### Preflight Checklist - [x] I have searched [existing issues](https://github.com/anthropics/claude-code/issues?q=is%3Aissue%20state%3Aopen%20label%3Abug) and this hasn't been reported yet - [x] This is a single bug report (please file separate reports for different bugs) - [x] I am using the latest version of Claude Code ### What's Wrong? # Bug Report: Skills Not Loading on Windows ## Summary Skills fail to load on Windows with error "Error: unknown skill" and "skill not registered with t

[BUG]

Resolved 💬 2 comments Opened Nov 14, 2025 by feijitong Closed Dec 27, 2025

Preflight Checklist

[x] I have searched existing issues and this hasn't been reported yet
[x] This is a single bug report (please file separate reports for different bugs)
[x] I am using the latest version of Claude Code

What's Wrong?

Bug Report: Skills Not Loading on Windows

Summary

Skills fail to load on Windows with error "Error: unknown skill" and "skill not registered with the system", while the same skills work on Linux/macOS.

Environment

OS: Windows 10/11 (windows32 2.6.2)
Claude Code Version: 2.0.37
Installation Type: Native installer
Working Directory: C:\Users\jmors\.claude

Problem Description

When attempting to invoke any skill using the Skill tool, Claude Code returns:

Error: unknown skill
skill not registered with the system

The debug logs show that 0 skills are being loaded despite having:

47+ custom user skills in C:\Users\jmors\.claude\skills\
Official Anthropic marketplace skills in C:\Users\jmors\.claude\plugins\marketplaces\anthropic-agent-skills\

Evidence from Debug Logs

From C:\Users\jmors\.claude\debug\86443684-052f-498d-9782-eb7e39a0b5da.txt:

[DEBUG] Loading skills from directories: managed=C:\ProgramData\ClaudeCode\.claude\skills, user=C:\Users\jmors\.claude\skills, project=C:\Users\jmors\.claude\.claude\skills
[DEBUG] >>>>> getPluginSkills CALLED <<<<<
[DEBUG] getPluginSkills: Processing 0 enabled plugins
[DEBUG] Total plugin skills loaded: 0
[DEBUG] Total plugin commands loaded: 0
[DEBUG] Loaded 0 unique skills (managed: 0, user: 0, project: 0, duplicates removed: 0)
[DEBUG] getSkillsIfEnabled returning: 0 skill dir commands, 0 plugin skills

Key observation: Line 19 shows Loaded 0 unique skills with all counts at 0.

Skills Are Properly Formatted

Verified that SKILL.md files have correct frontmatter:

Example 1: `skills/Research/Analytics/python-paper-implementation/SKILL.md`

---
name: python-paper-implementation
description: Translate academic papers in Economics (Ph.D. level), Actuarial Science (Ph.D./Actuary level), and Insurance into interactive Python applications using Dash/Plotly with dynamic widgets for parameter exploration. Use when implementing mathematical models from papers as web-based interactive dashboards, creating Python implementations of academic economics/actuarial models, or building Dash applications with sliders and real-time visualization for exploring paper results.
---

Example 2: Official Anthropic skill `plugins/marketplaces/anthropic-agent-skills/document-skills/pdf/SKILL.md`

---
name: pdf
description: Comprehensive PDF manipulation toolkit for extracting text and tables, creating new PDFs, merging/splitting documents, and handling forms. When Claude needs to fill in a PDF form or programmatically process, generate, or analyze PDF documents at scale.
license: Proprietary. LICENSE.txt has complete terms
---

File System Verification

Confirmed skills exist with proper structure:

$ find skills -name "SKILL.md" | wc -l
47

$ ls plugins/marketplaces/anthropic-agent-skills/document-skills/*/SKILL.md
plugins/marketplaces/anthropic-agent-skills/document-skills/docx/SKILL.md
plugins/marketplaces/anthropic-agent-skills/document-skills/pdf/SKILL.md
plugins/marketplaces/anthropic-agent-skills/document-skills/pptx/SKILL.md
plugins/marketplaces/anthropic-agent-skills/document-skills/xlsx/SKILL.md

Root Cause Hypothesis

This appears to be a Windows-specific path handling bug in the skill loader. Likely causes:

Using Unix-style path separators (/) in file search patterns on Windows
Not properly normalizing Windows paths with backslashes (\)
File glob pattern incompatibility with Windows filesystem API
Case-sensitivity assumptions that don't match Windows behavior

Expected Behavior

Skills should load successfully on Windows just as they do on Linux/macOS.

Actual Behavior

Zero skills are discovered/loaded, resulting in all skill invocations failing with "skill not registered with the system".

Impact

Complete inability to use custom skills on Windows
Complete inability to use official Anthropic marketplace skills on Windows
Feature parity broken between Windows and Linux/macOS

Reproduction Steps

Install Claude Code 2.0.37 on Windows
Create any SKILL.md file with proper frontmatter in %USERPROFILE%\.claude\skills\
Attempt to invoke the skill using the Skill tool
Observe error: "Error: unknown skill" and "skill not registered with the system"
Check debug logs showing Loaded 0 unique skills

Additional Context

Same skill files work correctly on Linux/macOS (confirmed by user)
Issue affects both user skills and official marketplace skills
Skills directory structure follows documentation standards
File permissions appear correct (readable by user)

Workaround

None available. Skills are completely non-functional on Windows until this bug is fixed.

What Should Happen?

