1. Inconsistent config attribute pattern (providers.py:109)
  self.config: PolymarketInstrumentProviderConfig | None = config
  1. The class already inherits self._config from the parent. Adding self.config separately creates two attributes pointing to the same data, which is
  confusing. The code uses both self.config (line 123-124) and self._config (line 125).

  1. Recommendation: Use self._config consistently and add a property if needed for type narrowing.
  2. Redundant assertions (providers.py:142-144)
  assert self.config is not None
  assert self.config.event_slug_builder is not None
  2. These conditions are already guaranteed by the caller check on line 123. If validation is needed, Nautilus typically uses PyCondition class rather
  than assert.
  3. Broad exception handling (providers.py:178-182)
  except Exception as e:
      self._log.error(f"Failed to load event slug '{slug}': {e}")
  3. Catching bare Exception can mask unexpected errors. Consider catching more specific exceptions or at least logging the full traceback.
  4. Unused filters parameter (providers.py:131)
  The _load_from_event_slugs method accepts filters but never uses it. Either remove it or apply filters consistently.

  📝 Minor Suggestions

  1. The filters parameter could be used to pre-filter loaded instruments for consistency with other loading paths
  2. Consider logging at DEBUG level for individual slug loading instead of INFO, to reduce log noise when many slugs are processed
  3. The docstring for PolymarketInstrumentProviderConfig is good but could mention that load_all=True is required to trigger the builder (as noted in the
  example)

Test Coverage Analysis

  Current Coverage (6 tests)
  ┌─────────────────────────────────────────────────────────────┬────────────────────────────────────┐
  │                            Test                             │          Scenario Covered          │
  ├─────────────────────────────────────────────────────────────┼────────────────────────────────────┤
  │ test_load_all_async_uses_event_slug_builder_when_configured │ ✅ Basic happy path                │
  ├─────────────────────────────────────────────────────────────┼────────────────────────────────────┤
  │ test_event_slug_builder_takes_priority_over_gamma_markets   │ ✅ Priority over use_gamma_markets │
  ├─────────────────────────────────────────────────────────────┼────────────────────────────────────┤
  │ test_event_slug_builder_handles_multiple_slugs              │ ✅ Multiple slugs                  │
  ├─────────────────────────────────────────────────────────────┼────────────────────────────────────┤
  │ test_event_slug_builder_handles_empty_slug_list             │ ✅ Empty slug list                 │
  ├─────────────────────────────────────────────────────────────┼────────────────────────────────────┤
  │ test_event_slug_builder_continues_on_event_not_found        │ ✅ ValueError handling             │
  ├─────────────────────────────────────────────────────────────┼────────────────────────────────────┤
  │ test_event_slug_builder_skips_markets_without_condition_id  │ ✅ Missing conditionId             │
  └─────────────────────────────────────────────────────────────┴────────────────────────────────────┘
  
Missing Coverage
  ┌────────────────────────────────────────────────┬────────┬─────────────────────────────────────────────────┐
  │                      Gap                       │  Risk  │                    Code Path                    │
  ├────────────────────────────────────────────────┼────────┼─────────────────────────────────────────────────┤
  │ Invalid slug builder path (module not found)   │ High   │ resolve_path() raises ModuleNotFoundError       │
  ├────────────────────────────────────────────────┼────────┼─────────────────────────────────────────────────┤
  │ Invalid slug builder path (function not found) │ High   │ resolve_path() raises AttributeError            │
  ├────────────────────────────────────────────────┼────────┼─────────────────────────────────────────────────┤
  │ Slug builder raises exception                  │ Medium │ Exception in slug_builder() call                │
  ├────────────────────────────────────────────────┼────────┼─────────────────────────────────────────────────┤
  │ Generic exception during fetch                 │ Medium │ except Exception branch at line 180             │
  ├────────────────────────────────────────────────┼────────┼─────────────────────────────────────────────────┤
  │ Empty token_id in token_info                   │ Low    │ if not token_id branch at line 169-172          │
  ├────────────────────────────────────────────────┼────────┼─────────────────────────────────────────────────┤
  │ Factory integration                            │ Medium │ instrument_config attribute wiring in factories │
  ├────────────────────────────────────────────────┼────────┼─────────────────────────────────────────────────┤
  │ _log_warnings=False behavior                   │ Low    │ Warning suppression path                        │
  └────────────────────────────────────────────────┴────────┴─────────────────────────────────────────────────┘
  Verdict

  Coverage is decent for the happy paths but has gaps in error handling.

  The most critical missing tests are:

  1. Invalid path resolution - If a user misconfigures event_slug_builder with a typo like "mymodule:build_slugz", the code will crash with an unhandled
  exception. This should either be tested to confirm the behavior or the code should catch and handle it gracefully.
  2. Factory integration - The new instrument_config attribute replaces instrument_provider in the factories, but there are no tests verifying that the
  factory correctly passes this config to the provider.