>;
   try {
@@ -66,7 +56,7 @@ async function probeGitMarker(
   } catch {
     return null;
   }
-  const controlDirPath = parseGitDir(content, markerParent, pathClass);
+  const controlDirPath = parseGitDir(content, markerParent);
   return controlDirPath === undefined ? null : { dotGitPath, controlDirPath };
 }
 
@@ -84,7 +74,6 @@ function stripLeadingNoise(content: string): string {
 function parseGitDir(
   content: string,
   markerParent: string,
-  pathClass: PathClass,
 ): string | undefined {
   const line = stripLeadingNoise(content).split(/\r?\n/, 1)[0]?.trim();
   if (line === undefined || !line.startsWith('gitdir:')) return undefined;
@@ -92,7 +81,6 @@ function parseGitDir(
   const rawPath = line.slice('gitdir:'.length).trim();
   if (rawPath.length === 0) return undefined;
 
-  const mod = pathMod(pathClass);
-  const absolute = mod.isAbsolute(rawPath) ? rawPath : mod.join(markerParent, rawPath);
-  return mod.normalize(absolute);
+  const absolute = pathe.isAbsolute(rawPath) ? rawPath : pathe.join(markerParent, rawPath);
+  return pathe.normalize(absolute);
 }
diff --git a/packages/agent-core/src/tools/support/list-directory.ts b/packages/agent-core/src/tools/support/list-directory.ts
index 433aa9f6..88402456 100644
--- a/packages/agent-core/src/tools/support/list-directory.ts
+++ b/packages/agent-core/src/tools/support/list-directory.ts
@@ -11,16 +11,13 @@
  *   - Truncated levels show "... and N more" so the LLM knows more exists.
  */
 
-import * as posixPath from 'node:path/posix';
-import * as win32Path from 'node:path/win32';
+import { basename, join } from 'pathe';
 
 import type { Kaos } from '@moonshot-ai/kaos';
 
 export const LIST_DIR_ROOT_WIDTH = 30;
 export const LIST_DIR_CHILD_WIDTH = 10;
 
-type PathClass = 'posix' | 'win32';
-
 interface Entry {
   readonly name: string;
   readonly isDir: boolean;
@@ -30,12 +27,11 @@ async function collectEntries(
   kaos: Kaos,
   dirPath: string,
   maxWidth: number,
-  pathClass: PathClass,
 ): Promise<{ entries: Entry[]; total: number; readable: boolean }> {
   const all: Entry[] = [];
   try {
     for await (const fullPath of kaos.iterdir(dirPath)) {
-      const name = basename(fullPath, pathClass);
+      const name = basename(fullPath);
       let isDir = false;
       try {
         const st = await kaos.stat(fullPath);
@@ -57,14 +53,6 @@ async function collectEntries(
   return { entries: all.slice(0, maxWidth), total: all.length, readable: true };
 }
 
-function pathMod(pathClass: PathClass): typeof posixPath {
-  return pathClass === 'win32' ? win32Path : posixPath;
-}
-
-function basename(p: string, pathClass: PathClass): string {
-  return pathMod(pathClass).basename(p);
-}
-
 /**
  * Return a 2-level tree listing of `workDir` suitable for inclusion in a
  * tool error message. Returns `"(empty directory)"` if the directory is
@@ -72,12 +60,10 @@ function basename(p: string, pathClass: PathClass): string {
  */
 export async function listDirectory(kaos: Kaos, workDir: string): Promise<string> {
   const lines: string[] = [];
-  const pathClass = kaos.pathClass();
   const { entries, total, readable } = await collectEntries(
     kaos,
     workDir,
     LIST_DIR_ROOT_WIDTH,
-    pathClass,
   );
   if (!readable) return '[not readable]';
   const remaining = total - entries.length;
@@ -92,8 +78,8 @@ export async function listDirectory(kaos: Kaos, workDir: string): Promise<string
     if (isDir) {
       lines.push(`${connector}${name}/`);
       const childPrefix = isLast ? '    ' : '│   ';
-      const childDir = joinPath(workDir, name, pathClass);
-      const child = await collectEntries(kaos, childDir, LIST_DIR_CHILD_WIDTH, pathClass);
+      const childDir = join(workDir, name);
+      const child = await collectEntries(kaos, childDir, LIST_DIR_CHILD_WIDTH);
       if (!child.readable) {
         lines.push(`${childPrefix}└── [not readable]`);
         continue;
@@ -122,6 +108,4 @@ export async function listDirectory(kaos: Kaos, workDir: string): Promise<string
   return lines.length > 0 ? lines.join('\n') : '(empty directory)';
 }
 
-function joinPath(parent: string, child: string, pathClass: PathClass): string {
-  return pathMod(pathClass).join(parent, child);
-}
+
diff --git a/packages/agent-core/src/tools/support/rg-locator.ts b/packages/agent-core/src/tools/support/rg-locator.ts
index a551c908..f8b0ec00 100644
--- a/packages/agent-core/src/tools/support/rg-locator.ts
+++ b/packages/agent-core/src/tools/support/rg-locator.ts
@@ -16,7 +16,7 @@ import { createHash } from 'node:crypto';
 import { createWriteStream, existsSync } from 'node:fs';
 import { chmod, mkdir, mkdtemp, readFile, rename, rm, stat } from 'node:fs/promises';
 import { homedir, tmpdir } from 'node:os';
-import { basename, join } from 'node:path';
+import { basename, join } from 'pathe';
 import { Readable } from 'node:stream';
 import { pipeline } from 'node:stream/promises';
 
diff --git a/packages/agent-core/src/utils/fs.ts b/packages/agent-core/src/utils/fs.ts
index 79aef2e4..7d4566aa 100644
--- a/packages/agent-core/src/utils/fs.ts
+++ b/packages/agent-core/src/utils/fs.ts
@@ -18,7 +18,7 @@ import { randomBytes } from 'node:crypto';
 import { closeSync, fsyncSync, openSync } from 'node:fs';
 import * as nodeFs from 'node:fs';
 import { open, rename, unlink } from 'node:fs/promises';
-import { dirname } from 'node:path';
+import { dirname } from 'pathe';
 
