fix(runtime): disable Playwright process signal handlers - #19
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Playwright defaults handleSIGINT/TERM to true, so after createSession it registers handlers that close Chromium and process.exit(130) on SIGINT, racing companion/MCP graceful shutdown. Own lifecycle like Playwright's embedded MCP launcher. Co-authored-by: esadrianno <esadrianno@gmail.com>
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Bug and impact
After the first
createSession, Playwright registers defaultSIGINT/SIGTERMhandlers (handleSIGINT/handleSIGTERMdefaulttrue). On Ctrl+C / SIGINT those handlers close Chromium and then callprocess.exit(130), racing companion/MCPcloseGracefully(runtime.shutdown→app.close→exit(0)). The HTTP server may not drain; exit is unclean; this compounds dead-browser / orphan races during daemon stop.Trigger: create at least one session (browser launched), then SIGINT the companion process.
Root cause
BrowserRuntime.launchBrowsercalledchromium.launch/webkit.launchwith onlyheadless, leaving Playwright process-signal ownership enabled. Playwright’s own embedded MCP launcher setshandleSIGINT: false/handleSIGTERM: falsefor the same reason.Fix
Pass
handleSIGINT: false,handleSIGTERM: false, andhandleSIGHUP: falseon both Chromium and WebKit launches so companion/MCP own lifecycle.Validation
pnpm --filter @webchain/runtime test— 27 passed (2 new launch-option assertions)pnpm --filter @webchain/runtime typecheck— greenDistinct from #10–#18
#12/#15 address companion/runtime shutdown ordering and
Promise.allSettled; neither disables Playwright’s process signal handlers (verified on those branches).