mcp: fold Server.Session onto lp.ToolSession, bracket every isolate use - #3312
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Extract the Browser+Session+Notification+node Registry quartet, with its ordering-sensitive init/teardown and isolate enter/exit, into src/ToolSession.zig. mcp/Server.zig's sessions map now holds *lp.ToolSession directly; the session id lives only as the map key. Claude-Session: https://claude.ai/code/session_01M6WGk8wZSE28efFQkYT9SK
stdio kept the isolate permanently entered while HTTP parked it between requests, so a handler touching page JS without enterIsolate passed the stdio-mode tests and only failed under --port. Bracket unconditionally: stdio is the one-isolate case of the same discipline. The flag survives only as `multi_session`, which is what it always gated: the session tools need a transport that routes by id. Claude-Session: https://claude.ai/code/session_01M6WGk8wZSE28efFQkYT9SK
Two sessions on one thread, each entered only around its own use, with JS state proving the isolates are separate and a balanced park/enter/ deinit teardown. Pins what the C API relies on without Server in the loop. Claude-Session: https://claude.ai/code/session_01M6WGk8wZSE28efFQkYT9SK
Agent held the same Browser/Session/Notification/registry fields and teardown order as mcp/Server.zig, plus its own "enableConsoleCapture after every newSession" for /reset. ToolSession.restartSession() owns that now; init is written in terms of it. Claude-Session: https://claude.ai/code/session_01M6WGk8wZSE28efFQkYT9SK
This was referenced Aug 27, 2026
agent: fold the browser quartet onto lp.ToolSession
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Follow-up deferred from #3096: the c-api branch defines a
ToolSessioninline in lightpanda.zig for the Browser/Session/Notification/node Registry quartet, and mcp/Server.zig carries its own copy of the same init/teardown sequence. Landing the shared type on main first, so the c-api branch only drops its inline copy when it merges (same init/deinit/enterIsolate/exitIsolate API).src/ToolSession.zig: the quartet with its ordering-sensitive init/teardown and isolate enter/exit, re-exported aslp.ToolSession.Sessionwrapper.sessionsmaps straight to*lp.ToolSession, the id is only the map key.enterIsolatepassed the stdio-mode tests (56 of 57) and only failed under--port.park_isolatessurvives asmulti_session, which is what it actually gated: the session tools need a transport that routes byMcp-Session-Id.registry.register,frame.js) bracket the isolate;registercreates V8 handles.ToolSessiontest: two sessions on one thread, entered only around their own use, separate JS globals, balanced teardown. That is what c_api.zig relies on without Server in the loop.Not in this PR: Agent.zig, see #3313 (stacked on this one).
Verified: full suite (1282/1282);
lightpanda mcpover stdio with goto, evaluate, a refused session_new, clean exit.