Slash-command and skill prompts can enter the title-generation path as internal XML breadcrumbs. The async title request previously treated that transport metadata as user prose, so a generated ai-title could persist raw command tags and override the normal session title.
This routes title sources and generated title output through a shared sanitizer, preserving user-visible command names and arguments while dropping unrelated internal XML metadata. Desktop fallback title rendering now applies the same cleanup so existing transcripts with bad ai-title entries recover on read.
Constraint: Session titles can be produced by both desktop server logic and the SDK generate_session_title control request.
Rejected: Only clean desktop session display | leaves CLI and remote title generation able to persist bad titles again
Confidence: high
Scope-risk: moderate
Directive: Keep generated-title input and persisted-title readback on the shared sanitizer; do not add a title path that reads command XML directly.
Tested: bun test src/utils/__tests__/sessionTitle.test.ts src/utils/__tests__/sessionTitleText.test.ts
Tested: bun run check:server
Tested: bun run check:desktop
Tested: bun run verify (7 passed, 1 failed on existing aggregate agent-utils coverage baseline)
Not-tested: live model title-generation smoke
Session titles need to appear immediately, but the async AI title pass can return fenced or escaped JSON fragments. Keep the first-message title path fast, preserve optimistic client titles during background refresh, and only accept structured title responses that parse cleanly.
Constraint: Desktop sessions should stop showing Untitled/New Session after the first user turn.
Rejected: Accept short raw model output as a fallback | malformed JSON fragments are short enough to leak into the UI.
Confidence: high
Scope-risk: moderate
Directive: Do not loosen generated title parsing without regression coverage for fenced, escaped, and truncated JSON responses.
Tested: bun test src/server/__tests__/title-service.test.ts
Tested: bun run check:server
Tested: cd desktop && bun run test -- --run src/stores/chatStore.test.ts src/stores/sessionStore.test.ts src/pages/EmptySession.test.tsx
Tested: agent-browser smoke on http://127.0.0.1:1420/ confirmed sidebar and tab titles update without JSON fragments.
