[FEATURE] Support MCP Calls on sub agents

Preflight Checklist

• [x] I have searched existing requests and this feature hasn't been requested yet
• [x] This is a single feature request (not multiple features)

Problem Statement

I'm trying to use the Linear MCP Server but invoking it on sub agents is failing, it can only work on the main thread.

Conclusion: The Claude Code Task/subagent system currently does not initialize MCP server connections for custom agents, regardless of how mcpServers is configured. This is a platform limitation — the mcp-remote config is correct in principle, but the runtime doesn't act on it.

Tested it with Context7 too:

The Context7 tools do exist as deferred tools in the main session. Let me verify they work by loading and calling them directly.

Proposed Solution

Not sure what's needed.

Alternative Solutions

_No response_

Priority

Critical - Blocking my work

Feature Category

MCP server integration

Use Case Example

Create a subagent (.claude/agents/mcp-worker.md)

Instruct it to use Context7 MCP Server, but could be other.

Tools calls will fail.

Additional Context

_No response_