Previously runBuiltinWithMessages deleted the session jsonl after each
run/continue call. This meant the createAgent retry mechanism (which
calls continue on frontmatter validation failure) would lose all
previous turn data — each continue started with an empty jsonl.
Now the session jsonl accumulates across run + continue calls, so the
final storeBuiltinDetail captures all turns. The jsonl file is left
behind for debugging; it's small and can be cleaned up on next startup.
Also add a workflow hint to the system prompt reminding the LLM to use
tools before outputting frontmatter, preventing premature text-only
responses on the first turn.
xingyue
a3fac708b6