diff --git a/scripts/electron-builder/afterPack.cjs b/scripts/electron-builder/afterPack.cjs
index c4ca053c..3ddcff23 100644
--- a/scripts/electron-builder/afterPack.cjs
+++ b/scripts/electron-builder/afterPack.cjs
@@ -159,6 +159,93 @@ async function pruneNodePtyArtifacts(appOutDir, platform, archLabel) {
   return removedPaths;
 }
 
+function findNodeModulesSequence(segments, sequence) {
+  for (let index = 0; index <= segments.length - sequence.length; index += 1) {
+    let matches = true;
+    for (let offset = 0; offset < sequence.length; offset += 1) {
+      if (segments[index + offset] !== sequence[offset]) {
+        matches = false;
+        break;
+      }
+    }
+    if (matches) {
+      return index;
+    }
+  }
+  return -1;
+}
+
+function getKnownPrunableNativeArtifactRoot(appOutDir, filePath, targetPlatform, targetArch) {
+  if (targetPlatform !== 'win32') {
+    return null;
+  }
+
+  const relativePath = path.relative(appOutDir, filePath);
+  const segments = relativePath.split(path.sep);
+
+  const conptyIndex = findNodeModulesSequence(segments, [
+    'node_modules',
+    'node-pty',
+    'third_party',
+    'conpty',
+  ]);
+  const conptyArchIndex = conptyIndex + 5;
+  const conptyArchDir = conptyIndex >= 0 ? segments[conptyArchIndex] : null;
+  if (conptyArchDir?.startsWith('win10-') && conptyArchDir !== `win10-${targetArch}`) {
+    return path.join(appOutDir, ...segments.slice(0, conptyArchIndex + 1));
+  }
+
+  return null;
+}
+
+function isKnownAllowedNativeMismatch(relativePath, format, archs, targetPlatform) {
+  const normalizedPath = relativePath.split(path.sep).join('/');
+  const ssh2PageantPath = 'node_modules/ssh2/util/pagent.exe';
+
+  return (
+    targetPlatform === 'win32' &&
+    (normalizedPath === ssh2PageantPath || normalizedPath.endsWith(`/${ssh2PageantPath}`)) &&
+    format === 'pe' &&
+    archs.size === 1 &&
+    archs.has('ia32')
+  );
+}
+
+async function pruneKnownIncompatibleNativeArtifacts(appOutDir, targetPlatform, targetArch) {
+  const files = await walkFiles(appOutDir);
+  const rootsToRemove = new Set();
+
+  for (const filePath of files) {
+    const rootToRemove = getKnownPrunableNativeArtifactRoot(
+      appOutDir,
+      filePath,
+      targetPlatform,
+      targetArch
+    );
+    if (!rootToRemove) {
+      continue;
+    }
+
+    const metadata = await detectBinaryMetadata(filePath);
+    if (!metadata) {
+      continue;
+    }
+
+    if (isBinaryCompatible(metadata.format, metadata.archs, targetPlatform, targetArch)) {
+      continue;
+    }
+
+    rootsToRemove.add(rootToRemove);
+  }
+
+  const removedPaths = [];
+  for (const absolutePath of rootsToRemove) {
+    await fs.promises.rm(absolutePath, { recursive: true, force: true });
+    removedPaths.push(absolutePath);
+  }
+  return removedPaths;
+}
+
 function mapMachOCpuType(cpuType) {
   switch (cpuType >>> 0) {
     case 0x00000007:
@@ -335,6 +422,7 @@ async function validateNativeBinaries(appOutDir, targetPlatform, targetArch) {
   const files = await walkFiles(appOutDir);
 
   for (const filePath of files) {
+    const relativePath = path.relative(appOutDir, filePath);
     const metadata = await detectBinaryMetadata(filePath);
     if (!metadata) {
       continue;
@@ -344,8 +432,14 @@ async function validateNativeBinaries(appOutDir, targetPlatform, targetArch) {
       continue;
     }
 
+    if (
+      isKnownAllowedNativeMismatch(relativePath, metadata.format, metadata.archs, targetPlatform)
+    ) {
+      continue;
+    }
+
     mismatches.push({
-      path: path.relative(appOutDir, filePath),
+      path: relativePath,
       format: metadata.format,
       archs: [...metadata.archs].sort(),
     });
@@ -358,7 +452,14 @@ async function afterPack(context) {
   const targetPlatform = context.electronPlatformName;
   const targetArch = getArchLabel(context.arch);
 
-  const removedPaths = await pruneNodePtyArtifacts(context.appOutDir, targetPlatform, targetArch);
+  const removedPaths = [
+    ...(await pruneNodePtyArtifacts(context.appOutDir, targetPlatform, targetArch)),
+    ...(await pruneKnownIncompatibleNativeArtifacts(
+      context.appOutDir,
+      targetPlatform,
+      targetArch
+    )),
+  ];
   const mismatches = await validateNativeBinaries(context.appOutDir, targetPlatform, targetArch);
 
   if (mismatches.length > 0) {
@@ -383,9 +484,11 @@ module.exports._internal = {
   detectBinaryMetadata,
   getArchLabel,
   isBinaryCompatible,
+  isKnownAllowedNativeMismatch,
   parseElf,
   parseMachO,
   parsePortableExecutable,
+  pruneKnownIncompatibleNativeArtifacts,
   pruneNodePtyArtifacts,
   validateNativeBinaries,
   walkFiles,
diff --git a/scripts/electron-builder/dist-invocations.cjs b/scripts/electron-builder/dist-invocations.cjs
new file mode 100644
index 00000000..a8f7db1c
--- /dev/null
+++ b/scripts/electron-builder/dist-invocations.cjs
@@ -0,0 +1,51 @@
+const PLATFORM_FLAGS = new Map([
+  ['--mac', 'mac'],
+  ['-m', 'mac'],
+  ['--win', 'win'],
+  ['-w', 'win'],
+  ['--linux', 'linux'],
+  ['-l', 'linux'],
+]);
+
+const PLATFORM_ARGS = {
+  mac: '--mac',
+  win: '--win',
+  linux: '--linux',
+};
+
+const LINUX_PACKAGE_NAME_OVERRIDES = [
+  '--config.productName=Agent-Teams-UI',
+  '--config.linux.desktop.entry.Name=Agent Teams UI',
+];
+
+function buildElectronBuilderInvocations(argv) {
+  const targets = [];
+  const sharedArgs = [];
+
+  for (const arg of argv) {
+    const target = PLATFORM_FLAGS.get(arg);
+    if (target) {
+      if (!targets.includes(target)) {
+        targets.push(target);
+      }
+      continue;
+    }
+    sharedArgs.push(arg);
+  }
+
+  if (targets.length === 0) {
+    return [{ args: sharedArgs }];
+  }
+
+  return targets.map((target) => ({
+    args: [
+      PLATFORM_ARGS[target],
+      ...sharedArgs,
+      ...(target === 'linux' ? LINUX_PACKAGE_NAME_OVERRIDES : []),
+    ],
+  }));
+}
+
+module.exports = {
+  buildElectronBuilderInvocations,
+};
diff --git a/scripts/electron-builder/dist.mjs b/scripts/electron-builder/dist.mjs
index e3c72615..cc98ed61 100644
--- a/scripts/electron-builder/dist.mjs
+++ b/scripts/electron-builder/dist.mjs
@@ -4,54 +4,9 @@ import { createRequire } from 'node:module';
 import { pathToFileURL } from 'node:url';
 
 const require = createRequire(import.meta.url);
+const { buildElectronBuilderInvocations } = require('./dist-invocations.cjs');
 
-const PLATFORM_FLAGS = new Map([
-  ['--mac', 'mac'],
-  ['-m', 'mac'],
-  ['--win', 'win'],
-  ['-w', 'win'],
-  ['--linux', 'linux'],
-  ['-l', 'linux'],
-]);
-
-const PLATFORM_ARGS = {
-  mac: '--mac',
-  win: '--win',
-  linux: '--linux',
-};
-
-const LINUX_PACKAGE_NAME_OVERRIDES = [
-  '--config.productName=Agent-Teams-UI',
-  '--config.linux.desktop.entry.Name=Agent Teams UI',
-];
-
-export function buildElectronBuilderInvocations(argv) {
-  const targets = [];
-  const sharedArgs = [];
-
-  for (const arg of argv) {
-    const target = PLATFORM_FLAGS.get(arg);
-    if (target) {
-      if (!targets.includes(target)) {
-        targets.push(target);
-      }
-      continue;
-    }
-    sharedArgs.push(arg);
-  }
-
-  if (targets.length === 0) {
-    return [{ args: sharedArgs }];
-  }
-
-  return targets.map((target) => ({
-    args: [
-      PLATFORM_ARGS[target],
-      ...sharedArgs,
-      ...(target === 'linux' ? LINUX_PACKAGE_NAME_OVERRIDES : []),
-    ],
-  }));
-}
+export { buildElectronBuilderInvocations };
 
 async function runElectronBuilder(args) {
   const cliPath = require.resolve('electron-builder/cli.js');
diff --git a/scripts/electron-builder/smokePackagedApp.cjs b/scripts/electron-builder/smokePackagedApp.cjs
index 68594830..9892a072 100644
--- a/scripts/electron-builder/smokePackagedApp.cjs
+++ b/scripts/electron-builder/smokePackagedApp.cjs
@@ -5,6 +5,7 @@ const { spawn } = require('node:child_process');
 
 const STARTUP_TIMEOUT_MS = Number(process.env.PACKAGED_SMOKE_TIMEOUT_MS ?? 30_000);
 const POST_STARTUP_STABLE_MS = Number(process.env.PACKAGED_SMOKE_STABLE_MS ?? 8_000);
+const SHUTDOWN_TIMEOUT_MS = Number(process.env.PACKAGED_SMOKE_SHUTDOWN_TIMEOUT_MS ?? 5_000);
 const REQUIRED_LOG_MARKERS = ['renderer did-finish-load'];
 const FAILURE_PATTERNS = [
   /Cannot find module/i,
@@ -39,7 +40,10 @@ function findExecutable(bundlePath, platform) {
   if (platform === 'win32') {
     const executable = fs
       .readdirSync(bundlePath)
-      .find((entry) => entry.toLowerCase().endsWith('.exe') && !entry.toLowerCase().includes('uninstall'));
+      .find(
+        (entry) =>
+          entry.toLowerCase().endsWith('.exe') && !entry.toLowerCase().includes('uninstall')
+      );
     if (!executable) fail(`No .exe found in ${bundlePath}`);
     return path.join(bundlePath, executable);
   }
@@ -66,6 +70,45 @@ function findExecutable(bundlePath, platform) {
   fail(`Unsupported platform: ${platform}`);
 }
 