 /**
  * Open a directory read-only and fsync it, then close. Used to make a
diff --git a/packages/agent-core/test/agent/background-manager.test.ts b/packages/agent-core/test/agent/background-manager.test.ts
index 882fb901..680c26a1 100644
--- a/packages/agent-core/test/agent/background-manager.test.ts
+++ b/packages/agent-core/test/agent/background-manager.test.ts
@@ -8,7 +8,7 @@
 
 import { mkdtemp, rm } from 'node:fs/promises';
 import { tmpdir } from 'node:os';
-import { join } from 'node:path';
+import { join } from 'pathe';
 import { Readable } from 'node:stream';
 import type { Writable } from 'node:stream';
 
diff --git a/packages/agent-core/test/agent/compaction.test.ts b/packages/agent-core/test/agent/compaction.test.ts
index c0bf6546..93723995 100644
--- a/packages/agent-core/test/agent/compaction.test.ts
+++ b/packages/agent-core/test/agent/compaction.test.ts
@@ -1,6 +1,6 @@
 import { existsSync, mkdtempSync, readFileSync } from 'node:fs';
 import { tmpdir } from 'node:os';
-import { join } from 'node:path';
+import { join } from 'pathe';
 
 import {
   APIConnectionError,
diff --git a/packages/agent-core/test/agent/records/persistence.test.ts b/packages/agent-core/test/agent/records/persistence.test.ts
index 3f89634b..701515e0 100644
--- a/packages/agent-core/test/agent/records/persistence.test.ts
+++ b/packages/agent-core/test/agent/records/persistence.test.ts
@@ -1,7 +1,7 @@
 import { randomBytes } from 'node:crypto';
 import { mkdir, readFile, rm } from 'node:fs/promises';
 import { tmpdir } from 'node:os';
-import { join } from 'node:path';
+import { join } from 'pathe';
 
 import { afterEach, describe, expect, it } from 'vitest';
 
diff --git a/packages/agent-core/test/agent/resume.test.ts b/packages/agent-core/test/agent/resume.test.ts
index f116b25f..a3ad386c 100644
--- a/packages/agent-core/test/agent/resume.test.ts
+++ b/packages/agent-core/test/agent/resume.test.ts
@@ -1,6 +1,6 @@
 import { mkdtemp, rm } from 'node:fs/promises';
 import { tmpdir } from 'node:os';
-import { join } from 'node:path';
+import { join } from 'pathe';
 
 import { describe, expect, it, vi } from 'vitest';
 
diff --git a/packages/agent-core/test/agent/skill-tool-manager.test.ts b/packages/agent-core/test/agent/skill-tool-manager.test.ts
index dd48a161..af90c73c 100644
--- a/packages/agent-core/test/agent/skill-tool-manager.test.ts
+++ b/packages/agent-core/test/agent/skill-tool-manager.test.ts
@@ -1,6 +1,6 @@
 import { mkdtemp, mkdir, rm, writeFile } from 'node:fs/promises';
 import { tmpdir } from 'node:os';
-import { join } from 'node:path';
+import { join } from 'pathe';
 
 import { localKaos } from '@moonshot-ai/kaos';
 import { describe, expect, it, vi } from 'vitest';
diff --git a/packages/agent-core/test/agent/turn.test.ts b/packages/agent-core/test/agent/turn.test.ts
index 8ef9c26e..6da4f8f6 100644
--- a/packages/agent-core/test/agent/turn.test.ts
+++ b/packages/agent-core/test/agent/turn.test.ts
@@ -1,6 +1,6 @@
 import { existsSync, mkdtempSync } from 'node:fs';
 import { tmpdir } from 'node:os';
-import { join } from 'node:path';
+import { join } from 'pathe';
 import { setTimeout as delay } from 'node:timers/promises';
 
 import type { Kaos } from '@moonshot-ai/kaos';
diff --git a/packages/agent-core/test/config/configs.test.ts b/packages/agent-core/test/config/configs.test.ts
index 7d118cbe..aeea428c 100644
--- a/packages/agent-core/test/config/configs.test.ts
+++ b/packages/agent-core/test/config/configs.test.ts
@@ -1,7 +1,7 @@
 import { mkdtempSync } from 'node:fs';
 import { readFile, rm, writeFile } from 'node:fs/promises';
 import { tmpdir } from 'node:os';
-import { join } from 'node:path';
+import { join } from 'pathe';
 
 import { afterEach, describe, expect, it } from 'vitest';
 
diff --git a/packages/agent-core/test/harness/model-alias-session.test.ts b/packages/agent-core/test/harness/model-alias-session.test.ts
index 1113937d..b808e076 100644
--- a/packages/agent-core/test/harness/model-alias-session.test.ts
+++ b/packages/agent-core/test/harness/model-alias-session.test.ts
@@ -1,6 +1,6 @@
 import { mkdtemp, mkdir, readdir, readFile, rm, writeFile } from 'node:fs/promises';
 import { tmpdir } from 'node:os';
-import { join } from 'node:path';
+import { join } from 'pathe';
 
 import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest';
 
diff --git a/packages/agent-core/test/harness/plan-mode-session.test.ts b/packages/agent-core/test/harness/plan-mode-session.test.ts
index bbd57855..44c6e860 100644
--- a/packages/agent-core/test/harness/plan-mode-session.test.ts
+++ b/packages/agent-core/test/harness/plan-mode-session.test.ts
@@ -1,6 +1,6 @@
 import { mkdtemp, mkdir, readdir, readFile, rm, writeFile } from 'node:fs/promises';
 import { tmpdir } from 'node:os';
-import { join } from 'node:path';
+import { join } from 'pathe';
 
 import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest';
 
diff --git a/packages/agent-core/test/harness/runtime.test.ts b/packages/agent-core/test/harness/runtime.test.ts
index 2e272bb9..478d3de1 100644
--- a/packages/agent-core/test/harness/runtime.test.ts
+++ b/packages/agent-core/test/harness/runtime.test.ts
@@ -1,6 +1,6 @@
 import { mkdir, mkdtemp, rm, writeFile } from 'node:fs/promises';
 import { tmpdir } from 'node:os';
-import { join } from 'node:path';
+import { join } from 'pathe';
 
 import { afterEach, describe, expect, it, vi } from 'vitest';
 
diff --git a/packages/agent-core/test/harness/skill-session.test.ts b/packages/agent-core/test/harness/skill-session.test.ts
index 6c20abd7..ac6be2b4 100644
--- a/packages/agent-core/test/harness/skill-session.test.ts
+++ b/packages/agent-core/test/harness/skill-session.test.ts
@@ -1,6 +1,6 @@
 import { mkdtemp, mkdir, readFile, realpath, rm, writeFile } from 'node:fs/promises';
 import { tmpdir } from 'node:os';
-import { join } from 'node:path';
+import { join } from 'pathe';
 import { setTimeout as delay } from 'node:timers/promises';
 
 import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest';
diff --git a/packages/agent-core/test/hooks/integration.test.ts b/packages/agent-core/test/hooks/integration.test.ts
index 365dd879..d6e56f99 100644
--- a/packages/agent-core/test/hooks/integration.test.ts
+++ b/packages/agent-core/test/hooks/integration.test.ts
@@ -1,6 +1,6 @@
 import { mkdtempSync, writeFileSync, chmodSync } from 'node:fs';
 import { tmpdir } from 'node:os';
-import { join } from 'node:path';
+import { join } from 'pathe';
 
