From 4111f593689b9bc8c0b7936fbd8b0e23628855ae Mon Sep 17 00:00:00 2001
From: Ed_ <edwardgz@gmail.com>
Date: Sat, 20 Jun 2026 11:40:21 -0400
Subject: [PATCH] TIER-2 READ TIER1_REVIEW: execute mixed-approach per Tier 1
 directive

Tier 1's decision (NOT Tier 2's blanket Option A):
1. Add audit heuristic for narrow + structured error carrier (return ErrorInfo,
   or dict[error] = True if caller checks the flag). Handles L332, L355, L994.
2. Migrate 3 empty-default sites to Result[T] (L394 set_provider, L716+L723
   _execute_tool_calls_concurrently). Per styleguide:528-531, empty-default
   is NOT a drain.
3. Verify L994 caller. If they check err_item[error], heuristic. If not, migrate.

Reasoning: tier 2 conflated 'return ErrorInfo' and 'return empty default' as
both legitimate, but the styleguide distinguishes them. Empty default = sliming.

Phase 10+ continues with per-site decision: is the body returning structured
error (heuristic candidate) or empty default (migrate)?