Claude should load the skill properly

Error Messages/Logs

[DEBUG] Watching for changes in setting files C:\Users\jmors\.claude\settings.json...
[DEBUG] Using bash path: "C:\Program Files\Git\bin\bash.exe"
[DEBUG] [LSP MANAGER] initializeLspServerManager() called
[DEBUG] [LSP MANAGER] Created manager instance, state=pending
[DEBUG] [LSP MANAGER] Starting async initialization (generation 1)
[DEBUG] [LSP SERVER MANAGER] initialize() called
[DEBUG] [LSP SERVER MANAGER] Calling getAllLspServers()
[DEBUG] Found 0 plugins (0 enabled, 0 disabled)
[DEBUG] Total LSP servers loaded: 0
[DEBUG] [LSP SERVER MANAGER] getAllLspServers returned 0 server(s)
[DEBUG] LSP manager initialized with 0 servers
[DEBUG] LSP server manager initialized successfully
[DEBUG] LSP notification handlers registered successfully for all 0 server(s)
[DEBUG] Loading skills from directories: managed=C:\ProgramData\ClaudeCode\.claude\skills, user=C:\Users\jmors\.claude\skills, project=C:\Users\jmors\.claude\.claude\skills
[DEBUG] >>>>> getPluginSkills CALLED <<<<<
[DEBUG] getPluginSkills: Processing 0 enabled plugins
[DEBUG] Total plugin skills loaded: 0
[DEBUG] Total plugin commands loaded: 0
[DEBUG] Loaded 0 unique skills (managed: 0, user: 0, project: 0, duplicates removed: 0)
[DEBUG] getSkillsIfEnabled returning: 0 skill dir commands, 0 plugin skills
[DEBUG] Registered 0 hooks from 0 plugins
[DEBUG] Creating shell snapshot for bash (C:\Program Files\Git\bin\bash.exe)
[DEBUG] Looking for shell config file: C:\Users\jmors\.bashrc
[DEBUG] Shell config file not found: C:\Users\jmors\.bashrc, creating snapshot with Claude Code defaults only
[DEBUG] Snapshots directory: C:\Users\jmors\.claude\shell-snapshots
[DEBUG] Creating snapshot at: C:\Users\jmors\.claude\shell-snapshots\snapshot-bash-1763116579326-7eikl6.sh
[DEBUG] Shell binary exists: true
[DEBUG] Execution timeout: 10000ms
[DEBUG] Writing to temp file: C:\Users\jmors\.claude\todos\86443684-052f-498d-9782-eb7e39a0b5da-agent-86443684-052f-498d-9782-eb7e39a0b5da.json.tmp.6052.1763116579351
[DEBUG] Temp file written successfully, size: 2 bytes
[DEBUG] Renaming C:\Users\jmors\.claude\todos\86443684-052f-498d-9782-eb7e39a0b5da-agent-86443684-052f-498d-9782-eb7e39a0b5da.json.tmp.6052.1763116579351 to C:\Users\jmors\.claude\todos\86443684-052f-498d-9782-eb7e39a0b5da-agent-86443684-052f-498d-9782-eb7e39a0b5da.json
[DEBUG] File C:\Users\jmors\.claude\todos\86443684-052f-498d-9782-eb7e39a0b5da-agent-86443684-052f-498d-9782-eb7e39a0b5da.json written atomically
[DEBUG] Agent file C:\Users\jmors\.claude\agents\clauide marketplaces.md is missing required 'name' in frontmatter
[DEBUG] Failed to parse agent from C:\Users\jmors\.claude\agents\clauide marketplaces.md: Missing required "name" field in frontmatter
[DEBUG] Agent file C:\Users\jmors\.claude\agents\clauide marketplaces.md is missing required 'name' in frontmatter
[DEBUG] Failed to parse agent from C:\Users\jmors\.claude\agents\clauide marketplaces.md: Missing required "name" field in frontmatter
[DEBUG] Total plugin agents loaded: 0
[DEBUG] Ripgrep first use test: PASSED (mode=builtin, path=C:\Users\jmors\.local\bin\claude.exe)
[DEBUG] Writing to temp file: C:\Users\jmors\.claude.json.tmp.6052.1763116579988
[DEBUG] Preserving file permissions: 100666
[DEBUG] Temp file written successfully, size: 50493 bytes
[DEBUG] Applied original permissions to temp file
[DEBUG] Renaming C:\Users\jmors\.claude.json.tmp.6052.1763116579988 to C:\Users\jmors\.claude.json
[DEBUG] File C:\Users\jmors\.claude.json written atomically
[DEBUG] Getting matching hook commands for SessionStart with query: startup
[DEBUG] Found 0 hook matchers in settings
[DEBUG] Matched 0 unique hooks for query "startup" (0 before deduplication)
[DEBUG] Writing to temp file: C:\Users\jmors\.claude.json.tmp.6052.1763116580100
[DEBUG] Preserving file permissions: 100666
[DEBUG] Temp file written successfully, size: 50385 bytes
[DEBUG] Applied original permissions to temp file
[DEBUG] Renaming C:\Users\jmors\.claude.json.tmp.6052.1763116580100 to C:\Users\jmors\.claude.json
[DEBUG] File C:\Users\jmors\.claude.json written atomically
[DEBUG] Writing to temp file: C:\Users\jmors\.claude.json.tmp.6052.1763116580119
[DEBUG] Preserving file permissions: 100666
[DEBUG] Temp file written successfully, size: 50385 bytes
[DEBUG] Applied original permissions to temp file
[DEBUG] Renaming C:\Users\jmors\.claude.json.tmp.6052.1763116580119 to C:\Users\jmors\.claude.json
[DEBUG] File C:\Users\jmors\.claude.json written atomically
[DEBUG] AutoUpdaterWrapper: Installation type: native
[DEBUG] performStartupChecks called
[DEBUG] Starting background plugin installations
[DEBUG] performBackgroundPluginInstallations called
[DEBUG] Skills and commands included in Skill tool:
[DEBUG] Slash commands included in SlashCommand tool:
[DEBUG] Setting installation status: 0 marketplaces, 0 installable plugins, 0 uninstallable plugins
[DEBUG] Loaded plugins - Enabled: 0, Disabled: 0, Commands: 0, Agents: 0, Errors: 0
[DEBUG] Shell snapshot created successfully (283 bytes)