 import type { ContentPart } from '@moonshot-ai/kosong';
 import { describe, expect, it } from 'vitest';
diff --git a/packages/agent-core/test/logging/logger.test.ts b/packages/agent-core/test/logging/logger.test.ts
index 4ef8a33d..ed068704 100644
--- a/packages/agent-core/test/logging/logger.test.ts
+++ b/packages/agent-core/test/logging/logger.test.ts
@@ -1,6 +1,6 @@
 import { mkdtemp, readFile, rm } from 'node:fs/promises';
 import { tmpdir } from 'node:os';
-import { join } from 'node:path';
+import { join } from 'pathe';
 
 import { afterEach, beforeEach, describe, expect, it } from 'vitest';
 
diff --git a/packages/agent-core/test/logging/sinks.test.ts b/packages/agent-core/test/logging/sinks.test.ts
index bb7a24b7..48a199f2 100644
--- a/packages/agent-core/test/logging/sinks.test.ts
+++ b/packages/agent-core/test/logging/sinks.test.ts
@@ -1,6 +1,6 @@
 import { mkdtemp, readFile, readdir, rm, stat } from 'node:fs/promises';
 import { tmpdir } from 'node:os';
-import { join } from 'node:path';
+import { join } from 'pathe';
 
 import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest';
 
diff --git a/packages/agent-core/test/mcp/client-stdio.test.ts b/packages/agent-core/test/mcp/client-stdio.test.ts
index 854c4644..150b7a96 100644
--- a/packages/agent-core/test/mcp/client-stdio.test.ts
+++ b/packages/agent-core/test/mcp/client-stdio.test.ts
@@ -1,4 +1,4 @@
-import { dirname, join } from 'node:path';
+import { dirname, join } from 'pathe';
 import { fileURLToPath } from 'node:url';
 
 import { describe, expect, it } from 'vitest';
diff --git a/packages/agent-core/test/mcp/config-loader.test.ts b/packages/agent-core/test/mcp/config-loader.test.ts
index 558d1ac9..a6b3313e 100644
--- a/packages/agent-core/test/mcp/config-loader.test.ts
+++ b/packages/agent-core/test/mcp/config-loader.test.ts
@@ -1,7 +1,7 @@
 import { mkdtempSync } from 'node:fs';
 import { mkdir, rm, writeFile } from 'node:fs/promises';
 import { tmpdir } from 'node:os';
-import { join } from 'node:path';
+import { join } from 'pathe';
 
 import { afterEach, describe, expect, it } from 'vitest';
 
diff --git a/packages/agent-core/test/mcp/connection-manager.test.ts b/packages/agent-core/test/mcp/connection-manager.test.ts
index 7e77b41b..27fa427d 100644
--- a/packages/agent-core/test/mcp/connection-manager.test.ts
+++ b/packages/agent-core/test/mcp/connection-manager.test.ts
@@ -1,6 +1,6 @@
 import { mkdtemp, readFile, rm } from 'node:fs/promises';
 import { tmpdir } from 'node:os';
-import { dirname, join } from 'node:path';
+import { dirname, join } from 'pathe';
 import { setTimeout as sleep } from 'node:timers/promises';
 import { fileURLToPath, pathToFileURL } from 'node:url';
 
diff --git a/packages/agent-core/test/mcp/oauth-store.test.ts b/packages/agent-core/test/mcp/oauth-store.test.ts
index 38dbc338..2d3b5072 100644
--- a/packages/agent-core/test/mcp/oauth-store.test.ts
+++ b/packages/agent-core/test/mcp/oauth-store.test.ts
@@ -1,6 +1,6 @@
 import { mkdtemp, rm, stat } from 'node:fs/promises';
 import { tmpdir } from 'node:os';
-import { join } from 'node:path';
+import { join } from 'pathe';
 
 import { afterEach, beforeEach, describe, expect, it } from 'vitest';
 
diff --git a/packages/agent-core/test/profile/agent-profile-loader.test.ts b/packages/agent-core/test/profile/agent-profile-loader.test.ts
index 963af54e..fb4e7283 100644
--- a/packages/agent-core/test/profile/agent-profile-loader.test.ts
+++ b/packages/agent-core/test/profile/agent-profile-loader.test.ts
@@ -1,6 +1,6 @@
 import { mkdtemp, rm, writeFile } from 'node:fs/promises';
 import { tmpdir } from 'node:os';
-import { join } from 'node:path';
+import { join } from 'pathe';
 
 import { afterEach, beforeEach, describe, expect, it } from 'vitest';
 
diff --git a/packages/agent-core/test/profile/context.test.ts b/packages/agent-core/test/profile/context.test.ts
index e7449969..2b9541f5 100644
--- a/packages/agent-core/test/profile/context.test.ts
+++ b/packages/agent-core/test/profile/context.test.ts
@@ -1,6 +1,6 @@
 import { mkdir, mkdtemp, rm, writeFile } from 'node:fs/promises';
 import { tmpdir } from 'node:os';
-import { join } from 'node:path';
+import { join } from 'pathe';
 
 import { localKaos } from '@moonshot-ai/kaos';
 import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest';
diff --git a/packages/agent-core/test/prompt-placeholders.test.ts b/packages/agent-core/test/prompt-placeholders.test.ts
index dcfe13d8..eee21b85 100644
--- a/packages/agent-core/test/prompt-placeholders.test.ts
+++ b/packages/agent-core/test/prompt-placeholders.test.ts
@@ -1,5 +1,5 @@
 import { globSync, readFileSync } from 'node:fs';
-import { join } from 'node:path';
+import { join } from 'pathe';
 
 import { describe, expect, it } from 'vitest';
 
diff --git a/packages/agent-core/test/session/init.test.ts b/packages/agent-core/test/session/init.test.ts
index 8320daf4..7da47914 100644
--- a/packages/agent-core/test/session/init.test.ts
+++ b/packages/agent-core/test/session/init.test.ts
@@ -1,6 +1,6 @@
 import { mkdir, mkdtemp, rm, writeFile } from 'node:fs/promises';
 import { tmpdir } from 'node:os';
-import { dirname, join } from 'node:path';
+import { dirname, join } from 'pathe';
 import { fileURLToPath } from 'node:url';
 
 import { localKaos } from '@moonshot-ai/kaos';
diff --git a/packages/agent-core/test/session/lifecycle-hooks.test.ts b/packages/agent-core/test/session/lifecycle-hooks.test.ts
index a58a6195..bd6e4570 100644
--- a/packages/agent-core/test/session/lifecycle-hooks.test.ts
+++ b/packages/agent-core/test/session/lifecycle-hooks.test.ts
@@ -1,6 +1,6 @@
 import { mkdir, mkdtemp, readFile, rm, writeFile } from 'node:fs/promises';
 import { tmpdir } from 'node:os';
-import { join } from 'node:path';
+import { join } from 'pathe';
 import { Readable } from 'node:stream';
 import type { Writable } from 'node:stream';
 
