Root Cause / Explanation
When API Access Control is enabled in a Salesforce org, MCP servers are able to authenticate successfully but any calls using query tools are blocked. This is a known compatibility gap between the two features.
Workaround :
NOTE : Disabling API Access Control or assigning "Use any API Client" permission allows MCP servers to function, but this removes a critical security control and is not recommended for production orgs with strict API access policies.
005321985

We use three kinds of cookies on our websites: required, functional, and advertising. You can choose whether functional and advertising cookies apply. Click on the different cookie categories to find out more about each category and to change the default settings.
Privacy Statement
Required cookies are necessary for basic website functionality. Some examples include: session cookies needed to transmit the website, authentication cookies, and security cookies.
Functional cookies enhance functions, performance, and services on the website. Some examples include: cookies used to analyze site traffic, cookies used for market research, and cookies used to display advertising that is not directed to a particular individual.
Advertising cookies track activity across websites in order to understand a viewer’s interests, and direct them specific marketing. Some examples include: cookies used for remarketing, or interest-based advertising.