While developing the TypeSafe AI provider, I began to create "Decision" operation types. First ai_decision was part of ai_provider_typesafe_ai, then I split into its own project, now we are working to integrate the functionality into AI core without a separate submodule. Throughout the evolution of that development this issue was discovered and a fix developed in https://git.drupalcode.org/project/ai/-/merge_requests/2046 among updates for other issues. This is 1 of a set of issues that will be solved with this MR. ## Problem/Motivation AI already has an `#[OperationType]` attribute for operation interfaces, but `Drupal\ai\Plugin\Discovery\OperationTypeDiscovery` only scans AI's own `src/OperationType` directory. A contrib or custom module cannot register an operation type just by declaring an attributed interface in its own `src/OperationType` directory. Instead it must use `hook_ai_operationtype_alter()` and repeat the ID, label and description already present on the attribute. The discovery parser also has a bug. `getInterfaceFromFile()` runs regular expressions over the whole file, comments included, so a docblock sentence such as "the interface directly extends OperationTypeInterface" can be taken as the declaration. The parser then returns `directly` as the interface name and misses the real interface below it. Other gaps: - The generated plugin `class` always assumes the `Drupal\ai` namespace. - Operation definitions are cached in `cache.discovery` (`ai_operation_types`), and nothing clears that entry when a module that adds operations is installed or uninstalled. - Two interfaces claiming the same operation ID would silently overwrite each other. ## Proposed resolution - Scan `src/OperationType` in every enabled module (`ModuleHandler::getModuleList()`). - Parse declarations with PHP tokens (`token_get_all()`), so comments and strings are ignored. - Record the providing module in a new `provider` key, and build the `class` from that module's namespace. - Throw `InvalidArgumentException` when two attributed interfaces declare the same operation ID. The message names both interfaces. - Delete the `ai_operation_types` entry from `cache.discovery` in `ai_modules_installed()` and a new `ai_modules_uninstalled()`. - The existing alter hooks (`ai_operationtype`, `ai_operation_types`) stay unchanged. Files: `src/Plugin/Discovery/OperationTypeDiscovery.php`, `ai.module`, `docs/developers/develop_third_party_module.md` ("Adding an optional operation type"). Tests: `tests/src/Kernel/OperationType/OperationTypeDiscoveryTest.php` covers: - install and uninstall with warm caches; - direct cache invalidation without a full rebuild; - duplicate IDs. Its fixture modules are `tests/modules/ai_operation_test` (whose docblock holds a misleading "interface … extends" sentence) and `tests/modules/ai_operation_duplicate_test`. ## Remaining tasks Review. ## User interface changes None. ## API changes - Attributed operation interfaces in any enabled module are discovered. - Operation type definitions gain a `provider` key. - A duplicate operation ID now throws `InvalidArgumentException` instead of the last one silently winning. The same definitions also carry an `input_validation_method` key the MR. That key belongs to the separate operation input-validation change, not to this issue. ## Data model changes None.