Problem

When /model X is the first message after an idle/daily/suspended auto-reset, the slash-command path stores a session model override but leaves session_entry.was_auto_reset = True (it never passes through _handle_message_with_agent, where the flag was consumed). On the next regular message, the auto-reset cleanup block pops the freshly-stored model/reasoning override before the flag is consumed — so the switch is silently lost and resolution falls back to the config default, while the session DB still shows the switched model (a two-sources-of-truth divergence). (#48031)

Fix

Consume was_auto_reset at both sites:

1. gateway/run.py — capture the flag into a local and set the attribute False immediately at the top of the cleanup block, so the cleanup can't re-fire on a later message and wipe an override stored between turns. Downstream reads use the captured local.
2. gateway/slash_commands.py — the model path consumes the flag before storing the override, so a /model-first-after-auto-reset isn't wiped by the next message's cleanup.

Salvage / credit

Salvaged from #48062 by @x7peeps (authorship preserved).

Tests

tests/gateway/test_48031_model_switch_after_auto_reset.py — AST invariants pinning both consume sites (load-bearing: verified they FAIL when either consume is removed). Mirrors the AST-pin approach in test_35809_auto_reset_clean_context.py. Gateway session/reset suite: 16 passed.

Closes

Fixes #48031

Review status

The automated review batch timed out on the slow full tests/gateway/ run, so I verified manually with a scoped suite + targeted edge-case checks:

• (a) All downstream was_auto_reset reads in _handle_message_with_agent use the captured _was_auto_reset local (lines 8941, 8977); the only post-consume attribute writes are the False-assignments. No read depends on the flag still being True.
• (b) The pre-existing notice-block clear (~line 9036) is now redundant for the flag but still clears auto_reset_reason — harmless, not conflicting.
• (c) session_store.get_or_create_session() returns the same cached entry object for a given key (confirmed in gateway/session.py), so the slash-command path's consume mutates the same object the message handler later reads — the wipe is genuinely prevented.
• AST-invariant tests verified to FAIL when either consume is removed (load-bearing). Scoped gateway suite (session/reset/boundary/slash): 22 passed.