Session title generation bypasses plugin hooks

Description

Session title generation bypasses plugin hooks entirely. The title agent's LLM call sends the raw first user message straight to the model — it never goes through plugin.trigger("experimental.chat.messages.transform", ...), unlike the main chat completion.

This means any plugin that redacts/anonymizes outgoing content (secrets, PII, etc.) has no way to intercept the title-generation request. The main chat message gets scrubbed correctly; the title request for the exact same message does not.

Suggested fix:
route title()'s outgoing messages through plugin.trigger("experimental.chat.messages.transform", ...) before the llm.stream() call, or add a dedicated hook for it.

Workaround in the meantime:
{"agent": {"title": {"disable": true}}} stops the call entirely (loses auto-generated titles).

Plugins

@rehydra/opencode v0.13.0 (used to surface the gap — content-transform plugins in general are affected, not specific to this one)

OpenCode version

1.18.20

Steps to reproduce

1. Install a plugin that redacts outgoing message content via experimental.chat.messages.transform
2. Start a new session, send a first message containing a secret
3. Inspect actual outbound HTTP requests (MITM proxy or request tracer)
4. See two LLM calls from the same input: main chat completion is scrubbed correctly; the title-generation call (agent=title, small=true) contains the raw, unscrubbed secret

Screenshot and/or share link

No response

Operating System

macOS 26.5.2

Terminal

iTerm2