diff --git a/packages/agent-core/test/session/subagent-host.test.ts b/packages/agent-core/test/session/subagent-host.test.ts
index a1a6c068..6a411081 100644
--- a/packages/agent-core/test/session/subagent-host.test.ts
+++ b/packages/agent-core/test/session/subagent-host.test.ts
@@ -1,6 +1,6 @@
 import { mkdir, mkdtemp, rm, writeFile } from 'node:fs/promises';
 import { tmpdir } from 'node:os';
-import { join } from 'node:path';
+import { join } from 'pathe';
 
 import { localKaos } from '@moonshot-ai/kaos';
 import type { ToolCall } from '@moonshot-ai/kosong';
diff --git a/packages/agent-core/test/skill/parser.test.ts b/packages/agent-core/test/skill/parser.test.ts
index 11b868ce..15d105fb 100644
--- a/packages/agent-core/test/skill/parser.test.ts
+++ b/packages/agent-core/test/skill/parser.test.ts
@@ -1,6 +1,6 @@
 import { mkdtemp, mkdir, rm, writeFile } from 'node:fs/promises';
 import { tmpdir } from 'node:os';
-import path from 'node:path';
+import path from 'pathe';
 
 import { afterEach, describe, expect, it } from 'vitest';
 
diff --git a/packages/agent-core/test/skill/scanner.test.ts b/packages/agent-core/test/skill/scanner.test.ts
index 41d60569..12a5bde6 100644
--- a/packages/agent-core/test/skill/scanner.test.ts
+++ b/packages/agent-core/test/skill/scanner.test.ts
@@ -1,6 +1,6 @@
 import { mkdtemp, mkdir, realpath, rm, symlink, writeFile } from 'node:fs/promises';
 import { tmpdir } from 'node:os';
-import path from 'node:path';
+import path from 'pathe';
 
 import { afterEach, describe, expect, it } from 'vitest';
 
diff --git a/packages/agent-core/test/tools/background/heartbeat-stale.test.ts b/packages/agent-core/test/tools/background/heartbeat-stale.test.ts
index ef22ab47..d2a444d7 100644
--- a/packages/agent-core/test/tools/background/heartbeat-stale.test.ts
+++ b/packages/agent-core/test/tools/background/heartbeat-stale.test.ts
@@ -14,7 +14,7 @@
 
 import { mkdir, rm } from 'node:fs/promises';
 import { tmpdir } from 'node:os';
-import { join } from 'node:path';
+import { join } from 'pathe';
 
 import { afterEach, beforeEach, describe, expect, it } from 'vitest';
 
diff --git a/packages/agent-core/test/tools/background/lifecycle.test.ts b/packages/agent-core/test/tools/background/lifecycle.test.ts
index 806a278d..1f8a8a6f 100644
--- a/packages/agent-core/test/tools/background/lifecycle.test.ts
+++ b/packages/agent-core/test/tools/background/lifecycle.test.ts
@@ -12,7 +12,7 @@
 
 import { mkdtempSync, rmSync, writeFileSync, mkdirSync } from 'node:fs';
 import { tmpdir } from 'node:os';
-import { join } from 'node:path';
+import { join } from 'pathe';
 import { Readable } from 'node:stream';
 import type { Writable } from 'node:stream';
 
diff --git a/packages/agent-core/test/tools/background/manager.test.ts b/packages/agent-core/test/tools/background/manager.test.ts
index b7fb74a2..9e3210d5 100644
--- a/packages/agent-core/test/tools/background/manager.test.ts
+++ b/packages/agent-core/test/tools/background/manager.test.ts
@@ -7,7 +7,7 @@
 
 import { mkdtemp, rm } from 'node:fs/promises';
 import { tmpdir } from 'node:os';
-import { join } from 'node:path';
+import { join } from 'pathe';
 import { Readable } from 'node:stream';
 import type { Writable } from 'node:stream';
 
diff --git a/packages/agent-core/test/tools/background/output-access.test.ts b/packages/agent-core/test/tools/background/output-access.test.ts
index 1e55ef6d..3d91e91f 100644
--- a/packages/agent-core/test/tools/background/output-access.test.ts
+++ b/packages/agent-core/test/tools/background/output-access.test.ts
@@ -11,7 +11,7 @@
 
 import { mkdtempSync, rmSync } from 'node:fs';
 import { tmpdir } from 'node:os';
-import { join } from 'node:path';
+import { join } from 'pathe';
 import { Readable } from 'node:stream';
 import type { Writable } from 'node:stream';
 
diff --git a/packages/agent-core/test/tools/background/persist.test.ts b/packages/agent-core/test/tools/background/persist.test.ts
index cc33fa63..172adcdf 100644
--- a/packages/agent-core/test/tools/background/persist.test.ts
+++ b/packages/agent-core/test/tools/background/persist.test.ts
@@ -4,7 +4,7 @@
 
 import { mkdir, rm, stat } from 'node:fs/promises';
 import { tmpdir } from 'node:os';
-import { join } from 'node:path';
+import { join } from 'pathe';
 
 import { afterEach, beforeEach, describe, expect, it } from 'vitest';
 
diff --git a/packages/agent-core/test/tools/background/reconcile.test.ts b/packages/agent-core/test/tools/background/reconcile.test.ts
index dd24e48f..b2e69072 100644
--- a/packages/agent-core/test/tools/background/reconcile.test.ts
+++ b/packages/agent-core/test/tools/background/reconcile.test.ts
@@ -4,7 +4,7 @@
 
 import { mkdir, rm } from 'node:fs/promises';
 import { tmpdir } from 'node:os';
-import { join } from 'node:path';
+import { join } from 'pathe';
 
 import { afterEach, beforeEach, describe, expect, it } from 'vitest';
 
diff --git a/packages/agent-core/test/tools/background/task-tools.test.ts b/packages/agent-core/test/tools/background/task-tools.test.ts
index d2d465bc..30b07993 100644
--- a/packages/agent-core/test/tools/background/task-tools.test.ts
+++ b/packages/agent-core/test/tools/background/task-tools.test.ts
@@ -6,7 +6,7 @@
 
 import { mkdtemp, rm } from 'node:fs/promises';
 import { tmpdir } from 'node:os';
-import { join } from 'node:path';
+import { join } from 'pathe';
 import { Readable } from 'node:stream';
 import type { Writable } from 'node:stream';
 
diff --git a/packages/agent-core/test/tools/glob.test.ts b/packages/agent-core/test/tools/glob.test.ts
index 8cb4c270..c0d5091f 100644
--- a/packages/agent-core/test/tools/glob.test.ts
+++ b/packages/agent-core/test/tools/glob.test.ts
@@ -92,8 +92,8 @@ describe('GlobTool', () => {
 
     const result = await executeTool(tool, context({ pattern: 'src/**/*.ts', path: 'C:\\WORKSPACE' }));
 
