fix(opencode): stop silent session title generation failures

[1837620622]

Issue for this PR

Closes#13710

Related (not closed by this PR):

• Session title generation silently fails with no fallback or logging #29734 — same silent-failure class; this PR covers the logging / survival side, not multi-provider fallback chains
• Auto-title generation silently fails when provider has no small model #25344 — model fallback/?? diagnosis; current getSmallModel already returns undefined on miss and falls back via ??
• Auto session title generation fails for opencode provider models (smallOptions missing provider config) #30662 — separate root cause (smallOptions missing opencode provider fields); not fixed here (small: true intentionally kept)

Type of change

• Bug fix

What does this PR do?

Session auto-naming (SessionPrompt.ensureTitle) can fail without useful logs, leaving sessions stuck as New session - <timestamp>.

Root causes on current dev:

Path	What happens	Why silent
Model resolution	getModel → typed ModelNotFoundError (Effect<Model, ModelNotFoundError>)	Call site used Effect.ignore → Fail discarded, zero log
Title LLM stream	llm.stream is Stream<LLMEvent, unknown> + Effect.orDie	Fail promoted to Die; Effect.ignore does not recover Die → fiber dies, no title
Residual defects	e.g. toModelMessagesEffect uses Effect.promise (rejections → Die)	No local handler; previously no fork-site log for Die

Minimal fix (no retry policy change; keep small: true):

Before	After
unguarded getModel / getSmallModel	Effect.option + tapError warning (typed Fail only; defects still propagate)
Effect.orDie on stream	Effect.catchAll → log + empty text (notcatchCause — avoids labeling Interrupt as LLM failure)
Effect.ignore on fork	Effect.catchCause → log residual Fail/Die; skip interrupt-only scope teardown
small: true	kept (preserves smallOptions, avoids #20269 / #20323)

Why this shape (Effect semantics)

• Effect.option is correct for getModel: only maps typed failure → Option.none, does not hide defects
• Stream errors are typed (unknown Fail channel) → catchAll is the right dual of removing orDie
• Fork catchCause is the safety net for toModelMessagesEffect defects and any remaining Die
• Interrupt-only causes are ignored at the fork so scope close does not spam warnings

Out of scope (on purpose)

• Multi-provider title fallback chain (Session title generation silently fails with no fallback or logging #29734 / closedfix(opencode): add fallback models for session title generation #29735)
• smallOptions opencode provider gaps (Auto session title generation fails for opencode provider models (smallOptions missing provider config) #30662)
• Changing title model selection policy

How did you verify your code works?

• Diff-reviewed against upstream ensureTitle on dev
• Failure chain confirmed: typed Fail + orDie Die + Effect.ignore ⇒ silent skip / no title
• Single-file change only (packages/opencode/src/session/prompt.ts)

Author

• GitHub: @1837620622 (传康Kk)
• Commit email: 35034498+1837620622@users.noreply.github.com (GitHub-verified noreply — required for Contributors graph)

Checklist

• Linked issue (Closes #13710)
• No unrelated changes
• No speculative retry / model-policy change

[1837620622]

Ready for review 🔍

Minimal, confirmed fix for intermittent silent auto-title failures reported in #13710.

Why safe:

• Only hardens error handling in ensureTitle — no model/cost policy change
• Keeps small: true (does not reintroduce variant/effort leakage)
• ~30 lines, no speculative retry loop
• Failures become logged instead of disappearing

Would appreciate a maintainer review when you have a moment. Happy to address nits quickly.

— 传康Kk (@1837620622)

[1837620622]

Friendly ping for maintainers 🙏

This is a minimal confirmed fix for #13710 (silent auto-title failures):

• Effect.option for model resolution
• Effect.catchAll instead of orDie on the title stream
• Effect.catchCause instead of ignore at the fork
• small: true kept (no cost/policy regression)

Single file, ~30 lines. Would love a review when you have a moment.

— @1837620622