Error on ExecutableResult::success call in entity_field_values tool

Problem/Motivation

I am testing out the tools in the Tool Belt module for use in an MCP server (MCP Server Drupal module). When I try to call the entity_field_values tool with a valid entity artifact for the entity argument, I get the following PHP error:

Tool execution failed: Drupal\tool\ExecutableResult::success(): Argument #1 ($message) must be of type Drupal\Core\StringTranslation\TranslatableMarkup, string given, called in /tool_belt/modules/tool_belt_content/src/Plugin/tool/Tool/EntityFieldValues.php on line 116

Note that this only occurs if and when the tool call results in one or more fields being denied access. In that scenario, the $message variable sent to the success() method is actually a concatenation of two t() calls, which is likely why the error is hit.

Steps to reproduce

Because this tool requires an entity artifact for the argument, I don't know the best way to reproduce, but the tool can be executed from the Tool explorer in a scenario where there will be fields that are denied access, or as I noted, when the tool is invoked via an MCP server where there will be fields that are denied access.

Proposed resolution

Instead of trying to concatenate two distinct t() calls, there can be an ExecutableResult::success() call when there are field that are defined access and a call when there are not, with the relevant $message string and placeolders used. I have attached a patch with a local fix.

Remaining tasks

User interface changes

API changes

Data model changes