What happened

Running opencode run can crash with a TypeError when the task tool is invoked without subagent_type (e.g. category-only calls, or continuation calls that only pass session_id).

Stack trace observed:

TypeError: undefined is not an object (evaluating 'str.replace')
  at titlecase (packages/opencode/src/util/locale.ts:3:12)
  at task (packages/opencode/src/cli/cmd/run.ts:170:24)
  at loop (packages/opencode/src/cli/cmd/run.ts:455:15)

The crash happens because packages/opencode/src/cli/cmd/run.ts assumes info.input.subagent_type is always present:

const agent = Locale.titlecase(info.input.subagent_type)

When it is undefined, Locale.titlecase() throws.

Repro

1. Run opencode run and cause the model to call the task tool without subagent_type (common valid cases):
   • task(category="...", ...) (category-only)
   • task(session_id="...", ...) (continuation-only)
2. Observe the CLI crash above.

Expected

opencode run should never crash; it should render a sensible fallback label when subagent_type is missing (e.g. use category, or default to "Task").

Suggested fix

Guard subagent_type in the run formatter, e.g.:

• const agentRaw = info.input.subagent_type ?? info.input.category ?? "task";
• pass a safe string to Locale.titlecase()

Environment

• opencode: 1.1.53 (local dev wrapper)
• oh-my-opencode: 3.4.0
• macOS (darwin)