+function waitForProcessClose(child, exitPromise, timeoutMs) {
+  if (child.exitCode !== null || child.signalCode !== null) {
+    return Promise.resolve(true);
+  }
+
+  let timeoutId;
+  const timeoutPromise = new Promise((resolve) => {
+    timeoutId = setTimeout(() => resolve(false), timeoutMs);
+  });
+  return Promise.race([exitPromise.then(() => true), timeoutPromise]).finally(() => {
+    if (timeoutId) {
+      clearTimeout(timeoutId);
+    }
+  });
+}
+
+async function terminateChild(child, exitPromise, platform) {
+  if (child.exitCode !== null || child.signalCode !== null) {
+    return;
+  }
+
+  if (platform === 'win32' && child.pid) {
+    await new Promise((resolve) => {
+      const killer = spawn('taskkill.exe', ['/pid', String(child.pid), '/T', '/F'], {
+        stdio: 'ignore',
+      });
+      killer.once('error', resolve);
+      killer.once('close', resolve);
+    });
+  } else {
+    child.kill();
+  }
+
+  const closed = await waitForProcessClose(child, exitPromise, SHUTDOWN_TIMEOUT_MS);
+  if (!closed && child.exitCode === null && child.signalCode === null) {
+    throw new Error(`Timed out after ${SHUTDOWN_TIMEOUT_MS}ms waiting for packaged app to exit`);
+  }
+}
+
 async function main() {
   const [bundlePathArg, platform] = process.argv.slice(2);
   if (!bundlePathArg || !platform) {
@@ -100,7 +143,7 @@ async function main() {
   let startupSeenAt = null;
   while (Date.now() < deadline) {
     if (FAILURE_PATTERNS.some((pattern) => pattern.test(log))) {
-      child.kill();
+      await terminateChild(child, exitPromise, platform);
       fail('Detected startup failure pattern', log);
     }
 
@@ -109,7 +152,7 @@ async function main() {
     }
 
     if (startupSeenAt !== null && Date.now() - startupSeenAt >= POST_STARTUP_STABLE_MS) {
-      child.kill();
+      await terminateChild(child, exitPromise, platform);
       console.log(`[smokePackagedApp] OK ${platform}: ${bundlePath}`);
       return;
     }
@@ -119,11 +162,14 @@ async function main() {
       new Promise((resolve) => setTimeout(() => resolve(null), 250)),
     ]);
     if (exit) {
-      fail(`Packaged app exited before startup completed: code=${exit.code} signal=${exit.signal}`, log);
+      fail(
+        `Packaged app exited before startup completed: code=${exit.code} signal=${exit.signal}`,
+        log
+      );
     }
   }
 
-  child.kill();
+  await terminateChild(child, exitPromise, platform);
   fail(`Timed out after ${STARTUP_TIMEOUT_MS}ms waiting for packaged startup`, log);
 }
 
diff --git a/scripts/electron-builder/verifyBundle.cjs b/scripts/electron-builder/verifyBundle.cjs
index 29ec81db..c4e68520 100644
--- a/scripts/electron-builder/verifyBundle.cjs
+++ b/scripts/electron-builder/verifyBundle.cjs
@@ -4,6 +4,18 @@ const afterPackModule = require('./afterPack.cjs');
 
 const { validateNativeBinaries } = afterPackModule._internal;
 
+function isAllowedPostPackMismatch(mismatch, platform, arch) {
+  const relativePath = mismatch.path.split(path.sep).join('/');
+  return (
+    platform === 'win32' &&
+    arch === 'x64' &&
+    relativePath === 'resources/elevate.exe' &&
+    mismatch.format === 'pe' &&
+    mismatch.archs.length === 1 &&
+    mismatch.archs[0] === 'ia32'
+  );
+}
+
 async function main() {
   const [bundlePathArg, platform, arch] = process.argv.slice(2);
 
@@ -14,16 +26,22 @@ async function main() {
 
   const bundlePath = path.resolve(bundlePathArg);
   const mismatches = await validateNativeBinaries(bundlePath, platform, arch);
+  const blockingMismatches = mismatches.filter(
+    (mismatch) => !isAllowedPostPackMismatch(mismatch, platform, arch)
+  );
 
-  if (mismatches.length === 0) {
-    console.log(`[verifyBundle] OK ${platform}-${arch}: ${bundlePath}`);
+  if (blockingMismatches.length === 0) {
+    const allowedCount = mismatches.length - blockingMismatches.length;
+    const suffix =
+      allowedCount > 0 ? ` (${allowedCount} allowed post-pack helper mismatch ignored)` : '';
+    console.log(`[verifyBundle] OK ${platform}-${arch}: ${bundlePath}${suffix}`);
     return;
   }
 
   console.error(
-    `[verifyBundle] Found ${mismatches.length} incompatible native binaries in ${platform}-${arch}: ${bundlePath}`
+    `[verifyBundle] Found ${blockingMismatches.length} incompatible native binaries in ${platform}-${arch}: ${bundlePath}`
   );
-  for (const mismatch of mismatches.slice(0, 50)) {
+  for (const mismatch of blockingMismatches.slice(0, 50)) {
     console.error(`- ${mismatch.path} [${mismatch.format}] -> ${mismatch.archs.join(', ')}`);
   }
   process.exit(1);
diff --git a/scripts/smoke/agent-attachments-smoke.mjs b/scripts/smoke/agent-attachments-smoke.mjs
index dc83b686..13f323d2 100644
--- a/scripts/smoke/agent-attachments-smoke.mjs
+++ b/scripts/smoke/agent-attachments-smoke.mjs
@@ -1,5 +1,6 @@
 #!/usr/bin/env node
-import { spawn } from 'node:child_process';
+import { spawn, spawnSync } from 'node:child_process';
+import { existsSync } from 'node:fs';
 import { mkdir, mkdtemp, readFile, writeFile } from 'node:fs/promises';
 import { tmpdir } from 'node:os';
 import path from 'node:path';
@@ -326,12 +327,93 @@ function parseArgs(argv) {
   return { all, jsonPath, list, selected };
 }
 
+function hasPathSeparator(value) {
+  return value.includes('/') || value.includes('\\');
+}
+
+function resolveWindowsSpawnBinary(binary) {
+  if (process.platform !== 'win32') {
+    return binary;
+  }
+
+  if (hasPathSeparator(binary)) {
+    if (!path.extname(binary) && existsSync(`${binary}.cmd`)) {
+      return `${binary}.cmd`;
+    }
+    return binary;
+  }
+
+  const whereResult = spawnSync('where.exe', [binary], {
+    encoding: 'utf8',
+    windowsHide: true,
+  });
+  if (whereResult.status !== 0 || !whereResult.stdout) {
+    return binary;
+  }
+
+  const candidates = whereResult.stdout
+    .split(/\r?\n/)
+    .map((candidate) => candidate.trim())
+    .filter(Boolean);
+  const extensionlessShim = candidates.find(
+    (candidate) => !path.extname(candidate) && existsSync(`${candidate}.cmd`)
+  );
+  if (extensionlessShim) {
+    return `${extensionlessShim}.cmd`;
+  }
+  return (
+    candidates.find((candidate) => /\.exe$/i.test(candidate)) ??
+    candidates.find((candidate) => /\.(?:cmd|bat)$/i.test(candidate)) ??
+    candidates[0] ??
+    binary
+  );
+}
+
+function quoteWindowsCmdArg(value) {
+  const text = String(value);
+  if (text.length === 0) {
+    return '""';
+  }
+  if (!/[ \t\r\n"&|<>^()%!]/.test(text)) {
+    return text;
+  }
+  return `"${text.replace(/%/g, '%%').replace(/(["^&|<>])/g, '^$1')}"`;
+}
+
+function buildSpawnInvocation(command) {
+  if (process.platform !== 'win32') {
+    return {
+      bin: command.bin,
+      args: command.args,
+      options: { windowsHide: true },
+    };
+  }
+
+  const resolvedBin = resolveWindowsSpawnBinary(command.bin);
+  if (/\.(?:cmd|bat)$/i.test(resolvedBin)) {
+    const commandLine = [resolvedBin, ...command.args].map(quoteWindowsCmdArg).join(' ');
+    return {
+      bin: process.env.ComSpec || 'cmd.exe',
+      args: ['/d', '/s', '/c', commandLine],
+      options: { windowsHide: true, windowsVerbatimArguments: true },
+    };
+  }
+
+  return {
+    bin: resolvedBin,
+    args: command.args,
+    options: { windowsHide: true },
+  };
+}
+
 function runCommand(command) {
   return new Promise((resolve) => {
-    const child = spawn(command.bin, command.args, {
+    const spawnInvocation = buildSpawnInvocation(command);
+    const child = spawn(spawnInvocation.bin, spawnInvocation.args, {
       stdio: ['pipe', 'pipe', 'pipe'],
       env: process.env,
       cwd: command.cwd,
+      ...spawnInvocation.options,
     });
     let stdout = '';
     let stderr = '';
diff --git a/src/features/recent-projects/renderer/utils/recentProjectOpenHistory.ts b/src/features/recent-projects/renderer/utils/recentProjectOpenHistory.ts
index 28d8b880..0b3be39c 100644
--- a/src/features/recent-projects/renderer/utils/recentProjectOpenHistory.ts
+++ b/src/features/recent-projects/renderer/utils/recentProjectOpenHistory.ts
@@ -1,4 +1,5 @@
 import { isEphemeralProjectPath } from '@shared/utils/ephemeralProjectPath';
+import { normalizePathForComparison } from '@shared/utils/platformPath';
 
 import type { DashboardRecentProject } from '@features/recent-projects/contracts';
 
@@ -34,7 +35,7 @@ function normalizeHistoryPath(projectPath: string): string | null {
       normalizedPath = normalizedPath.slice(0, -1);
     }
   }
-  return normalizedPath;
+  return normalizedPath ? normalizePathForComparison(normalizedPath) : null;
 }
 
 function foldHistoryPath(projectPath: string): string {
diff --git a/src/main/services/editor/FileSearchService.ts b/src/main/services/editor/FileSearchService.ts
index 52ce0927..691f3603 100644
--- a/src/main/services/editor/FileSearchService.ts
+++ b/src/main/services/editor/FileSearchService.ts
@@ -292,9 +292,7 @@ export class FileSearchService {
         subdirs.push(fullPath);
       } else if (entry.isFile()) {
         if (IGNORED_FILES.has(entry.name)) continue;
-        const relativePath = fullPath.startsWith(projectRoot)
-          ? fullPath.slice(projectRoot.length + 1)
-          : entry.name;
+        const relativePath = path.relative(projectRoot, fullPath).split(path.sep).join('/');
         files.push({ path: fullPath, name: entry.name, relativePath });
       }
     }
diff --git a/src/renderer/components/chat/SessionContextPanel/DirectoryTree/buildDirectoryTree.ts b/src/renderer/components/chat/SessionContextPanel/DirectoryTree/buildDirectoryTree.ts
index 48e38d43..9bb7f723 100644
--- a/src/renderer/components/chat/SessionContextPanel/DirectoryTree/buildDirectoryTree.ts
+++ b/src/renderer/components/chat/SessionContextPanel/DirectoryTree/buildDirectoryTree.ts
@@ -2,6 +2,8 @@
  * Build a directory tree structure from CLAUDE.md injections.
  */
 
+import { getRelativePathWithinPrefix } from '@shared/utils/platformPath';
+
 import type { TreeNode } from './types';
 import type { ClaudeMdContextInjection } from '@renderer/types/contextInjection';
 
