Codex gate (the key one): the persistedSnippetByTid fallback read S.session.tool_calls,
but loadSession() keeps the messages=0 session object (tool_calls []), and the
real messages=1 summary arrives only as the sessionToolCalls argument to
_syncToolCallsForLoadedMessages() — never copied onto S.session. So the fallback
source was empty on exactly the cold-load path it repairs. Persist
sessionToolCalls onto S.session.tool_calls in _syncToolCallsForLoadedMessages
(covering _ensureMessagesLoaded, older-message paging, and full-history loaders)
so renderMessages builds a populated persistedSnippetByTid. + guard test.
Codex gate: the third derived-push site (Anthropic tool_use content-array branch,
ui.js) still read resultsByTid[tid]||'' without the persisted fallback, so
Anthropic-format sessions could still cold-reload with an empty tool body. Add
the persistedSnippetByTid fallback there too; now all derived result-snippet
reads (OpenAI top-level, Anthropic tool_use, partial) chain to the durable
persisted snippet. Added a guard test asserting EVERY derived resultSnippet read
includes the fallback.
In the transparent stream, terminal output and patch diffs intermittently
vanished after a cold/paginated reload. A settled tool row renders its body from
`snippet`, but the raw-assistant-envelope 'derived' rebuild only joined the
result by tool id via resultsByTid (role:tool messages); when that join missed
(id mismatch, recovery-rebuilt turn) the snippet was empty, and #4622's live
enrichment only helps when S.toolCalls still matches (empty on cold load).
Build a persistedSnippetByTid lookup from the durable session.tool_calls compact
summary (which carries a bounded result snippet per tid) and use it as a
fallback in all three derived-push sites, so the persisted record is the
reliable source and the live join becomes a fast-path, not the only path that
shows the body. Part of #4925.