[DEBUG] Checking for native installer update to version 2.0.37
[DEBUG] Version 2.0.37 already installed, updating symlink
[DEBUG] Successfully updated to version 2.0.37
[DEBUG] Writing to temp file: C:\Users\jmors\.claude.json.tmp.6052.1763116580866
[DEBUG] Preserving file permissions: 100666
[DEBUG] Temp file written successfully, size: 50385 bytes
[DEBUG] Applied original permissions to temp file
[DEBUG] Renaming C:\Users\jmors\.claude.json.tmp.6052.1763116580866 to C:\Users\jmors\.claude.json
[DEBUG] File C:\Users\jmors\.claude.json written atomically
[DEBUG] Writing to temp file: C:\Users\jmors\.claude.json.tmp.6052.1763116580876
[DEBUG] Preserving file permissions: 100666
[DEBUG] Temp file written successfully, size: 50385 bytes
[DEBUG] Applied original permissions to temp file
[DEBUG] Renaming C:\Users\jmors\.claude.json.tmp.6052.1763116580876 to C:\Users\jmors\.claude.json
[DEBUG] File C:\Users\jmors\.claude.json written atomically
[DEBUG] Writing to temp file: C:\Users\jmors\.claude.json.tmp.6052.1763116580889
[DEBUG] Preserving file permissions: 100666
[DEBUG] Temp file written successfully, size: 50493 bytes
[DEBUG] Applied original permissions to temp file
[DEBUG] Renaming C:\Users\jmors\.claude.json.tmp.6052.1763116580889 to C:\Users\jmors\.claude.json
[DEBUG] File C:\Users\jmors\.claude.json written atomically
[DEBUG] Stream started - received first chunk
[DEBUG] Stream started - received first chunk
[DEBUG] Getting matching hook commands for SubagentStop with query: undefined
[DEBUG] Found 0 hook matchers in settings
[DEBUG] Matched 0 unique hooks for query "no match query" (0 before deduplication)
[DEBUG] Getting matching hook commands for SubagentStop with query: undefined
[DEBUG] Found 0 hook matchers in settings
[DEBUG] Matched 0 unique hooks for query "no match query" (0 before deduplication)
[DEBUG] LSP Diagnostics: getLSPDiagnosticAttachments called
[DEBUG] LSP Diagnostics: Checking registry - 0 pending
[DEBUG] LSP Diagnostics: Returning 0 diagnostic set(s) for delivery
[DEBUG] Hooks: getAsyncHookResponseAttachments called
[DEBUG] Hooks: checkForNewResponses called
[DEBUG] Hooks: Found 0 total hooks in registry
[DEBUG] Hooks: checkForNewResponses returning 0 responses
[DEBUG] Getting matching hook commands for UserPromptSubmit with query: undefined
[DEBUG] Found 0 hook matchers in settings
[DEBUG] Matched 0 unique hooks for query "no match query" (0 before deduplication)
[DEBUG] FileHistory: Added snapshot for 81aa6d09-3cc7-4219-84a1-376629251cf5, tracking 0 files
[DEBUG] Writing to temp file: C:\Users\jmors\.claude.json.tmp.6052.1763116620473
[DEBUG] Preserving file permissions: 100666
[DEBUG] Temp file written successfully, size: 50538 bytes
[DEBUG] Applied original permissions to temp file
[DEBUG] Renaming C:\Users\jmors\.claude.json.tmp.6052.1763116620473 to C:\Users\jmors\.claude.json
[DEBUG] File C:\Users\jmors\.claude.json written atomically
[DEBUG] Skills and commands included in Skill tool:
[DEBUG] Slash commands included in SlashCommand tool:
[DEBUG] Stream started - received first chunk
[DEBUG] Stream started - received first chunk
[DEBUG] Stream started - received first chunk
[ERROR] Error: Error: Language not supported while highlighting code, falling back to markdown: 
    at $5 (B:/~BUN/root/claude.exe:1226:4395)
    at <anonymous> (B:/~BUN/root/claude.exe:1226:4117)
    at map (native:1:11)
    at M4 (B:/~BUN/root/claude.exe:1226:4109)
    at vXI (B:/~BUN/root/claude.exe:1590:6668)
    at IE (B:/~BUN/root/claude.exe:101:19663)
    at H2 (B:/~BUN/root/claude.exe:103:42806)
    at rw (B:/~BUN/root/claude.exe:103:38344)
    at cf (B:/~BUN/root/claude.exe:103:38272)
    at Q7 (B:/~BUN/root/claude.exe:103:38126)
[DEBUG] executePreToolHooks called for tool: Bash
[DEBUG] executePreToolHooks called for tool: Glob
[DEBUG] Getting matching hook commands for PreToolUse with query: Bash
[DEBUG] Found 0 hook matchers in settings
[DEBUG] Matched 0 unique hooks for query "Bash" (0 before deduplication)
[DEBUG] Getting matching hook commands for PreToolUse with query: Glob
[DEBUG] Found 0 hook matchers in settings
[DEBUG] Matched 0 unique hooks for query "Glob" (0 before deduplication)
[DEBUG] Session environment not yet supported on Windows
[DEBUG] Getting matching hook commands for PostToolUse with query: Bash
[DEBUG] Found 0 hook matchers in settings
[DEBUG] Matched 0 unique hooks for query "Bash" (0 before deduplication)
[DEBUG] Getting matching hook commands for PostToolUse with query: Glob
[DEBUG] Found 0 hook matchers in settings
[DEBUG] Matched 0 unique hooks for query "Glob" (0 before deduplication)
[DEBUG] executePreToolHooks called for tool: Bash
[DEBUG] Getting matching hook commands for PreToolUse with query: Bash
[DEBUG] Found 0 hook matchers in settings
[DEBUG] Matched 0 unique hooks for query "Bash" (0 before deduplication)
[DEBUG] Stream started - received first chunk
[DEBUG] Stream started - received first chunk
[DEBUG] Permission suggestions for Bash: [
  {
    "type": "addRules",
    "rules": [
      {
        "toolName": "Bash",
        "ruleContent": "dir:*"
