{"version":"2.1.290","anchor":"mcp-serve-tool-calls-run-in-a-per-call-session-scope-git-d","canonical_anchor":"mcp-serve-tool-calls-run-in-a-per-call-session-scope-git-d","heading":"Claude Code as an MCP server runs each tool call in its own context","tier":"notice","area":"MCP","scope":"individual","heads_up":false,"url":"https:\/\/changelogs.core-directive.com\/v\/2.1.290\/e\/mcp-serve-tool-calls-run-in-a-per-call-session-scope-git-d","release_url":"https:\/\/changelogs.core-directive.com\/v\/2.1.290","markdown":"### Claude Code as an MCP server runs each tool call in its own context\n\nWhen serving tools over MCP, each tool call now runs in its own session context, and a slow workspace diff returns a structured error\n\n**Unclear.** What difference running each call in its own context makes for users is not clear.\n\n**What**\n\nMCP is a protocol that lets programs share tools. When Claude Code acts as an MCP server, so another program calls its tools, each tool call now runs in its own separate session context instead of the shared one.\n\nWhen a workspace diff, the list of file changes, takes too long, the call now returns a structured error with the code `workspace_diff_pending` rather than failing outright.\n\n**Why**\n\nThis is mostly internal rework. A program calling Claude Code's tools may now receive the `workspace_diff_pending` error code where it previously got a raw failure.\n\n- Area: MCP\n- Tier: You'll notice\n- Useful: 2\/5\n- Signal: 2\/5\n- Scope: individual\n- Heads-up: no"}