## Problem/Motivation #3582971 added a logger to `ToolBase` as a promoted constructor property named `$logger`, typed `?LoggerChannelInterface`. Because `ToolBase::__construct()` is `final`, subclasses inject their own services by declaring a property and overriding `create()` — and the conventional name for a logger property in that pattern is exactly `$logger`. A subclass declaring the property with any _other_ type hits a compile-time PHP fatal (property redeclaration with a mismatched type). Confirmed casualties in tool_belt: `LogMessage` (`protected LoggerInterface $logger` + `create()` override — fatals on instantiation) and `WorkspaceCreateAndSwitch` (a latent fatal that would trigger when `tool_belt_workspace` is enabled). Git history scopes the exposure to the logger: it landed unreleased in 9b6ed79, while `$currentUser` and `$eventDispatcher` predate it by weeks — clashes there would have broken long ago. ## Ecosystem impact scan - **mcp_tools** (drupal.org master, 228 tools): zero impact. All 228 extend `McpToolsToolBase`, and neither the tools nor the intermediate base declare or touch `$logger`; the repo's `$logger` grep hits are unrelated services and unit tests. - **tool_belt** (44 tools): exactly the two known cases above. ## Considered and rejected: rename to $toolLogger A distinctive name (`$toolLogger`) would sidestep all collisions, but the scan showed the real blast radius is two small edits in our own companion module and nothing in the wild. `$logger` is the conventional name; pre-RC1 is the moment to claim it with a documented contract rather than cede it permanently. ## Proposed resolution - **`ToolBase`**: keep `$logger`, make it **required and non-nullable** (`protected LoggerChannelInterface $logger`). The nullability had no justification — `create()` always supplies `logger.channel.tool`, and the only containerless constructions found in the wild (mcp_tools' anonymous test tools) were already broken by July's required `$eventDispatcher`, so this adds no new breakage. The null guard in `execute()` is removed accordingly. - **Docblock contract**: subclasses redeclaring `$logger` must use the exact type `LoggerChannelInterface`, or PHP fatals on the mismatch. A subclass `create()` may assign its own channel over the parent's (as `WorkspaceCreateAndSwitch` does with `tool_belt_workspace`). - **tool_belt**: `LogMessage` drops its now-redundant property and `create()` override (the parent injects the same `tool` channel). `WorkspaceCreateAndSwitch` needs no change — its declaration is now an exact match. ## Verification Both files lint; `log_message` instantiates through the plugin manager; the site returns 200; all 185 tool kernel tests pass. ## AI usage (if applicable) - [x] **AI Assisted Issue:** This issue was generated with AI assistance, but was reviewed and refined by the creator. - [x] **AI Assisted Code:** This code was mainly generated by a human, with AI autocompleting or parts AI generated, but under full human supervision. - [ ] **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.