@@ -15,12 +17,9 @@ export function buildDirectoryTree(
   const root: TreeNode = { name: '', path: '', isFile: false, children: new Map() };
 
   for (const injection of injections) {
-    let relativePath = injection.path;
-    if (projectRoot && relativePath.startsWith(projectRoot)) {
-      relativePath = relativePath.slice(projectRoot.length);
-      if (relativePath.startsWith('/') || relativePath.startsWith('\\'))
-        relativePath = relativePath.slice(1);
-    }
+    const relativePath = projectRoot
+      ? getRelativePathWithinPrefix(projectRoot, injection.path) ?? injection.path
+      : injection.path;
 
     const parts = relativePath.split(/[\\/]/);
     let current = root;
diff --git a/src/renderer/components/chat/viewers/FileLink.tsx b/src/renderer/components/chat/viewers/FileLink.tsx
index 7ed49cf7..4b1017b8 100644
--- a/src/renderer/components/chat/viewers/FileLink.tsx
+++ b/src/renderer/components/chat/viewers/FileLink.tsx
@@ -57,21 +57,20 @@ export function resolveFileLinkPath(filePath: string, projectPath: string): stri
 function normalizePathSegments(filePath: string): string {
   const hasBackslash = filePath.includes('\\') && !filePath.includes('/');
   const separator = hasBackslash ? '\\' : '/';
-  const normalized = filePath.replace(/[/\\]+/g, separator);
 
   let prefix = '';
-  let body = normalized;
+  let body = filePath;
 
-  const driveMatch = /^([A-Za-z]:)[\\/]/.exec(normalized);
+  const driveMatch = /^([A-Za-z]:)[\\/]/.exec(filePath);
   if (driveMatch) {
     prefix = `${driveMatch[1]}${separator}`;
-    body = normalized.slice(prefix.length);
-  } else if (normalized.startsWith(`${separator}${separator}`)) {
+    body = filePath.slice(driveMatch[0].length);
+  } else if (filePath.startsWith('\\\\') || filePath.startsWith('//')) {
     prefix = `${separator}${separator}`;
-    body = normalized.slice(2);
-  } else if (normalized.startsWith(separator)) {
+    body = filePath.slice(2);
+  } else if (filePath.startsWith('/') || filePath.startsWith('\\')) {
     prefix = separator;
-    body = normalized.slice(1);
+    body = filePath.slice(1);
   }
 
   const segments: string[] = [];
diff --git a/src/renderer/components/chat/viewers/MarkdownViewer.tsx b/src/renderer/components/chat/viewers/MarkdownViewer.tsx
index 90faaf38..cca878d4 100644
--- a/src/renderer/components/chat/viewers/MarkdownViewer.tsx
+++ b/src/renderer/components/chat/viewers/MarkdownViewer.tsx
@@ -27,6 +27,7 @@ import {
 import { getTeamColorSet, getThemedBadge } from '@renderer/constants/teamColors';
 import { useTheme } from '@renderer/hooks/useTheme';
 import { useStore } from '@renderer/store';
+import { resolveFilePath } from '@renderer/store/utils/pathResolution';
 import { REHYPE_PLUGINS, REHYPE_PLUGINS_NO_HIGHLIGHT } from '@renderer/utils/markdownPlugins';
 import { nameColorSet } from '@renderer/utils/projectColor';
 import { parseTaskLinkHref } from '@renderer/utils/taskReferenceUtils';
@@ -318,9 +319,8 @@ function isAllowedElement(element: { tagName: string }): boolean {
 }
 
 /** Resolve a relative path to an absolute path given a base directory */
-function resolveRelativePath(relativeSrc: string, baseDir: string): string {
-  const cleaned = relativeSrc.startsWith('./') ? relativeSrc.slice(2) : relativeSrc;
-  return `${baseDir}/${cleaned}`;
+export function resolveRelativePath(relativeSrc: string, baseDir: string): string {
+  return resolveFilePath(baseDir, relativeSrc);
 }
 
 // =============================================================================
diff --git a/src/renderer/components/settings/sections/GeneralSection.tsx b/src/renderer/components/settings/sections/GeneralSection.tsx
index 0e653f52..dd0ef9a1 100644
--- a/src/renderer/components/settings/sections/GeneralSection.tsx
+++ b/src/renderer/components/settings/sections/GeneralSection.tsx
@@ -254,7 +254,9 @@ export const GeneralSection = ({
   const resolvedClaudeRootPath = claudeRootInfo?.resolvedPath ?? '~/.claude';
   const defaultClaudeRootPath = claudeRootInfo?.defaultPath ?? '~/.claude';
   const isWindowsStyleDefaultPath =
-    /^[a-zA-Z]:\\/.test(defaultClaudeRootPath) || defaultClaudeRootPath.startsWith('\\\\');
+    /^[a-zA-Z]:[/\\]/.test(defaultClaudeRootPath) ||
+    defaultClaudeRootPath.startsWith('\\\\') ||
+    defaultClaudeRootPath.startsWith('//');
 
   const isElectron = useMemo(() => isElectronMode(), []);
 
diff --git a/src/renderer/components/team/editor/EditorContextMenu.tsx b/src/renderer/components/team/editor/EditorContextMenu.tsx
index 5a795ff9..befabb3f 100644
--- a/src/renderer/components/team/editor/EditorContextMenu.tsx
+++ b/src/renderer/components/team/editor/EditorContextMenu.tsx
@@ -9,7 +9,7 @@
 import React, { useCallback, useRef, useState } from 'react';
 
 import * as ContextMenu from '@radix-ui/react-context-menu';
-import { lastSeparatorIndex } from '@shared/utils/platformPath';
+import { getRelativePathWithinPrefix, lastSeparatorIndex } from '@shared/utils/platformPath';
 import {
   ClipboardCopy,
   FilePlus,
@@ -87,6 +87,8 @@ export const EditorContextMenu = ({
       ? target.path
       : target.path.substring(0, lastSeparatorIndex(target.path))
     : null;
+  const targetRelativePath =
+    projectPath && target ? getRelativePathWithinPrefix(projectPath, target.path) : null;
 
   return (
     <ContextMenu.Root>
@@ -154,12 +156,11 @@ export const EditorContextMenu = ({
                 Copy Path
               </ContextMenu.Item>
 
-              {projectPath && target.path.startsWith(projectPath) && (
+              {targetRelativePath !== null && (
                 <ContextMenu.Item
                   className="flex cursor-pointer items-center gap-2 rounded px-2 py-1.5 text-xs text-text outline-none hover:bg-surface-raised focus:bg-surface-raised"
                   onSelect={() => {
-                    const relative = target.path.slice(projectPath.length + 1);
-                    void navigator.clipboard.writeText(relative);
+                    void navigator.clipboard.writeText(targetRelativePath);
                   }}
                 >
                   <ClipboardCopy className="size-3.5 text-text-muted" />
diff --git a/src/renderer/components/team/editor/SearchInFilesPanel.tsx b/src/renderer/components/team/editor/SearchInFilesPanel.tsx
index 4253a22d..81d57b58 100644
--- a/src/renderer/components/team/editor/SearchInFilesPanel.tsx
+++ b/src/renderer/components/team/editor/SearchInFilesPanel.tsx
@@ -10,7 +10,11 @@ import React, { useCallback, useEffect, useRef, useState } from 'react';
 import { api } from '@renderer/api';
 import { Button } from '@renderer/components/ui/button';
 import { Tooltip, TooltipContent, TooltipTrigger } from '@renderer/components/ui/tooltip';
-import { getBasename, lastSeparatorIndex } from '@shared/utils/platformPath';
+import {
+  getBasename,
+  getRelativePathWithinPrefix,
+  lastSeparatorIndex,
+} from '@shared/utils/platformPath';
 import { Loader2, Search, X } from 'lucide-react';
 
 import { FileIcon } from './FileIcon';
@@ -146,7 +150,7 @@ export const SearchInFilesPanel = ({
 
   const getRelativePath = useCallback(
     (filePath: string) => {
-      return filePath.startsWith(projectPath) ? filePath.slice(projectPath.length + 1) : filePath;
+      return getRelativePathWithinPrefix(projectPath, filePath) ?? filePath;
     },
     [projectPath]
   );
diff --git a/src/renderer/hooks/useFileSuggestions.ts b/src/renderer/hooks/useFileSuggestions.ts
index 15b8541e..f5a8449c 100644
--- a/src/renderer/hooks/useFileSuggestions.ts
+++ b/src/renderer/hooks/useFileSuggestions.ts
@@ -13,6 +13,7 @@ import {
   onQuickOpenCacheInvalidated,
   setQuickOpenCache,
 } from '@renderer/utils/quickOpenCache';
+import { joinPath, splitPath } from '@shared/utils/platformPath';
 
 import type { MentionSuggestion } from '@renderer/types/mention';
 import type { QuickOpenFile } from '@shared/types/editor';
@@ -53,12 +54,12 @@ export function formatFileMentionPath(relativePath: string): string {
  * Extracts unique directories from a list of file paths.
  * Returns directories sorted by depth (shallower first), then alphabetically.
  */
-function extractDirectories(files: QuickOpenFile[], projectPath: string): DerivedFolder[] {
+export function extractDirectories(files: QuickOpenFile[], projectPath: string): DerivedFolder[] {
   const dirSet = new Set<string>();
 
   for (const f of files) {
     // Walk up the directory chain from each file's relative path
-    const parts = f.relativePath.split('/');
+    const parts = splitPath(f.relativePath);
     // Remove the file name — keep only directory segments
     for (let i = 1; i < parts.length; i++) {
       dirSet.add(parts.slice(0, i).join('/'));
@@ -67,19 +68,19 @@ function extractDirectories(files: QuickOpenFile[], projectPath: string): Derive
 
   const folders: DerivedFolder[] = [];
   for (const relDir of dirSet) {
-    const segments = relDir.split('/');
+    const segments = splitPath(relDir);
     const name = segments[segments.length - 1];
     folders.push({
       name,
       relativePath: relDir + '/',
-      absolutePath: projectPath + '/' + relDir,
+      absolutePath: joinPath(projectPath, ...splitPath(relDir)),
     });
   }
 
   // Sort: shallower first, then alphabetically
   folders.sort((a, b) => {
-    const depthA = a.relativePath.split('/').length;
-    const depthB = b.relativePath.split('/').length;
+    const depthA = splitPath(a.relativePath).length;
+    const depthB = splitPath(b.relativePath).length;
     if (depthA !== depthB) return depthA - depthB;
     return a.relativePath.localeCompare(b.relativePath);
   });
@@ -94,13 +95,14 @@ function extractDirectories(files: QuickOpenFile[], projectPath: string): Derive
 export function filterFileSuggestions(files: QuickOpenFile[], query: string): MentionSuggestion[] {
   if (!query || files.length === 0) return [];
 
-  const lower = query.toLowerCase();
+  const lower = query.replace(/\\/g, '/').toLowerCase();
   const results: MentionSuggestion[] = [];
 
   for (const f of files) {
     if (results.length >= MAX_FILE_SUGGESTIONS) break;
 
-    if (f.name.toLowerCase().includes(lower) || f.relativePath.toLowerCase().includes(lower)) {
+    const relativePathForMatch = f.relativePath.replace(/\\/g, '/').toLowerCase();
+    if (f.name.toLowerCase().includes(lower) || relativePathForMatch.includes(lower)) {
       results.push({
         id: `file:${f.path}`,
         name: f.name,
@@ -127,14 +129,15 @@ export function filterFolderSuggestions(
   if (!query || folders.length === 0) return [];
 
   // Strip trailing slash from query for matching (e.g. "ui/" -> "ui")
-  const cleanQuery = query.endsWith('/') ? query.slice(0, -1) : query;
-  const lower = cleanQuery.toLowerCase();
+  const cleanQuery = query.endsWith('/') || query.endsWith('\\') ? query.slice(0, -1) : query;
+  const lower = cleanQuery.replace(/\\/g, '/').toLowerCase();
   const results: MentionSuggestion[] = [];
 
   for (const f of folders) {
     if (results.length >= MAX_FOLDER_SUGGESTIONS) break;
 
