{"version":"2.1.116","anchor":"mcp-direct-tool-invocation-mcp-call","canonical_anchor":"mcp-direct-tool-invocation-mcp-call","heading":"MCP Direct Tool Invocation ( mcp_call )","tier":null,"area":null,"scope":null,"heads_up":null,"url":"https:\/\/changelogs.core-directive.com\/v\/2.1.116\/e\/mcp-direct-tool-invocation-mcp-call","release_url":"https:\/\/changelogs.core-directive.com\/v\/2.1.116","markdown":"### MCP Direct Tool Invocation (`mcp_call`)\n\n**What**\n\nNew `mcp_call` subtype for MCP requests that enables directly invoking MCP tools via the subprocess MCP client without requiring a model turn.\n\n**Details**\n\n- Accepts a fully-qualified MCP tool name (e.g., `mcp__server__tool_name`)\n- No permission check \u2014 the control channel is trusted\n- SDK-type MCP servers are rejected (they are caller-provided and should be invoked directly)\n- Handles URL elicitation for tools that require browser authentication\n- Result content passes through the same processing as model-turn MCP calls (large results may be truncated)\n\n**Evidence**\n\nMCP call handler (search for `\"mcp_call\"`) \u2014 `$K5` at line ~639274"}