Problem

DefaultResourceLoader.reload() from @mariozechner/pi-coding-agent blocks the Node.js event loop for 12-15 seconds on every agent run on Windows/NTFS. This is caused by extensive use of synchronous filesystem operations:

• readdirSync, statSync, readFileSync, existsSync — 21+ occurrences in resource-loader.js, 15+ in discovery-CVL9-KJt.js
• These scan directories recursively across multiple locations on every reload() call

Directories scanned on every reload()

• ~/.openclaw/extensions, ~/.openclaw/skills, ~/.openclaw/prompts, ~/.openclaw/themes
• <workspace>/.openclaw/extensions, <workspace>/.openclaw/skills, etc.
• ~/.agents/skills
• Ancestor directory scanning via collectAncestorAgentsSkillDirs()
• All npm package resolution paths

Impact

• Event loop blocked: eventLoopDelayP99Ms=12297ms, eventLoopUtilization=1.0
• Tool call timeouts: GatewayTransportError: gateway timeout after 10000ms
• Duplicate Telegram messages: Preview cleanup queued behind blocked event loop
• Slow WebSocket responses: chat.history 200-3800ms, node.list 248-2258ms
• Subagent spawns: Every subagent also pays the 12s overhead

Log evidence

prep stages: totalMs=14809 stages=workspace-sandbox:1ms,skills:1ms,core-plugin-tools:2199ms,bootstrap-context:17ms,bundle-tools:790ms,system-prompt:4ms,session-resource-loader:11787ms@14799ms,agent-session:2ms,stream-setup:8ms

session-resource-loader alone accounts for 80% of prep time.

Environment

• OpenClaw: 2026.5.7 (eeef486)
• OS: Windows 10 (26200), NTFS
• Node: v24.13.0
• .openclaw directory: 14,560 files
• Workspace skills: 64 files (after archiving 21 unused)

Proposed fixes

1. Cache resource discovery results between runs — only rescan when file mtimes change
2. Convert sync fs to async with fs.promises.* (though the reload must complete before the run starts, so this alone would not reduce total time — but it would stop blocking the event loop)
3. Expose skip flags — DefaultResourceLoader already supports noExtensions, noSkills, noThemes, noPromptTemplates, noContextFiles constructor options, but OpenClaw does not expose these via config. Adding config options like agents.defaults.skipResourceTypes: ["themes", "prompts"] would let users opt out of unused resource types.