-    if (f.name.toLowerCase().includes(lower) || f.relativePath.toLowerCase().includes(lower)) {
+    const relativePathForMatch = f.relativePath.replace(/\\/g, '/').toLowerCase();
+    if (f.name.toLowerCase().includes(lower) || relativePathForMatch.includes(lower)) {
       results.push({
         id: `folder:${f.absolutePath}`,
         name: f.name + '/',
diff --git a/src/renderer/store/utils/pathResolution.ts b/src/renderer/store/utils/pathResolution.ts
index 7d520af8..43b58f0f 100644
--- a/src/renderer/store/utils/pathResolution.ts
+++ b/src/renderer/store/utils/pathResolution.ts
@@ -2,6 +2,8 @@
  * Path resolution utilities for the store.
  */
 
+import { stripTrailingSeparators } from '@shared/utils/platformPath';
+
 /**
  * Resolves a relative path against a base path, handling various path formats.
  * Handles:
@@ -17,7 +19,7 @@ export function resolveFilePath(base: string, relativePath: string): string {
     return relativePath;
   }
 
-  const cleanBase = trimTrailingSeparator(base);
+  const cleanBase = stripTrailingSeparators(base);
 
   // Handle @ prefix (file mention marker) - strip it if present
   let cleanRelative = relativePath;
@@ -32,21 +34,22 @@ export function resolveFilePath(base: string, relativePath: string): string {
   }
 
   // Handle ./ prefix (current directory)
-  if (cleanRelative.startsWith('./')) {
+  if (cleanRelative.startsWith('./') || cleanRelative.startsWith('.\\')) {
     cleanRelative = cleanRelative.slice(2);
   }
 
   // Handle ../ prefixes (parent directory)
   const separator = cleanBase.includes('\\') ? '\\' : '/';
-  const hasUnixRoot = cleanBase.startsWith('/');
-  const hasUncRoot = cleanBase.startsWith('\\\\');
+  const hasUncRoot = cleanBase.startsWith('\\\\') || cleanBase.startsWith('//');
+  const hasUnixRoot = !hasUncRoot && cleanBase.startsWith('/');
+  const minRootParts = hasUncRoot ? 2 : 1;
   const normalizedRelative = normalizeSeparators(cleanRelative, separator);
   const baseParts = splitPath(cleanBase);
   let remainingRelative = normalizedRelative;
 
   while (remainingRelative.startsWith(`..${separator}`)) {
     remainingRelative = remainingRelative.slice(3);
-    if (baseParts.length > 1) {
+    if (baseParts.length > minRootParts) {
       baseParts.pop();
     }
   }
@@ -56,8 +59,8 @@ export function resolveFilePath(base: string, relativePath: string): string {
   if (hasUnixRoot && !normalizedBase.startsWith('/')) {
     normalizedBase = `/${normalizedBase}`;
   }
-  if (hasUncRoot && !normalizedBase.startsWith('\\\\')) {
-    normalizedBase = `\\\\${normalizedBase}`;
+  if (hasUncRoot && !normalizedBase.startsWith(`${separator}${separator}`)) {
+    normalizedBase = `${separator}${separator}${normalizedBase}`;
   }
   return remainingRelative ? `${normalizedBase}${separator}${remainingRelative}` : normalizedBase;
 }
@@ -66,18 +69,6 @@ function isAbsolutePath(input: string): boolean {
   return input.startsWith('/') || input.startsWith('\\\\') || /^[a-zA-Z]:[\\/]/.test(input);
 }
 
-function trimTrailingSeparator(input: string): string {
-  let end = input.length;
-  while (end > 0) {
-    const char = input[end - 1];
-    if (char !== '/' && char !== '\\') {
-      break;
-    }
-    end--;
-  }
-  return input.slice(0, end);
-}
-
 function normalizeSeparators(input: string, separator: '/' | '\\'): string {
   let output = '';
   let prevWasSeparator = false;
diff --git a/src/renderer/utils/claudeMdTracker.ts b/src/renderer/utils/claudeMdTracker.ts
index 5510d570..ac045070 100644
--- a/src/renderer/utils/claudeMdTracker.ts
+++ b/src/renderer/utils/claudeMdTracker.ts
@@ -8,8 +8,11 @@
  */
 
 import {
+  isPathPrefix,
   lastSeparatorIndex,
+  normalizePathForComparison,
   splitPath as splitPathCrossPlatform,
+  stripTrailingSeparators,
 } from '@shared/utils/platformPath';
 
 import { extractFileReferences } from './groupTransformer';
@@ -64,7 +67,14 @@ export function getDisplayName(path: string, _source: ClaudeMdSource): string {
  * Check if a path is absolute (starts with /).
  */
 function isAbsolutePath(path: string): boolean {
-  return path.startsWith('/') || path.startsWith('\\\\') || /^[a-zA-Z]:[\\/]/.test(path);
+  return (
+    path.startsWith('/') ||
+    path.startsWith('~/') ||
+    path.startsWith('~\\') ||
+    path === '~' ||
+    path.startsWith('\\\\') ||
+    /^[a-zA-Z]:[\\/]/.test(path)
+  );
 }
 
 /**
@@ -82,7 +92,7 @@ function joinPaths(base: string, relative: string): string {
   }
 
   // Remove trailing slash from base if present
-  const cleanBase = trimTrailingSeparator(base);
+  const cleanBase = stripTrailingSeparators(base);
 
   // Handle @ prefix (file mention marker) - strip it if present
   let cleanRelative = relative;
@@ -91,20 +101,21 @@ function joinPaths(base: string, relative: string): string {
   }
 
   // Handle ./ prefix (current directory)
-  if (cleanRelative.startsWith('./')) {
+  if (cleanRelative.startsWith('./') || cleanRelative.startsWith('.\\')) {
     cleanRelative = cleanRelative.slice(2);
   }
 
   // Handle ../ prefixes (parent directory)
   const separator = cleanBase.includes('\\') ? '\\' : '/';
-  const hasUnixRoot = cleanBase.startsWith('/');
-  const hasUncRoot = cleanBase.startsWith('\\\\');
+  const hasUncRoot = cleanBase.startsWith('\\\\') || cleanBase.startsWith('//');
+  const hasUnixRoot = !hasUncRoot && cleanBase.startsWith('/');
+  const minRootParts = hasUncRoot ? 2 : 1;
   const normalizedRelative = normalizeSeparators(cleanRelative, separator);
   const baseParts = splitPath(cleanBase);
   let remainingRelative = normalizedRelative;
   while (remainingRelative.startsWith(`..${separator}`)) {
     remainingRelative = remainingRelative.slice(3);
-    if (baseParts.length > 1) {
+    if (baseParts.length > minRootParts) {
       baseParts.pop();
     }
   }
@@ -114,24 +125,12 @@ function joinPaths(base: string, relative: string): string {
   if (hasUnixRoot && !normalizedBase.startsWith('/')) {
     normalizedBase = `/${normalizedBase}`;
   }
-  if (hasUncRoot && !normalizedBase.startsWith('\\\\')) {
-    normalizedBase = `\\\\${normalizedBase}`;
+  if (hasUncRoot && !normalizedBase.startsWith(`${separator}${separator}`)) {
+    normalizedBase = `${separator}${separator}${normalizedBase}`;
   }
   return remainingRelative ? `${normalizedBase}${separator}${remainingRelative}` : normalizedBase;
 }
 
-function trimTrailingSeparator(input: string): string {
-  let end = input.length;
-  while (end > 0) {
-    const char = input[end - 1];
-    if (char !== '/' && char !== '\\') {
-      break;
-    }
-    end--;
-  }
-  return input.slice(0, end);
-}
-
 function normalizeSeparators(input: string, separator: '/' | '\\'): string {
   let output = '';
   let prevWasSeparator = false;
@@ -158,7 +157,19 @@ function splitPath(input: string): string[] {
 }
 
 function normalizeForComparison(input: string): string {
-  return input.replace(/\\/g, '/');
+  return normalizePathForComparison(input);
+}
+
+function createSeenPathSet(paths: string[]): Set<string> {
+  return new Set(paths.map(normalizeForComparison));
+}
+
+function hasSeenPath(seenPaths: Set<string>, path: string): boolean {
+  return seenPaths.has(normalizeForComparison(path));
+}
+
+function rememberPath(seenPaths: Set<string>, path: string): void {
+  seenPaths.add(normalizeForComparison(path));
 }
 
 /**
@@ -183,11 +194,7 @@ export function getParentDirectory(dirPath: string): string | null {
  * Check if dirPath is at or above stopPath in the directory tree.
  */
 function isAtOrAbove(dirPath: string, stopPath: string): boolean {
-  const normDir = normalizeForComparison(dirPath).replace(/\/$/, '');
-  const normStop = normalizeForComparison(stopPath).replace(/\/$/, '');
-
-  // dirPath is at or above stopPath if stopPath starts with dirPath
-  return normStop === normDir || normStop.startsWith(normDir + '/');
+  return isPathPrefix(dirPath, stopPath);
 }
 
 // =============================================================================
@@ -485,7 +492,7 @@ function computeClaudeMdStats(params: ComputeClaudeMdStatsParams): ClaudeMdStats
   } = params;
 
   const newInjections: ClaudeMdInjection[] = [];
-  const previousPaths = new Set(previousInjections.map((inj) => inj.path));
+  const previousPaths = createSeenPathSet(previousInjections.map((inj) => inj.path));
 
   // For the first group, add global injections
   // Use "ai-N" format for firstSeenInGroup to enable turn navigation in SessionClaudeMdPanel
@@ -493,9 +500,9 @@ function computeClaudeMdStats(params: ComputeClaudeMdStatsParams): ClaudeMdStats
   if (isFirstGroup) {
     const globalInjections = createGlobalInjections(projectRoot, turnGroupId, tokenData);
     for (const injection of globalInjections) {
-      if (!previousPaths.has(injection.path)) {
+      if (!hasSeenPath(previousPaths, injection.path)) {
         newInjections.push(injection);
-        previousPaths.add(injection.path);
+        rememberPath(previousPaths, injection.path);
       }
     }
   }
@@ -526,7 +533,7 @@ function computeClaudeMdStats(params: ComputeClaudeMdStatsParams): ClaudeMdStats
 
     for (const claudeMdPath of claudeMdPaths) {
       // Skip if already seen
-      if (previousPaths.has(claudeMdPath)) {
+      if (hasSeenPath(previousPaths, claudeMdPath)) {
         continue;
       }
 
@@ -546,7 +553,7 @@ function computeClaudeMdStats(params: ComputeClaudeMdStatsParams): ClaudeMdStats
       // Create directory injection
       const injection = createDirectoryInjection(claudeMdPath, turnGroupId);
       newInjections.push(injection);
-      previousPaths.add(claudeMdPath);
+      rememberPath(previousPaths, claudeMdPath);
     }
   }
 
diff --git a/src/renderer/utils/contextTracker.ts b/src/renderer/utils/contextTracker.ts
index 78eb4986..ec8ecd8e 100644
--- a/src/renderer/utils/contextTracker.ts
+++ b/src/renderer/utils/contextTracker.ts
@@ -9,6 +9,7 @@
  * This builds on claudeMdTracker.ts and extends it to track all context sources.
  */
 