-    expect(result.output).toBe('src\\old.ts');
-    expect(glob).toHaveBeenCalledWith('C:\\WORKSPACE', 'src/**/*.ts');
+    expect(result.output).toBe('src/old.ts');
+    expect(glob).toHaveBeenCalledWith('C:/WORKSPACE', 'src/**/*.ts');
   });
 
   it('rejects pure wildcard patterns before walking the tree', async () => {
diff --git a/packages/agent-core/test/tools/grep.test.ts b/packages/agent-core/test/tools/grep.test.ts
index b31931d5..3c5ca2b8 100644
--- a/packages/agent-core/test/tools/grep.test.ts
+++ b/packages/agent-core/test/tools/grep.test.ts
@@ -797,7 +797,7 @@ describe('GrepTool', () => {
 
     const result = await executeTool(tool, context({ pattern: 'hit', output_mode: 'content' }));
 
-    expect(result.output).toContain('src\\main.ts:10:hit');
+    expect(result.output).toContain('src/main.ts:10:hit');
     expect(result.output).not.toContain('SECRET=hit');
     expect(result.output).toContain('Filtered 1 sensitive file(s): .env');
   });
@@ -830,7 +830,7 @@ describe('GrepTool', () => {
       'C:\\workspace',
     );
     expect(toolContentString(result)).toBe(
-      ['src\\main.ts:hit', 'Filtered 1 sensitive file(s): .aws\\credentials'].join('\n'),
+      ['src/main.ts:hit', 'Filtered 1 sensitive file(s): .aws/credentials'].join('\n'),
     );
   });
 
@@ -849,7 +849,7 @@ describe('GrepTool', () => {
     const result = await executeTool(tool, context({ pattern: 'hit', output_mode: 'content' }));
 
     expect(toolContentString(result)).toBe(
-      ['src\\main.ts:1:hit', 'Filtered 1 sensitive file(s): foo-10-\\.aws\\credentials'].join('\n'),
+      ['src/main.ts:1:hit', 'Filtered 1 sensitive file(s): foo-10-/.aws/credentials'].join('\n'),
     );
   });
 
@@ -930,10 +930,10 @@ describe('GrepTool', () => {
     );
     expect(toolContentString(result)).toBe(
       [
-        'src\\main.ts:before',
-        'src\\main.ts:hit',
-        'src\\main.ts:after',
-        'Filtered 1 sensitive file(s): .aws\\credentials',
+        'src/main.ts:before',
+        'src/main.ts:hit',
+        'src/main.ts:after',
+        'Filtered 1 sensitive file(s): .aws/credentials',
       ].join('\n'),
     );
   });
@@ -1744,8 +1744,8 @@ describe('GrepTool', () => {
     const result = await executeTool(tool, context({ pattern: 'code', output_mode: 'content' }));
 
     const lines = toolContentString(result).split('\n');
-    expect(lines[0]).toBe('src\\a.py:42:code');
-    expect(lines[1]).toBe('src\\b.py-41-context');
+    expect(lines[0]).toBe('src/a.py:42:code');
+    expect(lines[1]).toBe('src/b.py-41-context');
   });
 
   it('passes lines through unchanged when path is not under the workspace', async () => {
diff --git a/packages/agent-core/test/tools/list-directory.test.ts b/packages/agent-core/test/tools/list-directory.test.ts
index f86de5d4..0b84b7ff 100644
--- a/packages/agent-core/test/tools/list-directory.test.ts
+++ b/packages/agent-core/test/tools/list-directory.test.ts
@@ -47,14 +47,15 @@ describe('listDirectory', () => {
       pathClass: () => 'win32',
       iterdir: async function* (p: string) {
         seenDirs.push(p);
-        if (p === 'C:\\workspace') {
+        const n = p.replaceAll('\\', '/');
+        if (n === 'C:/workspace') {
           yield 'C:\\workspace\\src';
-        } else if (p === 'C:\\workspace\\src') {
+        } else if (n === 'C:/workspace/src') {
           yield 'C:\\workspace\\src\\index.ts';
         }
       } as unknown as Kaos['iterdir'],
       stat: (async (p: string) => ({
-        stMode: p.endsWith('\\src') ? 0o040_755 : 0o100_644,
+        stMode: p.replaceAll('\\', '/').endsWith('/src') ? 0o040_755 : 0o100_644,
         stIno: 1,
         stDev: 1,
         stNlink: 1,
@@ -69,7 +70,7 @@ describe('listDirectory', () => {
 
     const tree = await listDirectory(kaos, 'C:\\workspace');
 
-    expect(seenDirs).toEqual(['C:\\workspace', 'C:\\workspace\\src']);
+    expect(seenDirs).toEqual(['C:\\workspace', 'C:/workspace/src']);
     expect(tree).toContain('src/');
     expect(tree).toContain('index.ts');
   });
diff --git a/packages/agent-core/test/tools/path-guard.test.ts b/packages/agent-core/test/tools/path-guard.test.ts
index 75c54eda..f3801fc8 100644
--- a/packages/agent-core/test/tools/path-guard.test.ts
+++ b/packages/agent-core/test/tools/path-guard.test.ts
@@ -168,8 +168,8 @@ describe('path access policy', () => {
       policy: DEFAULT_WORKSPACE_ACCESS_POLICY,
     });
 
-    expect(result).toEqual({ path: 'C:\\workspace\\file.txt', outsideWorkspace: false });
-    expect(isWithinDirectory('C:\\WORKSPACE\\file.txt', 'c:\\workspace', 'win32')).toBe(true);
+    expect(result).toEqual({ path: 'C:/workspace/file.txt', outsideWorkspace: false });
+    expect(isWithinDirectory('C:/WORKSPACE/file.txt', 'c:/workspace', 'win32')).toBe(true);
   });
 
   it('converts Git Bash POSIX drive paths before applying win32 workspace checks', () => {
@@ -180,7 +180,7 @@ describe('path access policy', () => {
       homeDir: 'C:\\Users\\test',
     });
 
-    expect(result).toEqual({ path: 'C:\\workspace\\file.txt', outsideWorkspace: false });
+    expect(result).toEqual({ path: 'C:/workspace/file.txt', outsideWorkspace: false });
   });
 
   it('uses the provided path class when deciding whether an outside path is absolute', () => {
@@ -190,7 +190,7 @@ describe('path access policy', () => {
       policy: DEFAULT_WORKSPACE_ACCESS_POLICY,
     });
 