      }
    ],
    "behavior": "allow",
    "destination": "localSettings"
  }
]
[DEBUG] Getting matching hook commands for Notification with query: permission_prompt
[DEBUG] Found 0 hook matchers in settings
[DEBUG] Matched 0 unique hooks for query "permission_prompt" (0 before deduplication)
[DEBUG] Persisting permission update: addRules to source 'localSettings'
[DEBUG] Persisting 1 allow rule(s) to localSettings
[DEBUG] Writing to temp file: C:\Users\jmors\.claude\.claude\settings.local.json.tmp.6052.1763116651231
[DEBUG] Temp file written successfully, size: 99 bytes
[DEBUG] Renaming C:\Users\jmors\.claude\.claude\settings.local.json.tmp.6052.1763116651231 to C:\Users\jmors\.claude\.claude\settings.local.json
[DEBUG] File C:\Users\jmors\.claude\.claude\settings.local.json written atomically
[DEBUG] Applying permission update: Adding 1 allow rule(s) to destination 'localSettings': ["Bash(dir:*)"]
[DEBUG] AutoUpdaterWrapper: Installation type: native
[DEBUG] Session environment not yet supported on Windows
[DEBUG] Checking for native installer update to version 2.0.37
[DEBUG] Version 2.0.37 already installed, updating symlink
[DEBUG] Successfully updated to version 2.0.37
[DEBUG] Getting matching hook commands for PostToolUse with query: Bash
[DEBUG] Found 0 hook matchers in settings
[DEBUG] Matched 0 unique hooks for query "Bash" (0 before deduplication)
[DEBUG] LSP Diagnostics: getLSPDiagnosticAttachments called
[DEBUG] LSP Diagnostics: Checking registry - 0 pending
[DEBUG] LSP Diagnostics: Returning 0 diagnostic set(s) for delivery
[DEBUG] Hooks: getAsyncHookResponseAttachments called
[DEBUG] Hooks: checkForNewResponses called
[DEBUG] Hooks: Found 0 total hooks in registry
[DEBUG] Hooks: checkForNewResponses returning 0 responses
[DEBUG] Skills and commands included in Skill tool:
[DEBUG] Slash commands included in SlashCommand tool:
[DEBUG] Stream started - received first chunk
[DEBUG] Stream started - received first chunk
[DEBUG] executePreToolHooks called for tool: Bash
[DEBUG] executePreToolHooks called for tool: Glob
[DEBUG] Getting matching hook commands for PreToolUse with query: Bash
[DEBUG] Found 0 hook matchers in settings
[DEBUG] Matched 0 unique hooks for query "Bash" (0 before deduplication)
[DEBUG] Getting matching hook commands for PreToolUse with query: Glob
[DEBUG] Found 0 hook matchers in settings
[DEBUG] Matched 0 unique hooks for query "Glob" (0 before deduplication)
[DEBUG] Session environment not yet supported on Windows
[DEBUG] Getting matching hook commands for PostToolUse with query: Bash
[DEBUG] Found 0 hook matchers in settings
[DEBUG] Matched 0 unique hooks for query "Bash" (0 before deduplication)
[DEBUG] Getting matching hook commands for PostToolUse with query: Glob
[DEBUG] Found 0 hook matchers in settings
[DEBUG] Matched 0 unique hooks for query "Glob" (0 before deduplication)
[DEBUG] LSP Diagnostics: getLSPDiagnosticAttachments called
[DEBUG] LSP Diagnostics: Checking registry - 0 pending
[DEBUG] LSP Diagnostics: Returning 0 diagnostic set(s) for delivery
[DEBUG] Hooks: getAsyncHookResponseAttachments called
[DEBUG] Hooks: checkForNewResponses called
[DEBUG] Hooks: Found 0 total hooks in registry
[DEBUG] Hooks: checkForNewResponses returning 0 responses
[DEBUG] Stream started - received first chunk
[DEBUG] Skills and commands included in Skill tool:
[DEBUG] Slash commands included in SlashCommand tool:
[DEBUG] Stream started - received first chunk
[DEBUG] executePreToolHooks called for tool: Read
[DEBUG] Getting matching hook commands for PreToolUse with query: Read
[DEBUG] Found 0 hook matchers in settings
[DEBUG] Matched 0 unique hooks for query "Read" (0 before deduplication)
[DEBUG] Getting matching hook commands for PostToolUse with query: Read
[DEBUG] Found 0 hook matchers in settings
[DEBUG] Matched 0 unique hooks for query "Read" (0 before deduplication)
[DEBUG] executePreToolHooks called for tool: Read
[DEBUG] Getting matching hook commands for PreToolUse with query: Read
[DEBUG] Found 0 hook matchers in settings
[DEBUG] Matched 0 unique hooks for query "Read" (0 before deduplication)
[DEBUG] Stream started - received first chunk
[DEBUG] Getting matching hook commands for PostToolUse with query: Read
[DEBUG] Found 0 hook matchers in settings
[DEBUG] Matched 0 unique hooks for query "Read" (0 before deduplication)
[DEBUG] executePreToolHooks called for tool: Bash
[DEBUG] Getting matching hook commands for PreToolUse with query: Bash
[DEBUG] Found 0 hook matchers in settings
[DEBUG] Matched 0 unique hooks for query "Bash" (0 before deduplication)
[DEBUG] Stream started - received first chunk
[DEBUG] Stream started - received first chunk
[DEBUG] Permission suggestions for Bash: [
  {
    "type": "addRules",
    "rules": [
      {
        "toolName": "Bash",
        "ruleContent": "cat:*"
      }
    ],
    "behavior": "allow",
    "destination": "localSettings"
  }
]
[DEBUG] Getting matching hook commands for Notification with query: permission_prompt
[DEBUG] Found 0 hook matchers in settings