+import { normalizePathForComparison, stripTrailingSeparators } from '@shared/utils/platformPath';
 import { estimateTokens } from '@shared/utils/tokenFormatting';
 
 import { MAX_MENTIONED_FILE_TOKENS } from '../types/contextInjection';
@@ -474,7 +475,7 @@ function joinPaths(base: string, relative: string): string {
     return relative;
   }
 
-  const cleanBase = trimTrailingSeparator(base);
+  const cleanBase = stripTrailingSeparators(base);
 
   // Handle @ prefix (file mention marker) - strip it if present
   let cleanRelative = relative;
@@ -483,20 +484,21 @@ function joinPaths(base: string, relative: string): string {
   }
 
   // Handle ./ prefix (current directory)
-  if (cleanRelative.startsWith('./')) {
+  if (cleanRelative.startsWith('./') || cleanRelative.startsWith('.\\')) {
     cleanRelative = cleanRelative.slice(2);
   }
 
   // Handle ../ prefixes (parent directory)
   const separator = cleanBase.includes('\\') ? '\\' : '/';
-  const hasUnixRoot = cleanBase.startsWith('/');
-  const hasUncRoot = cleanBase.startsWith('\\\\');
+  const hasUncRoot = cleanBase.startsWith('\\\\') || cleanBase.startsWith('//');
+  const hasUnixRoot = !hasUncRoot && cleanBase.startsWith('/');
+  const minRootParts = hasUncRoot ? 2 : 1;
   const normalizedRelative = normalizeSeparators(cleanRelative, separator);
   const baseParts = splitPath(cleanBase);
   let remainingRelative = normalizedRelative;
   while (remainingRelative.startsWith(`..${separator}`)) {
     remainingRelative = remainingRelative.slice(3);
-    if (baseParts.length > 1) {
+    if (baseParts.length > minRootParts) {
       baseParts.pop();
     }
   }
@@ -506,24 +508,12 @@ function joinPaths(base: string, relative: string): string {
   if (hasUnixRoot && !normalizedBase.startsWith('/')) {
     normalizedBase = `/${normalizedBase}`;
   }
-  if (hasUncRoot && !normalizedBase.startsWith('\\\\')) {
-    normalizedBase = `\\\\${normalizedBase}`;
+  if (hasUncRoot && !normalizedBase.startsWith(`${separator}${separator}`)) {
+    normalizedBase = `${separator}${separator}${normalizedBase}`;
   }
   return remainingRelative ? `${normalizedBase}${separator}${remainingRelative}` : normalizedBase;
 }
 
-function trimTrailingSeparator(input: string): string {
-  let end = input.length;
-  while (end > 0) {
-    const char = input[end - 1];
-    if (char !== '/' && char !== '\\') {
-      break;
-    }
-    end--;
-  }
-  return input.slice(0, end);
-}
-
 function normalizeSeparators(input: string, separator: '/' | '\\'): string {
   let output = '';
   let prevWasSeparator = false;
@@ -567,7 +557,50 @@ function splitPath(input: string): string[] {
 }
 
 function normalizeForComparison(input: string): string {
-  return input.replace(/\\/g, '/');
+  return normalizePathForComparison(input);
+}
+
+function createSeenPathSet(paths: string[]): Set<string> {
+  return new Set(paths.map(normalizeForComparison));
+}
+
+function hasSeenPath(seenPaths: Set<string>, path: string): boolean {
+  return seenPaths.has(normalizeForComparison(path));
+}
+
+function rememberPath(seenPaths: Set<string>, path: string): void {
+  seenPaths.add(normalizeForComparison(path));
+}
+
+function getRecordValueByPath<T>(
+  record: Record<string, T> | undefined,
+  path: string
+): T | undefined {
+  if (!record) return undefined;
+  const exact = record[path];
+  if (exact !== undefined) return exact;
+
+  const normalizedPath = normalizeForComparison(path);
+  for (const [key, value] of Object.entries(record)) {
+    if (normalizeForComparison(key) === normalizedPath) {
+      return value;
+    }
+  }
+  return undefined;
+}
+
+function getMapValueByPath<T>(map: Map<string, T> | undefined, path: string): T | undefined {
+  if (!map) return undefined;
+  const exact = map.get(path);
+  if (exact !== undefined) return exact;
+
+  const normalizedPath = normalizeForComparison(path);
+  for (const [key, value] of map.entries()) {
+    if (normalizeForComparison(key) === normalizedPath) {
+      return value;
+    }
+  }
+  return undefined;
 }
 
 /**
@@ -604,7 +637,7 @@ function computeContextStats(params: ComputeContextStatsParams): ContextStats {
   } = params;
 
   const newInjections: ContextInjection[] = [];
-  const previousPaths = new Set(
+  const previousPaths = createSeenPathSet(
     previousInjections
       .filter(
         (inj): inj is ClaudeMdContextInjection | MentionedFileInjection =>
@@ -620,9 +653,9 @@ function computeContextStats(params: ComputeContextStatsParams): ContextStats {
   if (isFirstGroup) {
     const globalInjections = createGlobalInjections(projectRoot, turnGroupId, claudeMdTokenData);
     for (const injection of globalInjections) {
-      if (!previousPaths.has(injection.path)) {
+      if (!hasSeenPath(previousPaths, injection.path)) {
         newInjections.push(wrapClaudeMdInjection(injection));
-        previousPaths.add(injection.path);
+        rememberPath(previousPaths, injection.path);
       }
     }
   }
@@ -654,7 +687,7 @@ function computeContextStats(params: ComputeContextStatsParams): ContextStats {
 
     for (const claudeMdPath of claudeMdPaths) {
       // Skip if already seen
-      if (previousPaths.has(claudeMdPath)) {
+      if (hasSeenPath(previousPaths, claudeMdPath)) {
         continue;
       }
 
@@ -674,7 +707,7 @@ function computeContextStats(params: ComputeContextStatsParams): ContextStats {
       // Only include directory CLAUDE.md files that exist (validated via directoryTokenData)
       // If directoryTokenData is provided and doesn't contain this path, the file doesn't exist
       if (directoryTokenData) {
-        const fileInfo = directoryTokenData[claudeMdPath];
+        const fileInfo = getRecordValueByPath(directoryTokenData, claudeMdPath);
         if (!fileInfo || !fileInfo.exists || fileInfo.estimatedTokens <= 0) {
           // File doesn't exist or has no content - skip it
           continue;
@@ -683,12 +716,12 @@ function computeContextStats(params: ComputeContextStatsParams): ContextStats {
         const injection = createDirectoryInjection(claudeMdPath, turnGroupId);
         injection.estimatedTokens = fileInfo.estimatedTokens;
         newInjections.push(wrapClaudeMdInjection(injection));
-        previousPaths.add(claudeMdPath);
+        rememberPath(previousPaths, claudeMdPath);
       } else {
         // Fallback: if no directoryTokenData provided, create with default tokens (legacy behavior)
         const injection = createDirectoryInjection(claudeMdPath, turnGroupId);
         newInjections.push(wrapClaudeMdInjection(injection));
-        previousPaths.add(claudeMdPath);
+        rememberPath(previousPaths, claudeMdPath);
       }
     }
   }
@@ -704,12 +737,12 @@ function computeContextStats(params: ComputeContextStatsParams): ContextStats {
         : joinPaths(projectRoot, fileRef.path);
 
       // Skip if already seen
-      if (previousPaths.has(absolutePath)) {
+      if (hasSeenPath(previousPaths, absolutePath)) {
         continue;
       }
 
       // Check if we have token data for this file
-      const fileInfo = mentionedFileTokenData?.get(absolutePath);
+      const fileInfo = getMapValueByPath(mentionedFileTokenData, absolutePath);
 
       // Only include files that exist and are under the token limit
       if (fileInfo && fileInfo.exists && fileInfo.estimatedTokens <= MAX_MENTIONED_FILE_TOKENS) {
@@ -723,7 +756,7 @@ function computeContextStats(params: ComputeContextStatsParams): ContextStats {
         });
 
         newInjections.push(mentionedFileInjection);
-        previousPaths.add(absolutePath);
+        rememberPath(previousPaths, absolutePath);
       }
     }
   }
@@ -736,11 +769,11 @@ function computeContextStats(params: ComputeContextStatsParams): ContextStats {
       ? fileRef.path
       : joinPaths(projectRoot, fileRef.path);
 
-    if (previousPaths.has(absolutePath)) {
+    if (hasSeenPath(previousPaths, absolutePath)) {
       continue;
     }
 
-    const fileInfo = mentionedFileTokenData?.get(absolutePath);
+    const fileInfo = getMapValueByPath(mentionedFileTokenData, absolutePath);
 
     if (fileInfo && fileInfo.exists && fileInfo.estimatedTokens <= MAX_MENTIONED_FILE_TOKENS) {
       const mentionedFileInjection = createMentionedFileInjection({
@@ -753,7 +786,7 @@ function computeContextStats(params: ComputeContextStatsParams): ContextStats {
       });
 
       newInjections.push(mentionedFileInjection);
-      previousPaths.add(absolutePath);
+      rememberPath(previousPaths, absolutePath);
     }
   }
 
diff --git a/src/renderer/utils/pathDisplay.ts b/src/renderer/utils/pathDisplay.ts
index ccdd6808..a9955671 100644
--- a/src/renderer/utils/pathDisplay.ts
+++ b/src/renderer/utils/pathDisplay.ts
@@ -9,7 +9,7 @@
  * Also provides resolveAbsolutePath() for clipboard copy (~ → real home, relative → absolute).
  */
 
-import { splitPath } from '@shared/utils/platformPath';
+import { getRelativePathWithinPrefix, splitPath } from '@shared/utils/platformPath';
 
 function isWindowsAbsolutePath(input: string): boolean {
   return /^[A-Za-z]:[/\\]/.test(input) || input.startsWith('\\\\') || input.startsWith('//');
@@ -38,15 +38,9 @@ export function shortenDisplayPath(fullPath: string, projectRoot?: string, maxLe
 
   // 1. Make relative to project root
   if (projectRoot) {
-    const root = projectRoot.replace(/[/\\]$/, '');
-    const caseInsensitive = isWindowsAbsolutePath(p) || isWindowsAbsolutePath(root);
-    const pathForCompare = caseInsensitive ? p.toLowerCase() : p;
-    const rootForCompare = caseInsensitive ? root.toLowerCase() : root;
-    if (
-      pathForCompare.startsWith(rootForCompare + '/') ||
-      pathForCompare.startsWith(rootForCompare + '\\')
-    ) {
-      p = p.slice(root.length + 1);
+    const relativePath = getRelativePathWithinPrefix(projectRoot, p);
+    if (relativePath) {
+      p = relativePath;
     }
   }
 
@@ -54,7 +48,7 @@ export function shortenDisplayPath(fullPath: string, projectRoot?: string, maxLe
   p = p
     .replace(/^\/Users\/[^/]+/, '~')
     .replace(/^\/home\/[^/]+/, '~')
-    .replace(/^[A-Z]:\\Users\\[^\\]+/i, '~');
+    .replace(/^[A-Z]:[/\\]Users[/\\][^/\\]+/i, '~');
 