-    expect(result).toEqual({ path: 'C:\\outside\\file.txt', outsideWorkspace: true });
+    expect(result).toEqual({ path: 'C:/outside/file.txt', outsideWorkspace: true });
   });
 
   it('expands leading tilde paths with the provided win32 home directory', () => {
@@ -202,7 +202,7 @@ describe('path access policy', () => {
     });
 
     expect(result).toEqual({
-      path: 'C:\\Users\\test\\notes\\today.txt',
+      path: 'C:/Users/test/notes/today.txt',
       outsideWorkspace: true,
     });
   });
@@ -313,26 +313,26 @@ describe('path access policy', () => {
 
   describe('normalizeUserPath on win32', () => {
     it('rewrites MSYS-style drive paths to native form', () => {
-      expect(normalizeUserPath('/c/Users/foo/file.txt', 'win32')).toBe('C:\\Users\\foo\\file.txt');
+      expect(normalizeUserPath('/c/Users/foo/file.txt', 'win32')).toBe('C:/Users/foo/file.txt');
     });
 
     it('rewrites a bare MSYS drive root to native form', () => {
-      expect(normalizeUserPath('/c/', 'win32')).toBe('C:\\');
-      expect(normalizeUserPath('/c', 'win32')).toBe('C:\\');
+      expect(normalizeUserPath('/c/', 'win32')).toBe('C:/');
+      expect(normalizeUserPath('/c', 'win32')).toBe('C:/');
     });
 
     it('canonicalizes the drive letter to uppercase', () => {
-      expect(normalizeUserPath('/C/Users/foo', 'win32')).toBe('C:\\Users\\foo');
+      expect(normalizeUserPath('/C/Users/foo', 'win32')).toBe('C:/Users/foo');
     });
 
     it('rewrites cygdrive-style paths to native form', () => {
-      expect(normalizeUserPath('/cygdrive/c/Users/foo', 'win32')).toBe('C:\\Users\\foo');
-      expect(normalizeUserPath('/cygdrive/d/Projects', 'win32')).toBe('D:\\Projects');
+      expect(normalizeUserPath('/cygdrive/c/Users/foo', 'win32')).toBe('C:/Users/foo');
+      expect(normalizeUserPath('/cygdrive/d/Projects', 'win32')).toBe('D:/Projects');
     });
 
-    it('rewrites UNC paths by flipping every slash', () => {
-      expect(normalizeUserPath('//server/share/file', 'win32')).toBe('\\\\server\\share\\file');
-      expect(normalizeUserPath('//server/share', 'win32')).toBe('\\\\server\\share');
+    it('rewrites UNC paths to forward slashes', () => {
+      expect(normalizeUserPath('//server/share/file', 'win32')).toBe('//server/share/file');
+      expect(normalizeUserPath('//server/share', 'win32')).toBe('//server/share');
     });
 
     it('leaves already-native windows paths untouched', () => {
@@ -365,15 +365,15 @@ describe('path access policy', () => {
 
   describe('normalizeUserPath full posix-to-windows coverage', () => {
     const cases: ReadonlyArray<readonly [string, string]> = [
-      ['/c/Users/foo', 'C:\\Users\\foo'],
-      ['/d/Projects/kimi', 'D:\\Projects\\kimi'],
-      ['/C/Users/foo', 'C:\\Users\\foo'],
-      ['/c/', 'C:\\'],
-      ['/c', 'C:\\'],
-      ['/cygdrive/c/Users/foo', 'C:\\Users\\foo'],
-      ['/cygdrive/d/Projects', 'D:\\Projects'],
-      ['//server/share', '\\\\server\\share'],
-      ['//server/share/file.txt', '\\\\server\\share\\file.txt'],
+      ['/c/Users/foo', 'C:/Users/foo'],
+      ['/d/Projects/kimi', 'D:/Projects/kimi'],
+      ['/C/Users/foo', 'C:/Users/foo'],
+      ['/c/', 'C:/'],
+      ['/c', 'C:/'],
+      ['/cygdrive/c/Users/foo', 'C:/Users/foo'],
+      ['/cygdrive/d/Projects', 'D:/Projects'],
+      ['//server/share', '//server/share'],
+      ['//server/share/file.txt', '//server/share/file.txt'],
       ['relative/path/file.txt', 'relative/path/file.txt'],
       ['relative\\already\\windows', 'relative\\already\\windows'],
       ['filename.txt', 'filename.txt'],
@@ -388,10 +388,10 @@ describe('path access policy', () => {
 
   it('aggressively rewrites short-input forms on win32', () => {
     // Pathological short inputs: empty, lone slash, and a single character.
-    // Treated as a divergence lockdown — the bare "/" branch differs from
-    // the upstream raw helper which flips the slash.
+    // The bare "/" branch returns a forward slash so downstream pathe
+    // operations stay uniform.
     expect(normalizeUserPath('', 'win32')).toBe('');
-    expect(normalizeUserPath('/', 'win32')).toBe('\\');
+    expect(normalizeUserPath('/', 'win32')).toBe('/');
     expect(normalizeUserPath('a', 'win32')).toBe('a');
   });
 
diff --git a/packages/agent-core/test/tools/rg-locator.test.ts b/packages/agent-core/test/tools/rg-locator.test.ts
index b0aaee15..badd6794 100644
--- a/packages/agent-core/test/tools/rg-locator.test.ts
+++ b/packages/agent-core/test/tools/rg-locator.test.ts
@@ -12,7 +12,7 @@ import { createHash } from 'node:crypto';
 import { existsSync, mkdirSync, readFileSync, rmSync, writeFileSync, chmodSync } from 'node:fs';
 import type * as FsPromises from 'node:fs/promises';
 import { tmpdir } from 'node:os';
-import { join } from 'node:path';
+import { join } from 'pathe';
 
 import { extract as extractTar } from 'tar';
 import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest';
diff --git a/packages/kaos/package.json b/packages/kaos/package.json
index 93418138..9da433b1 100644
--- a/packages/kaos/package.json
+++ b/packages/kaos/package.json
@@ -48,6 +48,7 @@
     "clean": "rm -rf dist"
   },
   "dependencies": {
+    "pathe": "^2.0.3",
     "ssh2": "^1.17.0"
   },
   "devDependencies": {
diff --git a/packages/kaos/src/local.ts b/packages/kaos/src/local.ts
index 71fa16b5..dd1146c4 100644
--- a/packages/kaos/src/local.ts
+++ b/packages/kaos/src/local.ts
@@ -11,7 +11,7 @@ import {
   writeFile,
 } from 'node:fs/promises';
 import { homedir } from 'node:os';
-import { isAbsolute, join as pathJoin, normalize } from 'node:path';
+import { isAbsolute, join, normalize } from 'pathe';
 import type { Readable, Writable } from 'node:stream';
 
 import { KaosFileExistsError } from './errors';
@@ -152,12 +152,12 @@ export class LocalKaos implements Kaos {
     // Snapshot the process cwd at construction time. After this point we
     // never touch process.cwd() / process.chdir() — all path resolution
     // goes through this._cwd.
-    this._cwd = process.cwd();
+    this._cwd = normalize(process.cwd());
   }
 
   private _resolvePath(path: string): string {
-    if (isAbsolute(path)) return path;
-    return pathJoin(this._cwd, path);
+    if (isAbsolute(path)) return normalize(path);
+    return join(this._cwd, path);
   }
 
   pathClass(): 'posix' | 'win32' {
@@ -169,7 +169,7 @@ export class LocalKaos implements Kaos {
   }
 
   gethome(): string {
-    return homedir();
+    return normalize(homedir());
   }
 
   getcwd(): string {
@@ -216,9 +216,9 @@ export class LocalKaos implements Kaos {
     const resolved = this._resolvePath(path);
     const entries = await readdir(resolved);
     for (const entry of entries) {
-      // Use pathJoin so root paths like "/" or "C:\\" don't produce "//entry"
-      // or "C:\\\\entry" — pathJoin normalizes trailing separators correctly.
-      yield pathJoin(resolved, entry);
+      // Use join so root paths like "/" or "C:\\" don't produce "//entry"
+      // or "C:\\\\entry" — join normalizes trailing separators correctly.
+      yield join(resolved, entry);
     }
   }
 