[DEBUG] Matched 0 unique hooks for query "permission_prompt" (0 before deduplication)
[DEBUG] Persisting permission update: addRules to source 'localSettings'
[DEBUG] Persisting 1 allow rule(s) to localSettings
[DEBUG] Writing to temp file: C:\Users\jmors\.claude\.claude\settings.local.json.tmp.6052.1763116682674
[DEBUG] Preserving file permissions: 100666
[DEBUG] Temp file written successfully, size: 120 bytes
[DEBUG] Applied original permissions to temp file
[DEBUG] Renaming C:\Users\jmors\.claude\.claude\settings.local.json.tmp.6052.1763116682674 to C:\Users\jmors\.claude\.claude\settings.local.json
[DEBUG] File C:\Users\jmors\.claude\.claude\settings.local.json written atomically
[DEBUG] Applying permission update: Adding 1 allow rule(s) to destination 'localSettings': ["Bash(cat:*)"]
[DEBUG] AutoUpdaterWrapper: Installation type: native
[DEBUG] Session environment not yet supported on Windows
[DEBUG] Checking for native installer update to version 2.0.37
[DEBUG] Version 2.0.37 already installed, updating symlink
[DEBUG] Successfully updated to version 2.0.37
[DEBUG] Getting matching hook commands for PostToolUse with query: Bash
[DEBUG] Found 0 hook matchers in settings
[DEBUG] Matched 0 unique hooks for query "Bash" (0 before deduplication)
[DEBUG] LSP Diagnostics: getLSPDiagnosticAttachments called
[DEBUG] LSP Diagnostics: Checking registry - 0 pending
[DEBUG] LSP Diagnostics: Returning 0 diagnostic set(s) for delivery
[DEBUG] Hooks: getAsyncHookResponseAttachments called
[DEBUG] Hooks: checkForNewResponses called
[DEBUG] Hooks: Found 0 total hooks in registry
[DEBUG] Hooks: checkForNewResponses returning 0 responses
[DEBUG] Skills and commands included in Skill tool:
[DEBUG] Slash commands included in SlashCommand tool:
[DEBUG] Stream started - received first chunk
[DEBUG] Stream started - received first chunk
[DEBUG] Stream started - received first chunk
[DEBUG] executePreToolHooks called for tool: Bash
[DEBUG] executePreToolHooks called for tool: Glob
[DEBUG] Getting matching hook commands for PreToolUse with query: Bash
[DEBUG] Found 0 hook matchers in settings
[DEBUG] Matched 0 unique hooks for query "Bash" (0 before deduplication)
[DEBUG] Getting matching hook commands for PreToolUse with query: Glob
[DEBUG] Found 0 hook matchers in settings
[DEBUG] Matched 0 unique hooks for query "Glob" (0 before deduplication)
[DEBUG] Session environment not yet supported on Windows
[DEBUG] Getting matching hook commands for PostToolUse with query: Bash
[DEBUG] Found 0 hook matchers in settings
[DEBUG] Matched 0 unique hooks for query "Bash" (0 before deduplication)
[DEBUG] Getting matching hook commands for PostToolUse with query: Glob
[DEBUG] Found 0 hook matchers in settings
[DEBUG] Matched 0 unique hooks for query "Glob" (0 before deduplication)
[DEBUG] LSP Diagnostics: getLSPDiagnosticAttachments called
[DEBUG] LSP Diagnostics: Checking registry - 0 pending
[DEBUG] LSP Diagnostics: Returning 0 diagnostic set(s) for delivery
[DEBUG] Hooks: getAsyncHookResponseAttachments called
[DEBUG] Hooks: checkForNewResponses called
[DEBUG] Hooks: Found 0 total hooks in registry
[DEBUG] Hooks: checkForNewResponses returning 0 responses
[DEBUG] Stream started - received first chunk
[DEBUG] Skills and commands included in Skill tool:
[DEBUG] Slash commands included in SlashCommand tool:
[DEBUG] Stream started - received first chunk
[DEBUG] executePreToolHooks called for tool: Read
[DEBUG] Getting matching hook commands for PreToolUse with query: Read
[DEBUG] Found 0 hook matchers in settings
[DEBUG] Matched 0 unique hooks for query "Read" (0 before deduplication)
[DEBUG] Getting matching hook commands for PostToolUse with query: Read
[DEBUG] Found 0 hook matchers in settings
[DEBUG] Matched 0 unique hooks for query "Read" (0 before deduplication)
[DEBUG] LSP Diagnostics: getLSPDiagnosticAttachments called
[DEBUG] LSP Diagnostics: Checking registry - 0 pending
[DEBUG] LSP Diagnostics: Returning 0 diagnostic set(s) for delivery
[DEBUG] Hooks: getAsyncHookResponseAttachments called
[DEBUG] Hooks: checkForNewResponses called
[DEBUG] Hooks: Found 0 total hooks in registry
[DEBUG] Hooks: checkForNewResponses returning 0 responses
[DEBUG] Skills and commands included in Skill tool:
[DEBUG] Slash commands included in SlashCommand tool:
[DEBUG] Stream started - received first chunk
[DEBUG] Stream started - received first chunk
[ERROR] Error: Error: Language not supported while highlighting code, falling back to markdown: 
    at $5 (B:/~BUN/root/claude.exe:1226:4395)
    at <anonymous> (B:/~BUN/root/claude.exe:1226:4117)
    at map (native:1:11)
    at M4 (B:/~BUN/root/claude.exe:1226:4109)
    at vXI (B:/~BUN/root/claude.exe:1590:6668)
    at IE (B:/~BUN/root/claude.exe:101:19663)
    at H2 (B:/~BUN/root/claude.exe:103:42806)
    at rw (B:/~BUN/root/claude.exe:103:38344)
    at cf (B:/~BUN/root/claude.exe:103:38272)
    at Q7 (B:/~BUN/root/claude.exe:103:38126)
[DEBUG] executePreToolHooks called for tool: AskUserQuestion
[DEBUG] Getting matching hook commands for PreToolUse with query: AskUserQuestion
[DEBUG] Found 0 hook matchers in settings
