{"version":"2.1.296","anchor":"mcp-tools-can-upload-local-files-via-file-input-arguments-t","canonical_anchor":"mcp-tools-can-upload-local-files-via-file-input-arguments-t","heading":"MCP tools can receive files uploaded from your computer","tier":"notice","area":"MCP","scope":"individual","heads_up":false,"url":"https:\/\/changelogs.core-directive.com\/v\/2.1.296\/e\/mcp-tools-can-upload-local-files-via-file-input-arguments-t","release_url":"https:\/\/changelogs.core-directive.com\/v\/2.1.296","markdown":"### MCP tools can receive files uploaded from your computer\n\nMCP tools that declare file inputs can now take local file paths, which Claude Code uploads and replaces with references\n\n**Unclear.** Which MCP servers pass the policy check that allows file attachments is not stated.\n\n**What**\n\nMCP servers are outside programs that give Claude extra tools. A tool whose description declares `anthropic\/fileInputs` can now be given paths to files on your computer. Claude Code then:\n\n- computes a fingerprint of each file\n\n- asks the server for permission through its `authorize_upload` tool\n\n- uploads the files to the addresses the server returns\n\n- replaces the file paths with the references the server returns\n\nThis applies only to servers that pass a policy check, and it sits behind a setting Claude Code receives from Anthropic's servers. When it fails, Claude Code shows messages such as \"The files could not be attached.\" or \"This organization's policy does not allow attaching files here.\"\n\n**Why**\n\nThis gives MCP servers a new way to receive your local files. If you see one of these attachment messages, the upload was blocked or failed and the tool did not get the file.\n\n- Flag `tengu_walnut_tiller`: Not enough to say (read for one account on one subscription tier against v2.1.296; this account: no value returned, anonymous baseline: no value returned, compiled default: off) These values were read against a different version of Claude Code, so treat them as the nearest reading available instead of one taken on this release.\n- Area: MCP\n- Names: `anthropic\/fileInputs`\n- Tier: You'll notice\n- Useful: 5\/5\n- Signal: 4\/5\n- Scope: individual\n- Heads-up: no"}