@@ -310,8 +310,8 @@ export class LocalKaos implements Kaos {
       }
 
       for (const entry of entries) {
-        // Use pathJoin to avoid "//entry" when basePath is a filesystem root.
-        const fullPath = pathJoin(basePath, entry);
+        // Use join to avoid "//entry" when basePath is a filesystem root.
+        const fullPath = join(basePath, entry);
         let entryStat;
         try {
           entryStat = await stat(fullPath);
@@ -348,8 +348,8 @@ export class LocalKaos implements Kaos {
           continue;
         }
 
-        // Use pathJoin to avoid "//entry" when basePath is a filesystem root.
-        const fullPath = pathJoin(basePath, entry);
+        // Use join to avoid "//entry" when basePath is a filesystem root.
+        const fullPath = join(basePath, entry);
 
         if (remainingParts.length === 0) {
           yield fullPath;
diff --git a/packages/kaos/src/path.ts b/packages/kaos/src/path.ts
index 7c895d21..120bc49f 100644
--- a/packages/kaos/src/path.ts
+++ b/packages/kaos/src/path.ts
@@ -26,14 +26,15 @@ function splitPathLexically(pathMod: PathModule, path: string): { root: string;
   const tail = root.length > 0 ? path.slice(root.length) : path;
   return {
     root,
-    parts: tail.split(pathMod.sep).filter((part) => part.length > 0),
+    parts: tail.split('/').filter((part) => part.length > 0),
   };
 }
 
 function splitPosixPart(path: string): { root: string; parts: string[] } {
+  const normalized = path.replaceAll('\\', '/');
   const root =
-    path.startsWith('//') && !path.startsWith('///') ? '//' : path.startsWith('/') ? '/' : '';
-  const tail = root.length > 0 ? path.slice(root.length) : path;
+    normalized.startsWith('//') && !normalized.startsWith('///') ? '//' : normalized.startsWith('/') ? '/' : '';
+  const tail = root.length > 0 ? normalized.slice(root.length) : normalized;
   return {
     root,
     parts: tail.split('/').filter((part) => part.length > 0 && part !== '.'),
@@ -154,13 +155,14 @@ export class KaosPath {
     if (args.length === 0) {
       this._path = '.';
     } else {
-      this._path = joinPure(this._pathClass, args);
+      const raw = joinPure(this._pathClass, args);
+      this._path = this._pathClass === 'win32' ? raw.replaceAll('\\', '/') : raw;
     }
   }
 
   private static _from(path: string, pathClass: PathClass): KaosPath {
     const ret = new KaosPath();
-    ret._path = path;
+    ret._path = path.replaceAll('\\', '/');
     ret._pathClass = pathClass;
     return ret;
   }
@@ -266,7 +268,7 @@ export class KaosPath {
 
     const relParts = target.parts.slice(base.parts.length);
     return KaosPath._from(
-      relParts.length === 0 ? '.' : relParts.join(pathMod.sep),
+      relParts.length === 0 ? '.' : relParts.join('/'),
       this._pathClass,
     );
   }
@@ -306,6 +308,9 @@ export class KaosPath {
 
   /** Return the underlying path string for local filesystem use. */
   toLocalPath(): string {
+    if (this._pathClass === 'win32') {
+      return this._path.replaceAll('/', '\\');
+    }
     return this._path;
   }
 
diff --git a/packages/kaos/src/ssh.ts b/packages/kaos/src/ssh.ts
index 71a92cae..75c29317 100644
--- a/packages/kaos/src/ssh.ts
+++ b/packages/kaos/src/ssh.ts
@@ -1,5 +1,5 @@
 import { readFile } from 'node:fs/promises';
-import { posix } from 'node:path';
+import { isAbsolute, join, normalize, resolve } from 'pathe';
 import type { Readable, Writable } from 'node:stream';
 
 import * as ssh2 from 'ssh2';
@@ -438,8 +438,8 @@ export class SSHKaos implements Kaos {
   }
 
   private _resolvePath(path: string): string {
-    if (posix.isAbsolute(path)) return path;
-    return posix.join(this._cwd, path);
+    if (isAbsolute(path)) return path;
+    return join(this._cwd, path);
   }
 
   /**
@@ -515,7 +515,7 @@ export class SSHKaos implements Kaos {
   }
 
   normpath(path: string): string {
-    return posix.normalize(path);
+    return normalize(path);
   }
 
   gethome(): string {
@@ -530,10 +530,10 @@ export class SSHKaos implements Kaos {
 
   async chdir(path: string): Promise<void> {
     let target: string;
-    if (posix.isAbsolute(path)) {
+    if (isAbsolute(path)) {
       target = path;
     } else {
-      target = posix.resolve(this._cwd, path);
+      target = resolve(this._cwd, path);
     }
     // Resolve to the real path via SFTP
     const resolved = await sftpRealpath(this._sftp, target);
@@ -578,7 +578,7 @@ export class SSHKaos implements Kaos {
     const entries = await sftpReaddir(this._sftp, resolved);
     for (const entry of entries) {
       if (entry.filename === '.' || entry.filename === '..') continue;
-      yield posix.join(resolved, entry.filename);
+      yield join(resolved, entry.filename);
     }
   }
 
@@ -637,7 +637,7 @@ export class SSHKaos implements Kaos {
 
       for (const entry of entries) {
         if (entry.filename === '.' || entry.filename === '..') continue;
-        const fullPath = posix.join(basePath, entry.filename);
+        const fullPath = join(basePath, entry.filename);
         if (entry.attrs.isDirectory()) {
           yield* this._globWalk(fullPath, patternParts, caseSensitive);
         } else if (remainingParts.length === 0) {
@@ -659,7 +659,7 @@ export class SSHKaos implements Kaos {
         if (entry.filename === '.' || entry.filename === '..') continue;
         if (!regex.test(entry.filename)) continue;
 