[DEBUG] Matched 0 unique hooks for query "AskUserQuestion" (0 before deduplication)
[DEBUG] Getting matching hook commands for Notification with query: permission_prompt
[DEBUG] Found 0 hook matchers in settings
[DEBUG] Matched 0 unique hooks for query "permission_prompt" (0 before deduplication)
[DEBUG] AutoUpdaterWrapper: Installation type: native
[DEBUG] Getting matching hook commands for PostToolUse with query: AskUserQuestion
[DEBUG] Found 0 hook matchers in settings
[DEBUG] Matched 0 unique hooks for query "AskUserQuestion" (0 before deduplication)
[DEBUG] LSP Diagnostics: getLSPDiagnosticAttachments called
[DEBUG] LSP Diagnostics: Checking registry - 0 pending
[DEBUG] LSP Diagnostics: Returning 0 diagnostic set(s) for delivery
[DEBUG] Hooks: getAsyncHookResponseAttachments called
[DEBUG] Hooks: checkForNewResponses called
[DEBUG] Hooks: Found 0 total hooks in registry
[DEBUG] Hooks: checkForNewResponses returning 0 responses
[DEBUG] Skills and commands included in Skill tool:
[DEBUG] Slash commands included in SlashCommand tool:
[DEBUG] Checking for native installer update to version 2.0.37
[DEBUG] Version 2.0.37 already installed, updating symlink
[DEBUG] Successfully updated to version 2.0.37
[DEBUG] Stream started - received first chunk
[DEBUG] executePreToolHooks called for tool: Read
[DEBUG] Getting matching hook commands for PreToolUse with query: Read
[DEBUG] Found 0 hook matchers in settings
[DEBUG] Matched 0 unique hooks for query "Read" (0 before deduplication)
[DEBUG] Getting matching hook commands for PostToolUse with query: Read
[DEBUG] Found 0 hook matchers in settings
[DEBUG] Matched 0 unique hooks for query "Read" (0 before deduplication)
[DEBUG] executePreToolHooks called for tool: Bash
[DEBUG] Getting matching hook commands for PreToolUse with query: Bash
[DEBUG] Found 0 hook matchers in settings
[DEBUG] Matched 0 unique hooks for query "Bash" (0 before deduplication)
[DEBUG] Stream started - received first chunk
[DEBUG] Stream started - received first chunk
[DEBUG] Permission suggestions for Bash: [
  {
    "type": "addRules",
    "rules": [
      {
        "toolName": "Bash",
        "ruleContent": "head:*"
      }
    ],
    "behavior": "allow",
    "destination": "localSettings"
  }
]
[DEBUG] AutoUpdaterWrapper: Installation type: native
[DEBUG] Session environment not yet supported on Windows
[DEBUG] Checking for native installer update to version 2.0.37
[DEBUG] Version 2.0.37 already installed, updating symlink
[DEBUG] Successfully updated to version 2.0.37
[DEBUG] Getting matching hook commands for PostToolUse with query: Bash
[DEBUG] Found 0 hook matchers in settings
[DEBUG] Matched 0 unique hooks for query "Bash" (0 before deduplication)
[DEBUG] executePreToolHooks called for tool: Bash
[DEBUG] Getting matching hook commands for PreToolUse with query: Bash
[DEBUG] Found 0 hook matchers in settings
[DEBUG] Matched 0 unique hooks for query "Bash" (0 before deduplication)
[DEBUG] Session environment not yet supported on Windows
[DEBUG] Stream started - received first chunk
[DEBUG] Getting matching hook commands for PostToolUse with query: Bash
[DEBUG] Found 0 hook matchers in settings
[DEBUG] Matched 0 unique hooks for query "Bash" (0 before deduplication)
[DEBUG] LSP Diagnostics: getLSPDiagnosticAttachments called
[DEBUG] LSP Diagnostics: Checking registry - 0 pending
[DEBUG] LSP Diagnostics: Returning 0 diagnostic set(s) for delivery
[DEBUG] Hooks: getAsyncHookResponseAttachments called
[DEBUG] Hooks: checkForNewResponses called
[DEBUG] Hooks: Found 0 total hooks in registry
[DEBUG] Hooks: checkForNewResponses returning 0 responses
[DEBUG] Stream started - received first chunk
[DEBUG] Skills and commands included in Skill tool:
[DEBUG] Slash commands included in SlashCommand tool:
[DEBUG] Stream started - received first chunk
[DEBUG] Stream started - received first chunk
[DEBUG] Writing to temp file: C:\Users\jmors\.claude.json.tmp.6052.1763116769054
[DEBUG] Preserving file permissions: 100666
[DEBUG] Temp file written successfully, size: 50538 bytes
[DEBUG] Applied original permissions to temp file
[DEBUG] Renaming C:\Users\jmors\.claude.json.tmp.6052.1763116769054 to C:\Users\jmors\.claude.json
[DEBUG] File C:\Users\jmors\.claude.json written atomically
[DEBUG] executePreToolHooks called for tool: Bash
[DEBUG] Getting matching hook commands for PreToolUse with query: Bash
[DEBUG] Found 0 hook matchers in settings
[DEBUG] Matched 0 unique hooks for query "Bash" (0 before deduplication)
[DEBUG] Session environment not yet supported on Windows
[DEBUG] executePreToolHooks called for tool: Read
[DEBUG] Getting matching hook commands for PreToolUse with query: Read
[DEBUG] Found 0 hook matchers in settings
[DEBUG] Matched 0 unique hooks for query "Read" (0 before deduplication)
[DEBUG] Getting matching hook commands for PostToolUse with query: Bash
[DEBUG] Found 0 hook matchers in settings
[DEBUG] Matched 0 unique hooks for query "Bash" (0 before deduplication)
[DEBUG] Stream started - received first chunk
[DEBUG] Getting matching hook commands for PostToolUse with query: Read