   // 3. If short enough, return as-is
   if (p.length <= maxLength) return p;
@@ -84,7 +78,7 @@ function inferHomeDir(projectRoot: string): string | null {
   const match =
     /^(\/Users\/[^/]+)/.exec(projectRoot) ??
     /^(\/home\/[^/]+)/.exec(projectRoot) ??
-    /^([A-Z]:\\Users\\[^\\]+)/i.exec(projectRoot);
+    /^([A-Z]:[/\\]Users[/\\][^/\\]+)/i.exec(projectRoot);
   return match?.[1] ?? null;
 }
 
@@ -122,11 +116,7 @@ export function formatProjectPath(path: string): string {
 }
 
 function isWindowsUserPath(input: string): boolean {
-  if (input.length < 10) return false;
-  const drive = input.charCodeAt(0);
-  const hasDriveLetter =
-    ((drive >= 65 && drive <= 90) || (drive >= 97 && drive <= 122)) && input[1] === ':';
-  return hasDriveLetter && input.slice(2, 9).toLowerCase() === '\\users\\';
+  return /^[A-Z]:[/\\]Users[/\\]/i.test(input);
 }
 
 export function resolveAbsolutePath(filePath: string, projectRoot?: string): string {
diff --git a/src/shared/utils/platformPath.ts b/src/shared/utils/platformPath.ts
index 82f0c0aa..03eacb2f 100644
--- a/src/shared/utils/platformPath.ts
+++ b/src/shared/utils/platformPath.ts
@@ -78,6 +78,7 @@ export function joinPath(base: string, ...segments: string[]): string {
 export function isPathPrefix(prefix: string, fullPath: string): boolean {
   const p = stripTrailingSeparators(normalizePathForComparison(prefix));
   const f = stripTrailingSeparators(normalizePathForComparison(fullPath));
+  if (!p) return false;
   if (f === p) return true;
   // Root prefixes are special: p already ends with "/" ("/" or "c:/").
   if (p === '/') return f.startsWith('/');
@@ -85,6 +86,26 @@ export function isPathPrefix(prefix: string, fullPath: string): boolean {
   return f.startsWith(p + '/');
 }
 
+/** Return fullPath relative to prefix when fullPath is inside prefix, preserving fullPath style. */
+export function getRelativePathWithinPrefix(prefix: string, fullPath: string): string | null {
+  const cleanPrefix = stripTrailingSeparators(prefix);
+  if (!isPathPrefix(cleanPrefix, fullPath)) {
+    return null;
+  }
+
+  const normalizedPrefix = stripTrailingSeparators(normalizePathForComparison(cleanPrefix));
+  const normalizedFullPath = stripTrailingSeparators(normalizePathForComparison(fullPath));
+  if (normalizedFullPath === normalizedPrefix) {
+    return '';
+  }
+
+  let relativePath = fullPath.slice(cleanPrefix.length);
+  while (relativePath.startsWith('/') || relativePath.startsWith('\\')) {
+    relativePath = relativePath.slice(1);
+  }
+  return relativePath;
+}
+
 /** Get the last segment (filename) from a path. */
 export function getBasename(filePath: string): string {
   const parts = splitPath(filePath);
diff --git a/test/features/recent-projects/renderer/utils/recentProjectOpenHistory.test.ts b/test/features/recent-projects/renderer/utils/recentProjectOpenHistory.test.ts
index 147ae8b6..98ddb38f 100644
--- a/test/features/recent-projects/renderer/utils/recentProjectOpenHistory.test.ts
+++ b/test/features/recent-projects/renderer/utils/recentProjectOpenHistory.test.ts
@@ -129,6 +129,20 @@ describe('recentProjectOpenHistory', () => {
     ).toBe(0);
   });
 
+  it('collapses Windows drive-case and separator variants', () => {
+    recordRecentProjectOpenPaths(['C:\\Work\\Repo'], 5_000);
+    recordRecentProjectOpenPaths(['c:/work/repo/'], 8_000);
+
+    expect(
+      getRecentProjectLastOpenedAt(
+        makeProject({
+          primaryPath: 'C:/WORK/REPO',
+          associatedPaths: ['C:/WORK/REPO'],
+        })
+      )
+    ).toBe(8_000);
+  });
+
   it('does not record generated ephemeral project paths', () => {
     recordRecentProjectOpenPaths(
       ['/private/var/folders/7b/cache/T/codex-agent-teams-appstyle-zudek6i9', '/workspace/opened'],
@@ -152,4 +166,9 @@ describe('recentProjectOpenHistory', () => {
       )
     ).toBe(10_000);
   });
+
+  it('ignores blank project paths without throwing', () => {
+    expect(() => recordRecentProjectOpenPaths(['  '], 10_000)).not.toThrow();
+    expect(getRecentProjectLastOpenedAt(makeProject({ primaryPath: '  ', associatedPaths: ['  '] }))).toBe(0);
+  });
 });
diff --git a/test/main/build/electronBuilderAfterPack.test.ts b/test/main/build/electronBuilderAfterPack.test.ts
index 7b8428e4..8835dbfc 100644
--- a/test/main/build/electronBuilderAfterPack.test.ts
+++ b/test/main/build/electronBuilderAfterPack.test.ts
@@ -45,8 +45,8 @@ function createElfBuffer(arch: 'arm64' | 'x64'): Buffer {
   return buffer;
 }
 
-function createPortableExecutableBuffer(arch: 'arm64' | 'x64'): Buffer {
-  const machine = arch === 'arm64' ? 0xaa64 : 0x8664;
+function createPortableExecutableBuffer(arch: 'arm64' | 'ia32' | 'x64'): Buffer {
+  const machine = arch === 'arm64' ? 0xaa64 : arch === 'ia32' ? 0x014c : 0x8664;
   const buffer = Buffer.alloc(256);
   buffer[0] = 0x4d;
   buffer[1] = 0x5a;
@@ -224,4 +224,72 @@ describe('electron-builder afterPack', () => {
       )
     ).toBe(false);
   });
+
+  it('accepts a clean x64 Windows bundle with optional standalone helper binaries', async () => {
+    const tempDir = createTempDir();
+    tempDirs.push(tempDir);
+
+    writeFile(path.join(tempDir, 'Agent Teams UI.exe'), createPortableExecutableBuffer('x64'));
+    writeFile(
+      path.join(
+        tempDir,
+        'resources',
+        'app.asar.unpacked',
+        'node_modules',
+        'node-pty',
+        'build',
+        'Release',
+        'pty.node'
+      ),
+      createPortableExecutableBuffer('x64')
+    );
+    const pageantPath = path.join(
+      tempDir,
+      'resources',
+      'app.asar.unpacked',
+      'node_modules',
+      'ssh2',
+      'util',
+      'pagent.exe'
+    );
+    const armConptyDir = path.join(
+      tempDir,
+      'resources',
+      'app.asar.unpacked',
+      'node_modules',
+      'node-pty',
+      'third_party',
+      'conpty',
+      '1.23.251008001',
+      'win10-arm64'
+    );
+    writeFile(pageantPath, createPortableExecutableBuffer('ia32'));
+    writeFile(path.join(armConptyDir, 'conpty.dll'), createPortableExecutableBuffer('arm64'));
+    writeFile(path.join(armConptyDir, 'OpenConsole.exe'), createPortableExecutableBuffer('arm64'));
+
+    await afterPackModule({
+      appOutDir: tempDir,
+      electronPlatformName: 'win32',
+      arch: 1,
+    });
+
+    expect(fs.existsSync(pageantPath)).toBe(true);
+    expect(fs.existsSync(armConptyDir)).toBe(false);
+  });
+
+  it('still reports unrelated ia32 Windows binaries in an x64 bundle', async () => {
+    const tempDir = createTempDir();
+    tempDirs.push(tempDir);
+
+    const badBinaryPath = path.join(tempDir, 'resources', 'app.asar.unpacked', 'bad-helper.exe');
+    writeFile(badBinaryPath, createPortableExecutableBuffer('ia32'));
+
+    await expect(validateNativeBinaries(tempDir, 'win32', 'x64')).resolves.toEqual([
+      {
+        path: path.join('resources', 'app.asar.unpacked', 'bad-helper.exe'),
+        format: 'pe',
+        archs: ['ia32'],
+      },
+    ]);
+  });
 });
diff --git a/test/main/build/electronBuilderDistScript.test.ts b/test/main/build/electronBuilderDistScript.test.ts
index dcb80d48..79ae4377 100644
--- a/test/main/build/electronBuilderDistScript.test.ts
+++ b/test/main/build/electronBuilderDistScript.test.ts
@@ -1,14 +1,10 @@
 // @vitest-environment node
-import { pathToFileURL } from 'node:url';
-
 import { describe, expect, it } from 'vitest';
 
-const scriptUrl = pathToFileURL(`${process.cwd()}/scripts/electron-builder/dist.mjs`).href;
+const { buildElectronBuilderInvocations } = require('../../../scripts/electron-builder/dist-invocations.cjs');
 
 describe('electron-builder dist wrapper', () => {
   it('splits multi-platform builds so Linux-only package name overrides do not affect macOS or Windows', async () => {
-    const { buildElectronBuilderInvocations } = await import(scriptUrl);
-
     expect(
       buildElectronBuilderInvocations(['--mac', '--win', '--linux', '--publish', 'never'])
     ).toEqual([
@@ -27,8 +23,6 @@ describe('electron-builder dist wrapper', () => {
   });
 
   it('adds the filesystem-safe package name override to Linux-only builds', async () => {
-    const { buildElectronBuilderInvocations } = await import(scriptUrl);
-
     expect(buildElectronBuilderInvocations(['--linux', '--publish', 'never'])).toEqual([
       {
         args: [
@@ -43,8 +37,6 @@ describe('electron-builder dist wrapper', () => {
   });
 
   it('leaves macOS arch-specific builds unchanged', async () => {
-    const { buildElectronBuilderInvocations } = await import(scriptUrl);
-
     expect(buildElectronBuilderInvocations(['--mac', '--arm64', '--publish', 'never'])).toEqual([
       { args: ['--mac', '--arm64', '--publish', 'never'] },
     ]);
diff --git a/test/main/services/editor/FileSearchService.test.ts b/test/main/services/editor/FileSearchService.test.ts
index f9fa4d45..956580d2 100644
--- a/test/main/services/editor/FileSearchService.test.ts
+++ b/test/main/services/editor/FileSearchService.test.ts
@@ -6,6 +6,7 @@ import * as path from 'path';
 import { beforeEach, describe, expect, it, vi } from 'vitest';
 
 vi.mock('fs/promises', () => ({
+  access: vi.fn(),
   readdir: vi.fn(),
   readFile: vi.fn(),
   stat: vi.fn(),
@@ -36,6 +37,7 @@ describe('FileSearchService', () => {
 
   beforeEach(() => {
     vi.resetAllMocks();
+    vi.mocked(fs.access).mockRejectedValue(new Error('not a git repository') as never);
     service = new FileSearchService();
   });
 
