Allow Enterprise administrators to choose which MCPs for their organization are non-deferred

### Problem Statement

The MCP we have written for our enterprise customers would perform best if it was always loaded into context and not deferred to provide the user experience our customers are requesting.

### Proposed Solution

White tool_search_tool invoked our MCP _sometimes_ it would create a more consistent and predictable enterprise customer experience if Claude was always loading our MCP into context via an enterprise admin setting.

### Alternatives Considered

We've tried "hacking" the tool descriptions to cause tool_search_tool to find it more often but there is still a significant inconsistency where Claude decides it can answer the user's query with its pre-loaded default tools/model data.

### Area

Tool Discovery / Invocation

### Priority

Critical - Blocking my MCP server development

### Additional Context

The tool in question is an MCP version of the popular LibKey tool used by around 2,000 higher education, corporate, hospital and government libraries worldwide and is already integrated as an API into dozens of popular services related to full text academic content access (https://thirdiron.com/libkey-integration/). We have a number of Claude enterprise customers (Dartmouth, Northeastern University, etc.) who are requesting a turnkey solution of LibKey integration to make Claude more useful for their researchers engaging in scientific literature tasks. The MCP dynamically looks for article identifiers (DOI/PMIDs) and fetches the correct full text links. Depending on the way a researcher engages Claude for such scientific literature tasks it sometimes thinks it can do the web search and come back with some article citations and this is adequate. It is not. The links back to literature are designed for the general public (DOI.org links, publisher links, etc.). Whereas LibKey has knowledge of the specific authentication pathways, sourcing and availability that creates a personalized linking for the user based on their affiliation - greatly increasing the utility of using Claude for this purposes and minimizing clicks. Having this working in a turnkey way in Claude would be an excellent point for the Education sales team to use as well to show how through integration with our popular service, Claude links back to the local library collections for content access in a seamless way.