[DEBUG] Found 0 hook matchers in settings
[DEBUG] Matched 0 unique hooks for query "Read" (0 before deduplication)
[DEBUG] LSP Diagnostics: getLSPDiagnosticAttachments called
[DEBUG] LSP Diagnostics: Checking registry - 0 pending
[DEBUG] LSP Diagnostics: Returning 0 diagnostic set(s) for delivery
[DEBUG] Hooks: getAsyncHookResponseAttachments called
[DEBUG] Hooks: checkForNewResponses called
[DEBUG] Hooks: Found 0 total hooks in registry
[DEBUG] Hooks: checkForNewResponses returning 0 responses
[DEBUG] Skills and commands included in Skill tool:
[DEBUG] Slash commands included in SlashCommand tool:
[DEBUG] Stream started - received first chunk
[DEBUG] Stream started - received first chunk
[DEBUG] Writing to temp file: C:\Users\jmors\.claude.json.tmp.6052.1763116793562
[DEBUG] Preserving file permissions: 100666
[DEBUG] Temp file written successfully, size: 50563 bytes
[DEBUG] Applied original permissions to temp file
[DEBUG] Renaming C:\Users\jmors\.claude.json.tmp.6052.1763116793562 to C:\Users\jmors\.claude.json
[DEBUG] File C:\Users\jmors\.claude.json written atomically
[DEBUG] Getting matching hook commands for Stop with query: undefined
[DEBUG] Found 0 hook matchers in settings
[DEBUG] Matched 0 unique hooks for query "no match query" (0 before deduplication)
[DEBUG] Skills and commands included in Skill tool:
[DEBUG] Slash commands included in SlashCommand tool:
[DEBUG] Stream started - received first chunk
[ERROR] Error: Error: Language not supported while highlighting code, falling back to markdown: 
    at $5 (B:/~BUN/root/claude.exe:1226:4395)
    at <anonymous> (B:/~BUN/root/claude.exe:1226:4117)
    at map (native:1:11)
    at M4 (B:/~BUN/root/claude.exe:1226:4109)
    at vXI (B:/~BUN/root/claude.exe:1590:6668)
    at IE (B:/~BUN/root/claude.exe:101:19663)
    at H2 (B:/~BUN/root/claude.exe:103:42806)
    at rw (B:/~BUN/root/claude.exe:103:38344)
    at cf (B:/~BUN/root/claude.exe:103:38272)
    at Q7 (B:/~BUN/root/claude.exe:103:38126)
[DEBUG] executePreToolHooks called for tool: Write
[DEBUG] Getting matching hook commands for PreToolUse with query: Write
[DEBUG] Found 0 hook matchers in settings
[DEBUG] Matched 0 unique hooks for query "Write" (0 before deduplication)
[DEBUG] Permission suggestions for Write: [
  {
    "type": "setMode",
    "mode": "acceptEdits",
    "destination": "session"
  }
]
[DEBUG] AutoUpdaterWrapper: Installation type: native
[DEBUG] FileHistory: Tracked file modification for C:\Users\jmors\.claude\BUG_REPORT_SKILLS_NOT_LOADING_WINDOWS.md
[DEBUG] Checking for native installer update to version 2.0.37
[DEBUG] Version 2.0.37 already installed, updating symlink
[DEBUG] Successfully updated to version 2.0.37
[DEBUG] Writing to temp file: C:\Users\jmors\.claude\BUG_REPORT_SKILLS_NOT_LOADING_WINDOWS.md.tmp.6052.1763116835226
[DEBUG] Temp file written successfully, size: 4987 bytes
[DEBUG] Renaming C:\Users\jmors\.claude\BUG_REPORT_SKILLS_NOT_LOADING_WINDOWS.md.tmp.6052.1763116835226 to C:\Users\jmors\.claude\BUG_REPORT_SKILLS_NOT_LOADING_WINDOWS.md
[DEBUG] File C:\Users\jmors\.claude\BUG_REPORT_SKILLS_NOT_LOADING_WINDOWS.md written atomically
[DEBUG] Getting matching hook commands for PostToolUse with query: Write
[DEBUG] Found 0 hook matchers in settings
[DEBUG] Matched 0 unique hooks for query "Write" (0 before deduplication)
[DEBUG] LSP Diagnostics: getLSPDiagnosticAttachments called
[DEBUG] LSP Diagnostics: Checking registry - 0 pending
[DEBUG] LSP Diagnostics: Returning 0 diagnostic set(s) for delivery
[DEBUG] Hooks: getAsyncHookResponseAttachments called
[DEBUG] Hooks: checkForNewResponses called
[DEBUG] Hooks: Found 0 total hooks in registry
[DEBUG] Hooks: checkForNewResponses returning 0 responses
[DEBUG] Skills and commands included in Skill tool:
[DEBUG] Slash commands included in SlashCommand tool:
[DEBUG] Stream started - received first chunk
[DEBUG] Writing to temp file: C:\Users\jmors\.claude.json.tmp.6052.1763116844762
[DEBUG] Preserving file permissions: 100666
[DEBUG] Temp file written successfully, size: 50563 bytes
[DEBUG] Applied original permissions to temp file
[DEBUG] Renaming C:\Users\jmors\.claude.json.tmp.6052.1763116844762 to C:\Users\jmors\.claude.json
[DEBUG] File C:\Users\jmors\.claude.json written atomically
[DEBUG] Getting matching hook commands for Stop with query: undefined
[DEBUG] Found 0 hook matchers in settings
[DEBUG] Matched 0 unique hooks for query "no match query" (0 before deduplication)
[DEBUG] Writing to temp file: C:\Users\jmors\.claude.json.tmp.6052.1763116844818
[DEBUG] Preserving file permissions: 100666
[DEBUG] Temp file written successfully, size: 50563 bytes
[DEBUG] Applied original permissions to temp file
[DEBUG] Renaming C:\Users\jmors\.claude.json.tmp.6052.1763116844818 to C:\Users\jmors\.claude.json
[DEBUG] File C:\Users\jmors\.claude.json written atomically
[DEBUG] Getting matching hook commands for Notification with query: idle_prompt
[DEBUG] Found 0 hook matchers in settings
[DEBUG] Matched 0 unique hooks for query "idle_prompt" (0 before deduplication)

