## Problem/Motivation Creating or editing a small entity currently takes a tool call per step: create stub, set each field value, save (plus add revision when editing). For small entity types and small changes that is a lot of round trips, and each extra call is another chance for an AI invoker to lose the thread. ## Proposed resolution Add two one-shot tools to `tool_belt_content`: - **Create entity** (`tool_belt:entity_create`, Write): entity type ID, bundle, a `base_fields` map and a `fields` map (configurable fields); creates, validates and saves in one call and returns the saved entity and its ID. - **Update entity** (`tool_belt:entity_update`, Write): entity type ID and entity ID plus the same two maps. **Patch semantics:** only the fields passed are changed; everything else is left alone — no default values are filled in on update. Loads the latest revision, saves a new revision on revisionable entity types (revision user, creation time, and a log message defaulting to the changed field list, overridable via a `revision_log` input), and returns the updated entity and new revision ID. Shared behavior: - **Per-field access:** every provided field is checked with field-level `edit` access (the same check `field_set_value` runs), so field restrictions like node `status` requiring `administer nodes` — or content moderation forbidding direct `status` edits on moderated bundles — are enforced, with denied fields named in the failure. - **Validation before save:** entity violations fail the call with property paths and messages, so required-field and constraint errors come back as actionable feedback instead of an exception. - Unknown field names fail with the names listed; an update with no values fails rather than saving a no-op revision. - Input definitions are refined per entity type and bundle (reusing `EntityStub::getBaseFieldInputDefinition()` and a new `getBundleFieldsInputDefinition()`), and values are upcast through `FieldSetValue::upcastFieldValue()`, so the advertised schema matches the real fields. - Entity-level access mirrors the existing tools: create access for entity_create, update access for entity_update; the field-level checks run at execute time because they need the entity, the same split the entity form uses between route access and widget access. Deliberately no `save: FALSE` option: a non-saving create is exactly `entity_stub`, and a boolean that changes whether a Write tool writes muddies the operation semantics. The multi-call composition remains the path for incremental building. ## Remaining tasks - Review. - Kernel test coverage: patch semantics (untouched fields), per-field access denials, validation failures, revision creation and log message, latest-revision editing on moderated entities. - Consider honoring the bundle's default new-revision setting instead of always creating a revision on revisionable types. ## API changes None. Two new tool plugins, a public static `EntityStub::getBundleFieldsInputDefinition()` beside the existing base-field helper, and an `OneShotEntityFieldsTrait` with the field checks shared by the two tools. ## Data model changes None. ### AI usage (if applicable) - [x] **AI Assisted Issue:** This issue was generated with AI assistance, but was reviewed and refined by the creator. - [ ] **AI Assisted Code:** This code was mainly generated by a human, with AI autocompleting or parts AI generated, but under full human supervision. - [x] **AI Generated Code:** This code was mainly generated by an AI with human guidance, and reviewed, tested, and refined by a human. - [ ] **Vibe Coded:** This code was generated by an AI and has only been functionally tested.