Best possible solution:

Land this focused alignment after maintainer review and exact-head validation, while keeping routing-mode drift and unrelated session-label reports separate.

Do we have a high-confidence way to reproduce the issue?

Yes. On current main, typing /new in Control UI reaches the local new slash-command case and sends chat.send with /new, while the New Chat button already uses createChatSession.

Is this the best way to solve the issue?

Yes. Reusing the existing dashboard createChatSession path for typed /new is the narrowest maintainable fix, and preserving /reset as an explicit Gateway reset keeps the documented boundary clear.

Acceptance criteria:

• node scripts/run-vitest.mjs run --config test/vitest/vitest.unit-ui.config.ts ui/src/ui/app-chat.test.ts ui/src/ui/chat/slash-commands.browser-import.test.ts
• node scripts/run-vitest.mjs run --config test/vitest/vitest.ui.config.ts ui/src/ui/app-render.helpers.node.test.ts
• pnpm exec oxfmt --check --threads=1 ui/src/ui/app-chat.ts ui/src/ui/app-chat.test.ts ui/src/ui/app.ts docs/web/control-ui.md docs/tools/slash-commands.md CHANGELOG.md
• pnpm check:changelog-attributions
• pnpm check:changed

What I checked:

• Protected PR context: GitHub API and provided context show this PR is open, authored by a MEMBER, labeled maintainer, and currently headed at 20f189a, so this cleanup workflow should not close it. (20f189a41eb2)
• Current-main typed /new behavior: On current main, the local slash-command new case still calls sendChatMessageNow(host, "/new", ...), which goes through the Gateway chat-send/reset route rather than dashboard session creation. (ui/src/ui/app-chat.ts:545, b8c0a1e9ff24)
• Existing dashboard session path: Current main already has createChatSession, which calls createSessionAndRefresh, switches to the returned session key, and preserves composer draft/attachments around the switch. (ui/src/ui/app-render.helpers.ts:608, b8c0a1e9ff24)
• Existing New Chat button wiring: The rendered Control UI New Chat action already calls createChatSession(state), matching the helper this PR routes typed /new through. (ui/src/ui/app-render.ts:2377, b8c0a1e9ff24)
• PR patch behavior: The PR patch excludes new from queued local slash commands, changes the new case to await host.onSlashAction("new-session"), and wires that action to createChatSessionInternal in the app host. (ui/src/ui/app-chat.ts:529, abaa6f90db46)
• Focused test coverage: The PR patch updates app-chat.test.ts to assert typed /new calls the fresh-session action without confirmation, does not queue behind an active run, and typed /reset still dispatches through chat.send. (ui/src/ui/app-chat.test.ts:469, abaa6f90db46)

Likely related people:

• vincentkoc: Merged related WebChat New Chat dashboard session create/switch work in fix(webchat): create dashboard sessions from New Chat #73725, which this PR extends to typed /new. (role: adjacent feature owner; confidence: high; commits: 983c634ec05b, 2e50f167cefa, 1912e309f7bc; files: ui/src/ui/app-render.helpers.ts, ui/src/ui/app-render.ts, ui/src/ui/app-chat.ts)
• steipete: Local blame shows the current split Control UI files and central typed slash-command path were introduced into the current checkout by the browser config facade refactor, and git history shows repeated adjacent WebChat/session maintenance. (role: recent maintainer; confidence: medium; commits: 68c99879e2bf, 19046e0cfcd6, 382785c6ced9; files: ui/src/ui/app-chat.ts, ui/src/ui/app-render.helpers.ts, ui/src/ui/app.ts)
• BunsDev: Provided review context connects this maintainer to recent current-main Control UI session continuity, active-run refresh, and slash-command discovery work beyond authorship of this PR. (role: recent maintainer; confidence: medium; commits: cb9d7884cca3, c34ed90822a9, d0c83777fb58; files: ui/src/ui/app-render.helpers.ts, ui/src/ui/app.ts, ui/src/ui/app-chat.ts)

Codex review notes: model gpt-5.5, reasoning high; reviewed against b8c0a1e9ff24.