Steps to Reproduce

Minimal Reproduction

Install Claude Code 2.0.37 on Windows (any Windows 10/11 version)

Create a test skill directory:

``cmd mkdir %USERPROFILE%\.claude\skills\test-skill``

Create a minimal SKILL.md file:

Create %USERPROFILE%\.claude\skills\test-skill\SKILL.md with:

```yaml
---
name: test-skill
description: A minimal test skill to verify skill loading works
---

# Test Skill
This is a test skill.
```

Restart Claude Code (close and reopen the terminal/application)

Verify skills are not loaded:

Enable debug logging and check the debug log:

``cmd type %USERPROFILE%\.claude\debug\*.txt | findstr "Loaded.*unique skills"``

Expected output: Loaded 1 unique skills (user: 1, ...)

Actual output: Loaded 0 unique skills (managed: 0, user: 0, project: 0, duplicates removed: 0)

Attempt to invoke the skill:

In Claude Code session, try to invoke the skill programmatically or via the Skill tool with skill name test-skill

Expected: Skill loads and executes

Actual: Error messages:

Error: unknown skill
skill not registered with the system

Verify the skill file exists and is readable:

``cmd type %USERPROFILE%\.claude\skills\test-skill\SKILL.md``

Should display the file contents correctly.

Full Reproduction with Official Skills

Install Claude Code 2.0.37 on Windows

Install official Anthropic skills marketplace:

``claude plugins install anthropic-agent-skills``

Or verify it's already installed:

``cmd dir %USERPROFILE%\.claude\plugins\marketplaces\anthropic-agent-skills\document-skills\pdf\SKILL.md``

Restart Claude Code

Check debug logs:

``cmd type %USERPROFILE%\.claude\debug\*.txt | findstr /C:"Total plugin skills loaded"``

Expected: Total plugin skills loaded: 15 (or similar non-zero number)

Actual: Total plugin skills loaded: 0

Attempt to use the pdf skill:

Try invoking the pdf skill (which should be available from the marketplace)

Expected: Skill loads

Actual: Error: unknown skill and skill not registered with the system

Key Debug Log Lines to Check

After any Claude Code session, examine the latest debug file in %USERPROFILE%\.claude\debug\:

type %USERPROFILE%\.claude\debug\*.txt | findstr /C:"Loading skills from" /C:"Loaded.*unique skills" /C:"Total plugin skills"

What you'll see on broken Windows installation:

[DEBUG] Loading skills from directories: managed=C:\ProgramData\ClaudeCode\.claude\skills, user=C:\Users\[USER]\.claude\skills, project=C:\Users\[USER]\.claude\.claude\skills
[DEBUG] Total plugin skills loaded: 0
[DEBUG] Loaded 0 unique skills (managed: 0, user: 0, project: 0, duplicates removed: 0)

What you should see on working installation:

[DEBUG] Loading skills from directories: managed=C:\ProgramData\ClaudeCode\.claude\skills, user=C:\Users\[USER]\.claude\skills, project=C:\Users\[USER]\.claude\.claude\skills
[DEBUG] Total plugin skills loaded: 15
[DEBUG] Loaded 48 unique skills (managed: 0, user: 47, project: 0, duplicates removed: 14)

Environment Verification Commands

echo Windows Version:
ver

echo Claude Code Version:
claude --version

echo Skills directory exists:
dir %USERPROFILE%\.claude\skills

echo Skills in directory:
dir /s /b %USERPROFILE%\.claude\skills\SKILL.md

echo Plugin skills exist:
dir /s /b %USERPROFILE%\.claude\plugins\marketplaces\anthropic-agent-skills\*\SKILL.md

Additional Context

Claude Model

Sonnet (default)

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

2.0.37

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

Warp

Additional Information

_No response_

View original on GitHub ↗

This issue has 2 comments on GitHub. Read the full discussion on GitHub ↗

[BUG]

Preflight Checklist

What's Wrong?

Bug Report: Skills Not Loading on Windows

Summary

Environment

Problem Description

Evidence from Debug Logs

Skills Are Properly Formatted

Example 1: skills/Research/Analytics/python-paper-implementation/SKILL.md

Example 2: Official Anthropic skill plugins/marketplaces/anthropic-agent-skills/document-skills/pdf/SKILL.md

File System Verification

Root Cause Hypothesis

Expected Behavior

Actual Behavior

Impact

Reproduction Steps

Additional Context

Workaround

What Should Happen?

Error Messages/Logs

Steps to Reproduce

Steps to Reproduce

Minimal Reproduction

Full Reproduction with Official Skills

Key Debug Log Lines to Check

Environment Verification Commands

Additional Context

Claude Model

Is this a regression?

Last Working Version

Claude Code Version

Platform

Operating System

Terminal/Shell

Additional Information

Example 1: `skills/Research/Analytics/python-paper-implementation/SKILL.md`

Example 2: Official Anthropic skill `plugins/marketplaces/anthropic-agent-skills/document-skills/pdf/SKILL.md`