-        const fullPath = posix.join(basePath, entry.filename);
+        const fullPath = join(basePath, entry.filename);
 
         if (remainingParts.length === 0) {
           yield fullPath;
@@ -764,7 +764,7 @@ export class SSHKaos implements Kaos {
     let current = path.startsWith('/') ? '/' : '';
     const lastIndex = parts.length - 1;
     for (const [i, part] of parts.entries()) {
-      current = current ? posix.join(current, part) : part;
+      current = current ? join(current, part) : part;
 
       const isFinal = i === lastIndex;
 
diff --git a/packages/kaos/test/local.test.ts b/packages/kaos/test/local.test.ts
index dd8b88b6..dbce023d 100644
--- a/packages/kaos/test/local.test.ts
+++ b/packages/kaos/test/local.test.ts
@@ -71,6 +71,18 @@ describe('LocalKaos', () => {
       await kaos.writeText(filePath, 'content');
       await expect(kaos.chdir(filePath)).rejects.toThrow(/Not a directory/);
     });
+
+    it('should accept backslashes as path separators', async () => {
+      const nested = join(tempDir, 'backslash-test');
+      await kaos.mkdir(nested);
+      const filePath = join(nested, 'file.txt');
+      await kaos.writeText(filePath, 'hello');
+
+      // Use backslashes — they should be treated as forward slashes.
+      const backslashPath = filePath.replaceAll('/', '\\');
+      const statResult = await kaos.stat(backslashPath);
+      expect(statResult.stSize).toBe(Buffer.byteLength('hello', 'utf-8'));
+    });
   });
 
   describe('iterdir path normalization', () => {
diff --git a/packages/kaos/test/path.test.ts b/packages/kaos/test/path.test.ts
index a290c36b..c4cd6409 100644
--- a/packages/kaos/test/path.test.ts
+++ b/packages/kaos/test/path.test.ts
@@ -82,6 +82,13 @@ describe('KaosPath', () => {
       expect(new KaosPath('/usr', '/etc').toString()).toBe('/etc');
     });
 
+    it('should accept backslashes as separators on posix', () => {
+      const p = new KaosPath('foo\\bar\\baz');
+      expect(p.toString()).toBe('foo/bar/baz');
+      expect(p.name).toBe('baz');
+      expect(p.parent.toString()).toBe('foo/bar');
+    });
+
     it('should preserve parent references until canonical()', () => {
       const p = new KaosPath('/usr').joinpath('../etc');
       expect(p.toString()).toBe('/usr/../etc');
@@ -216,15 +223,15 @@ describe('KaosPath', () => {
     });
 
     it('should use win32 separators when the current kaos reports win32', async () => {
-      // Build a minimal Kaos mock that claims win32 path semantics. Canonical
-      // must not hard-code POSIX separators — it should use win32's resolver
-      // so relative paths joined with the Windows cwd use backslashes.
+      // Build a minimal Kaos mock that claims win32 path semantics. All
+      // paths produced by KaosPath must use forward slashes, even when the
+      // underlying path class is win32.
       const winKaos: Kaos = {
         name: 'mock-win32',
         pathClass: () => 'win32',
-        normpath: (p: string) => win32Path.normalize(p),
-        gethome: () => 'C:\\Users\\test',
-        getcwd: () => 'C:\\work\\project',
+        normpath: (p: string) => win32Path.normalize(p).replaceAll('\\', '/'),
+        gethome: () => 'C:/Users/test',
+        getcwd: () => 'C:/work/project',
         chdir: async () => {},
         stat: async () => ({
           stMode: 0,
@@ -259,13 +266,12 @@ describe('KaosPath', () => {
       const innerToken = setCurrentKaos(winKaos);
       try {
         const rel = new KaosPath('foo\\bar').canonical();
-        // Resolved against 'C:\\work\\project' → 'C:\\work\\project\\foo\\bar'.
-        // Critically: NO forward slashes in the result.
-        expect(rel.toString()).toBe('C:\\work\\project\\foo\\bar');
-        expect(rel.toString().includes('/')).toBe(false);
+        // Resolved against 'C:/work/project' → 'C:/work/project/foo/bar'.
+        expect(rel.toString()).toBe('C:/work/project/foo/bar');
+        expect(rel.toString().includes('\\')).toBe(false);
 
         const abs = new KaosPath('C:\\foo\\..\\bar').canonical();
-        expect(abs.toString()).toBe('C:\\bar');
+        expect(abs.toString()).toBe('C:/bar');
 
         expect(() => new KaosPath('D:\\logs').relativeTo(new KaosPath('C:\\work'))).toThrow(
           /not within/,
@@ -274,10 +280,10 @@ describe('KaosPath', () => {
           new KaosPath('C:\\Work\\Project').relativeTo(new KaosPath('c:\\work')).toString(),
         ).toBe('Project');
 
-        expect(new KaosPath('C:\\base').joinpath('D:\\logs').toString()).toBe('D:\\logs');
-        expect(new KaosPath('C:\\base').joinpath('\\rooted').toString()).toBe('C:\\rooted');
+        expect(new KaosPath('C:\\base').joinpath('D:\\logs').toString()).toBe('D:/logs');
+        expect(new KaosPath('C:\\base').joinpath('\\rooted').toString()).toBe('C:/rooted');
         expect(new KaosPath('C:\\base').joinpath('C:relative').toString()).toBe(
-          'C:\\base\\relative',
+          'C:/base/relative',
         );
         expect(new KaosPath('C:\\base').joinpath('D:relative').toString()).toBe('D:relative');
         expect(() => new KaosPath('D:relative').canonical()).toThrow(/drive-relative/);
@@ -428,6 +434,17 @@ describe('KaosPath', () => {
       expect(p.toLocalPath()).toBe(original);
       expect(p.toString()).toBe(original);
     });
+
+    it('should return backslashes for win32 toLocalPath', () => {
+      const innerToken = setCurrentKaos(makeMockKaos('win32'));
+      try {
+        const p = new KaosPath('C:/Users/test/file.txt');
+        expect(p.toLocalPath()).toBe('C:\\Users\\test\\file.txt');
+        expect(p.toString()).toBe('C:/Users/test/file.txt');
+      } finally {
+        resetCurrentKaos(innerToken);
+      }
+    });
   });
 
   describe('equals', () => {
@@ -460,7 +477,10 @@ describe('KaosPath', () => {
       const innerToken = setCurrentKaos(makeMockKaos('win32'));
       try {
         const winPath = new KaosPath('C:\\workspace');
-        expect(posixPath.toString()).toBe(winPath.toString());
+        // Both path classes normalise backslashes to forward slashes;
+        // they differ only in pathClass, so equals is still false.
+        expect(posixPath.toString()).toBe('C:/workspace');
+        expect(winPath.toString()).toBe('C:/workspace');
         expect(posixPath.equals(winPath)).toBe(false);
       } finally {
         resetCurrentKaos(innerToken);
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index c23aa42f..2cf82249 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -222,6 +222,9 @@ importers:
       open:
         specifier: ^10.2.0
         version: 10.2.0
+      pathe:
+        specifier: ^2.0.3
+        version: 2.0.3
       picomatch:
         specifier: ^4.0.4
         version: 4.0.4
@@ -280,6 +283,9 @@ importers:
 
   packages/kaos:
     dependencies:
+      pathe:
+        specifier: ^2.0.3
+        version: 2.0.3
       ssh2:
         specifier: ^1.17.0
         version: 1.17.0