@@ -173,4 +175,27 @@ describe('FileSearchService', () => {
     expect(result.results[0].matches[1].column).toBe(4);
     expect(result.results[0].matches[2].column).toBe(8);
   });
+
+  it('returns slash-normalized relative paths for quick open on Windows', async () => {
+    vi.mocked(fs.readdir).mockImplementation(async (dirPath: unknown) => {
+      const normalized = path.normalize(String(dirPath));
+      if (normalized === path.normalize(PROJECT_ROOT)) {
+        return [{ name: 'src', isFile: () => false, isDirectory: () => true }] as never;
+      }
+      if (normalized === path.normalize(path.join(PROJECT_ROOT, 'src'))) {
+        return [{ name: 'app.ts', isFile: () => true, isDirectory: () => false }] as never;
+      }
+      return [] as never;
+    });
+
+    const files = await service.listFiles(PROJECT_ROOT);
+
+    expect(files).toEqual([
+      {
+        path: path.join(PROJECT_ROOT, 'src', 'app.ts'),
+        name: 'app.ts',
+        relativePath: 'src/app.ts',
+      },
+    ]);
+  });
 });
diff --git a/test/renderer/components/chat/SessionContextPanel/buildDirectoryTree.test.ts b/test/renderer/components/chat/SessionContextPanel/buildDirectoryTree.test.ts
new file mode 100644
index 00000000..bd7e1205
--- /dev/null
+++ b/test/renderer/components/chat/SessionContextPanel/buildDirectoryTree.test.ts
@@ -0,0 +1,47 @@
+import { describe, expect, it } from 'vitest';
+
+import { buildDirectoryTree } from '@renderer/components/chat/SessionContextPanel/DirectoryTree/buildDirectoryTree';
+
+import type { ClaudeMdContextInjection } from '@renderer/types/contextInjection';
+
+function injection(path: string): ClaudeMdContextInjection {
+  return {
+    id: path,
+    category: 'claude-md',
+    path,
+    source: 'directory',
+    displayName: 'CLAUDE.md',
+    isGlobal: false,
+    estimatedTokens: 12,
+    firstSeenInGroup: 'ai-0',
+  };
+}
+
+describe('buildDirectoryTree Windows paths', () => {
+  it('strips project root case-insensitively for Windows paths with mixed separators', () => {
+    const root = buildDirectoryTree(
+      [injection('c:\\Users\\Alice\\repo\\src\\CLAUDE.md')],
+      'C:/Users/Alice/Repo'
+    );
+
+    expect(root.children.has('c:')).toBe(false);
+    expect(root.children.get('src')?.children.get('CLAUDE.md')?.path).toBe(
+      'c:\\Users\\Alice\\repo\\src\\CLAUDE.md'
+    );
+  });
+
+  it('does not strip sibling paths that only share a prefix', () => {
+    const root = buildDirectoryTree(
+      [injection('C:\\Users\\Alice\\Repo2\\CLAUDE.md')],
+      'C:\\Users\\Alice\\Repo'
+    );
+
+    expect(root.children.get('C:')?.children.get('Users')).toBeDefined();
+  });
+
+  it('falls back to the injection path when project root is empty', () => {
+    const root = buildDirectoryTree([injection('C:\\Users\\Alice\\Repo\\CLAUDE.md')], '');
+
+    expect(root.children.get('C:')?.children.get('Users')).toBeDefined();
+  });
+});
diff --git a/test/renderer/components/chat/viewers/MarkdownViewer.test.tsx b/test/renderer/components/chat/viewers/MarkdownViewer.test.tsx
index 2ed11137..42c8218d 100644
--- a/test/renderer/components/chat/viewers/MarkdownViewer.test.tsx
+++ b/test/renderer/components/chat/viewers/MarkdownViewer.test.tsx
@@ -40,7 +40,10 @@ vi.mock('@renderer/components/chat/viewers/FileLink', () => ({
   isRelativeUrl: () => false,
 }));
 
-import { MarkdownViewer } from '@renderer/components/chat/viewers/MarkdownViewer';
+import {
+  MarkdownViewer,
+  resolveRelativePath,
+} from '@renderer/components/chat/viewers/MarkdownViewer';
 
 describe('MarkdownViewer code blocks', () => {
   afterEach(() => {
@@ -89,3 +92,23 @@ describe('MarkdownViewer code blocks', () => {
     });
   });
 });
+
+describe('MarkdownViewer local image path resolution', () => {
+  it('resolves Windows relative image paths against a Windows base directory', () => {
+    expect(resolveRelativePath('.\\images\\plot.png', 'C:\\Repo\\docs')).toBe(
+      'C:\\Repo\\docs\\images\\plot.png'
+    );
+  });
+
+  it('preserves absolute Windows image paths', () => {
+    expect(resolveRelativePath('C:\\Screens\\plot.png', 'C:\\Repo\\docs')).toBe(
+      'C:\\Screens\\plot.png'
+    );
+  });
+
+  it('resolves Windows UNC parent image paths without escaping the share root', () => {
+    expect(resolveRelativePath('..\\assets\\plot.png', '\\\\server\\share\\repo\\docs')).toBe(
+      '\\\\server\\share\\repo\\assets\\plot.png'
+    );
+  });
+});
diff --git a/test/renderer/components/fileLink.test.ts b/test/renderer/components/fileLink.test.ts
index 851b3bd2..94edc29a 100644
--- a/test/renderer/components/fileLink.test.ts
+++ b/test/renderer/components/fileLink.test.ts
@@ -121,4 +121,19 @@ describe('resolveFileLinkPath', () => {
       resolveFileLinkPath('/Users/belief/dev/projects/your_posts/docs/roadmap.md', PROJECT_PATH)
     ).toBe('/Users/belief/dev/projects/your_posts/docs/roadmap.md');
   });
+
+  it('preserves Windows UNC roots when normalizing path segments', () => {
+    expect(resolveFileLinkPath('\\\\server\\share\\repo\\..\\docs\\roadmap.md', PROJECT_PATH)).toBe(
+      '\\\\server\\share\\docs\\roadmap.md'
+    );
+    expect(resolveFileLinkPath('//server/share/repo/../docs/roadmap.md', PROJECT_PATH)).toBe(
+      '//server/share/docs/roadmap.md'
+    );
+  });
+
+  it('preserves Windows drive roots when normalizing dot segments', () => {
+    expect(resolveFileLinkPath('C:\\repo\\src\\..\\README.md', PROJECT_PATH)).toBe(
+      'C:\\repo\\README.md'
+    );
+  });
 });
diff --git a/test/renderer/hooks/useFileSuggestions.test.ts b/test/renderer/hooks/useFileSuggestions.test.ts
index 1f916937..1b9744cf 100644
--- a/test/renderer/hooks/useFileSuggestions.test.ts
+++ b/test/renderer/hooks/useFileSuggestions.test.ts
@@ -1,6 +1,11 @@
 import { describe, expect, it } from 'vitest';
 
-import { filterFileSuggestions, formatFileMentionPath } from '@renderer/hooks/useFileSuggestions';
+import {
+  extractDirectories,
+  filterFileSuggestions,
+  filterFolderSuggestions,
+  formatFileMentionPath,
+} from '@renderer/hooks/useFileSuggestions';
 
 import type { QuickOpenFile } from '@shared/types/editor';
 
@@ -91,14 +96,42 @@ describe('filterFileSuggestions', () => {
     expect(results.map((r) => r.name)).toEqual(['auth.ts', 'database.ts']);
   });
 
+  it('matches Windows backslash queries against normalized relative paths', () => {
+    const results = filterFileSuggestions(FILES, 'services\\auth');
+    expect(results).toHaveLength(1);
+    expect(results[0].relativePath).toBe('src/services/auth.ts');
+  });
+
   it('returns results in file list order', () => {
     const results = filterFileSuggestions(FILES, '.ts');
     expect(results[0].name).toBe('index.ts');
   });
 
   it('quotes inserted paths that contain spaces', () => {
-    expect(formatFileMentionPath('src/My Component/App.tsx')).toBe(
-      '"src/My Component/App.tsx"'
-    );
+    expect(formatFileMentionPath('src/My Component/App.tsx')).toBe('"src/My Component/App.tsx"');
+  });
+});
+
+describe('folder suggestions', () => {
+  it('derives stable folders from Windows relative paths', () => {
+    const folders = extractDirectories(
+      [
+        {
+          name: 'auth.ts',
+          relativePath: 'src\\services\\auth.ts',
+          path: 'C:\\Repo\\src\\services\\auth.ts',
+        },
+      ],
+      'C:\\Repo'
+    );
+
+    expect(folders.map((f) => [f.name, f.relativePath, f.absolutePath])).toEqual([
+      ['src', 'src/', 'C:\\Repo\\src'],
+      ['services', 'src/services/', 'C:\\Repo\\src\\services'],
+    ]);
+
+    const suggestions = filterFolderSuggestions(folders, 'src\\services\\');
+    expect(suggestions).toHaveLength(1);
+    expect(suggestions[0].insertText).toBe('src/services/');
   });
 });
diff --git a/test/renderer/store/pathResolution.test.ts b/test/renderer/store/pathResolution.test.ts
index 19de8fad..218390dc 100644
--- a/test/renderer/store/pathResolution.test.ts
+++ b/test/renderer/store/pathResolution.test.ts
@@ -13,6 +13,7 @@ describe('resolveFilePath', () => {
 
   it('resolves dot-prefixed relative paths', () => {
     expect(resolveFilePath('/repo', './src/app.ts')).toBe('/repo/src/app.ts');
+    expect(resolveFilePath('C:\\repo', '.\\src\\app.ts')).toBe('C:\\repo\\src\\app.ts');
   });
 
   it('resolves parent relative paths on unix', () => {
@@ -27,6 +28,11 @@ describe('resolveFilePath', () => {
     );
   });
 
+  it('preserves Windows drive-root separators when resolving child paths', () => {
+    expect(resolveFilePath('C:\\', 'src\\app.ts')).toBe('C:\\src\\app.ts');
+    expect(resolveFilePath('C:/', 'src/app.ts')).toBe('C:/src/app.ts');
+  });
+
   it('passes through tilde paths as-is', () => {
     expect(resolveFilePath('/repo', '~/some/directory')).toBe('~/some/directory');
   });
@@ -45,6 +51,24 @@ describe('resolveFilePath', () => {
     );
   });
 
+  it('resolves relative paths under Windows UNC roots', () => {
+    expect(resolveFilePath('\\\\server\\share\\repo', 'src\\index.ts')).toBe(
+      '\\\\server\\share\\repo\\src\\index.ts'
+    );
+    expect(resolveFilePath('//server/share/repo', 'src/index.ts')).toBe(
+      '//server/share/repo/src/index.ts'
+    );
+  });
+
+  it('does not resolve parent paths above a Windows UNC share root', () => {
+    expect(resolveFilePath('\\\\server\\share', '..\\outside\\file.ts')).toBe(
+      '\\\\server\\share\\outside\\file.ts'
+    );
+    expect(resolveFilePath('//server/share', '../outside/file.ts')).toBe(
+      '//server/share/outside/file.ts'
+    );
+  });
+
   it('does not treat tilde in the middle as special', () => {
     expect(resolveFilePath('/repo', 'foo~/bar')).toBe('/repo/foo~/bar');
   });
diff --git a/test/renderer/utils/claudeMdTracker.test.ts b/test/renderer/utils/claudeMdTracker.test.ts
index 6e23567e..32f2199d 100644
--- a/test/renderer/utils/claudeMdTracker.test.ts
+++ b/test/renderer/utils/claudeMdTracker.test.ts
@@ -2,8 +2,10 @@ import { describe, expect, it } from 'vitest';
 
 import {
   detectClaudeMdFromFilePath,
+  extractUserMentionPaths,
   getDirectory,
   getParentDirectory,
+  processSessionClaudeMd,
 } from '@renderer/utils/claudeMdTracker';
 
 describe('claudeMdTracker path helpers', () => {
@@ -67,6 +69,13 @@ describe('claudeMdTracker path helpers', () => {
       expect(result).toHaveLength(2);
     });
 
+    it('detects CLAUDE.md files for Windows paths with drive-case and separator differences', () => {
+      const result = detectClaudeMdFromFilePath('c:\\Repo\\src\\file.ts', 'C:/repo');
+      expect(result).toContain('c:\\Repo\\src\\CLAUDE.md');
+      expect(result).toContain('c:\\Repo\\CLAUDE.md');
+      expect(result).toHaveLength(2);
+    });
+
     it('uses correct separator for generated paths', () => {
       const unixResult = detectClaudeMdFromFilePath('/repo/src/file.ts', '/repo');
       for (const p of unixResult) {
@@ -93,3 +102,97 @@ describe('claudeMdTracker path helpers', () => {
     });
   });
 });
+
+describe('processSessionClaudeMd Windows paths', () => {
+  function aiReadGroup(id: string, turnIndex: number, filePath: string) {
+    return {
+      id,
+      turnIndex,
+      startTime: new Date(0),
+      endTime: new Date(0),
+      durationMs: 0,
+      steps: [
+        {
+          type: 'tool_call',
+          content: {
+            toolName: 'Read',
+            toolInput: { file_path: filePath },
+          },
+        },
+      ],
+      tokens: { input: 1000, output: 0, cached: 0 },
+      summary: {
+        toolCallCount: 1,
+        outputMessageCount: 0,
+        subagentCount: 0,
+        totalDurationMs: 0,
+        totalTokens: 1000,
+        outputTokens: 0,
+        cachedTokens: 0,
+      },
+      status: 'complete',
+      processes: [],
+      chunkId: id,
+      metrics: {},
+      responses: [],
+    } as any;
+  }
+
+  it('dedupes directory CLAUDE.md paths across Windows case and separator differences', () => {
+    const stats = processSessionClaudeMd(
+      [
+        { type: 'ai', group: aiReadGroup('ai-0', 0, 'C:\\Repo\\src\\file.ts') },
+        { type: 'ai', group: aiReadGroup('ai-1', 1, 'c:/repo/src/other.ts') },
+      ],
+      'C:\\Repo'
+    );
+
+    const firstDirectories = stats
+      .get('ai-0')!
+      .newInjections.filter((injection) => injection.source === 'directory')
+      .map((injection) => injection.path);
+    const secondDirectories = stats
+      .get('ai-1')!
+      .newInjections.filter((injection) => injection.source === 'directory');
+
+    expect(firstDirectories).toEqual(['C:\\Repo\\src\\CLAUDE.md']);
+    expect(secondDirectories).toEqual([]);
+  });
+});
+
+describe('extractUserMentionPaths Windows paths', () => {
+  function userGroupWithPath(path: string) {
+    return {
+      content: {
+        fileReferences: [{ path, raw: `@${path}` }],
+      },
+    } as any;
+  }
+
+  it('resolves Windows current-directory mentions with backslash separators', () => {
+    expect(extractUserMentionPaths(userGroupWithPath('.\\src\\app.ts'), 'C:\\Repo')).toEqual([
+      'C:\\Repo\\src\\app.ts',
+    ]);
+  });
+
+  it('preserves Windows drive-root separators for relative mentions', () => {
+    expect(extractUserMentionPaths(userGroupWithPath('src\\app.ts'), 'C:\\')).toEqual([
+      'C:\\src\\app.ts',
+    ]);
+  });
+
+  it('resolves relative mentions under UNC roots without escaping the share root', () => {
+    expect(
+      extractUserMentionPaths(userGroupWithPath('../outside/file.ts'), '//server/share')
+    ).toEqual(['//server/share/outside/file.ts']);
+    expect(
+      extractUserMentionPaths(userGroupWithPath('..\\outside\\file.ts'), '\\\\server\\share')
+    ).toEqual(['\\\\server\\share\\outside\\file.ts']);
+  });
+
+  it('leaves home-relative mentions untouched', () => {
+    expect(extractUserMentionPaths(userGroupWithPath('~\\.claude\\CLAUDE.md'), 'C:\\Repo')).toEqual(
+      ['~\\.claude\\CLAUDE.md']
+    );
+  });
+});
diff --git a/test/renderer/utils/contextTracker.test.ts b/test/renderer/utils/contextTracker.test.ts
new file mode 100644
index 00000000..ae2a04c6
--- /dev/null
+++ b/test/renderer/utils/contextTracker.test.ts
@@ -0,0 +1,66 @@
+import { describe, expect, it } from 'vitest';
+
+import { processSessionContextWithPhases } from '@renderer/utils/contextTracker';
+
+function aiReadGroup(id: string, turnIndex: number, filePath: string) {
+  return {
+    id,
+    turnIndex,
+    startTime: new Date(0),
+    endTime: new Date(0),
+    durationMs: 0,
+    steps: [
+      {
+        type: 'tool_call',
+        content: {
+          toolName: 'Read',
+          toolInput: { file_path: filePath },
+        },
+      },
+    ],
+    tokens: { input: 1000, output: 0, cached: 0 },
+    summary: {
+      toolCallCount: 1,
+      outputMessageCount: 0,
+      subagentCount: 0,
+      totalDurationMs: 0,
+      totalTokens: 1000,
+      outputTokens: 0,
+      cachedTokens: 0,
+    },
+    status: 'complete',
+    processes: [],
+    chunkId: id,
+    metrics: {},
+    responses: [],
+    linkedTools: new Map(),
+    displayItems: [],
+  } as any;
+}
+
+describe('processSessionContextWithPhases Windows paths', () => {
+  it('matches validated directory CLAUDE.md data across drive-case and separator differences', () => {
+    const { statsMap } = processSessionContextWithPhases(
+      [{ type: 'ai', group: aiReadGroup('ai-0', 0, 'c:/repo/src/file.ts') }],
+      'C:\\Repo',
+      undefined,
+      undefined,
+      {
+        'C:\\Repo\\src\\CLAUDE.md': {
+          path: 'C:\\Repo\\src\\CLAUDE.md',
+          exists: true,
+          charCount: 492,
+          estimatedTokens: 123,
+        },
+      }
+    );
+
+    const directoryInjection = statsMap
+      .get('ai-0')!
+      .newInjections.find(
+        (injection) => injection.category === 'claude-md' && injection.source === 'directory'
+      );
+
+    expect(directoryInjection?.estimatedTokens).toBe(123);
+  });
+});
diff --git a/test/renderer/utils/pathDisplay.test.ts b/test/renderer/utils/pathDisplay.test.ts
index 20c5976b..f476bf16 100644
--- a/test/renderer/utils/pathDisplay.test.ts
+++ b/test/renderer/utils/pathDisplay.test.ts
@@ -8,25 +8,44 @@ import {
 
 describe('pathDisplay Windows paths', () => {
   it('treats lowercase drive paths as absolute', () => {
-    expect(resolveAbsolutePath('c:\\Users\\Alice\\repo\\src\\app.ts', 'C:\\Users\\Alice\\repo')).toBe(
-      'c:\\Users\\Alice\\repo\\src\\app.ts'
-    );
+    expect(
+      resolveAbsolutePath('c:\\Users\\Alice\\repo\\src\\app.ts', 'C:\\Users\\Alice\\repo')
+    ).toBe('c:\\Users\\Alice\\repo\\src\\app.ts');
   });
 
   it('shortens project-root relative paths case-insensitively on Windows', () => {
-    expect(shortenDisplayPath('c:\\Users\\Alice\\repo\\src\\app.ts', 'C:\\Users\\Alice\\Repo')).toBe(
+    expect(
+      shortenDisplayPath('c:\\Users\\Alice\\repo\\src\\app.ts', 'C:\\Users\\Alice\\Repo')
+    ).toBe('src\\app.ts');
+  });
+
+  it('shortens mixed-separator Windows paths without treating siblings as children', () => {
+    expect(shortenDisplayPath('c:\\Users\\Alice\\Repo\\src\\app.ts', 'C:/Users/Alice/repo')).toBe(
       'src\\app.ts'
     );
+    expect(
+      shortenDisplayPath('C:\\Users\\Alice\\Repo2\\src\\app.ts', 'C:\\Users\\Alice\\Repo')
+    ).toBe('~\\Repo2\\src\\app.ts');
   });
 
   it('formats lowercase Windows user paths with a home marker', () => {
     expect(formatProjectPath('c:\\users\\Alice\\repo')).toBe('~/repo');
+    expect(formatProjectPath('C:/Users/Alice/repo')).toBe('~/repo');
   });
 
   it('resolves home paths from lowercase Windows user roots', () => {
     expect(resolveAbsolutePath('~/repo/src/app.ts', 'c:\\users\\Alice\\workspace')).toBe(
       'c:\\users\\Alice\\repo\\src\\app.ts'
     );
+    expect(resolveAbsolutePath('~/repo/src/app.ts', 'C:/Users/Alice/workspace')).toBe(
+      'C:/Users/Alice/repo/src/app.ts'
+    );
+  });
+
+  it('shortens forward-slash Windows user paths with a home marker', () => {
+    expect(shortenDisplayPath('C:/Users/Alice/repo/src/app.ts', undefined, 80)).toBe(
+      '~/repo/src/app.ts'
+    );
   });
 
   it('resolves relative paths using the project root separator', () => {
diff --git a/test/shared/utils/platformPath.test.ts b/test/shared/utils/platformPath.test.ts
new file mode 100644
index 00000000..19d168cc
--- /dev/null
+++ b/test/shared/utils/platformPath.test.ts
@@ -0,0 +1,38 @@
+import { describe, expect, it } from 'vitest';
+
+import { getRelativePathWithinPrefix, isPathPrefix } from '../../../src/shared/utils/platformPath';
+
+describe('platformPath Windows containment', () => {
+  it('matches Windows drive paths case-insensitively and preserves child path style', () => {
+    expect(isPathPrefix('C:/Users/Alice/Repo', 'c:\\Users\\Alice\\repo\\src\\app.ts')).toBe(true);
+    expect(
+      getRelativePathWithinPrefix('C:/Users/Alice/Repo', 'c:\\Users\\Alice\\repo\\src\\app.ts')
+    ).toBe('src\\app.ts');
+  });
+
+  it('matches UNC paths with mixed separators', () => {
+    expect(
+      getRelativePathWithinPrefix('\\\\server\\share\\Repo', '//server/share/repo/src/app.ts')
+    ).toBe('src/app.ts');
+  });
+
+  it('rejects sibling paths that only share the same text prefix', () => {
+    expect(
+      getRelativePathWithinPrefix('C:\\Users\\Alice\\Repo', 'C:\\Users\\Alice\\Repo2\\x.ts')
+    ).toBe(null);
+  });
+
+  it('keeps POSIX paths case-sensitive', () => {
+    expect(getRelativePathWithinPrefix('/Users/Alice/Repo', '/Users/Alice/Repo/src/app.ts')).toBe(
+      'src/app.ts'
+    );
+    expect(getRelativePathWithinPrefix('/Users/Alice/Repo', '/Users/Alice/repo/src/app.ts')).toBe(
+      null
+    );
+  });
+
+  it('does not treat an empty prefix as the root of absolute paths', () => {
+    expect(isPathPrefix('', '/Users/Alice/Repo/src/app.ts')).toBe(false);
+    expect(getRelativePathWithinPrefix('', '/Users/Alice/Repo/src/app.ts')).toBe(null);
+  });
+});