{"version":"2.1.307","anchor":"mcp-tool-calls-accept-extra-call-meta-chrome-file-upload-ge","canonical_anchor":"mcp-tool-calls-accept-extra-call-meta-chrome-file-upload-ge","heading":"Claude in Chrome file uploads gain a hosted path and a size limit","tier":"notice","area":"Chrome & Browser","scope":"individual","heads_up":true,"url":"https:\/\/changelogs.core-directive.com\/v\/2.1.307\/e\/mcp-tool-calls-accept-extra-call-meta-chrome-file-upload-ge","release_url":"https:\/\/changelogs.core-directive.com\/v\/2.1.307","markdown":"### Claude in Chrome file uploads gain a hosted path and a size limit\n\nClaude in Chrome's `file_upload` can now work through a hosted session with a byte limit, and MCP retries skip calls that may already have run\n\n**Unclear.** Which setups count as hosted is not stated, so it is unclear in which remote sessions file uploads are now allowed.\n\n**What**\n\nClaude in Chrome lets Claude control your Chrome browser, and its `file_upload` action uploads files to a web page. It used to be prepared only on your own machine. Now:\n\n- In hosted setups, the host can read the files instead of a local read, and the upload can pass a `maxTotalBytes` limit (from `FILE_UPLOAD_MAX_TOTAL_BYTES`) plus the hosted session.\n\n- A new `anthropic\/chromeUploadMaxBytes` setting caps the upload size.\n\n- `file_upload` now takes `paths` rather than `files`.\n\n- `file_upload` is refused only in a remote session with no host.\n\n- `file_upload` cannot run inside `browser_batch`, which bundles several browser actions. In that case the whole call is refused with the message 'file_upload cannot run inside browser_batch in this session', and nothing in the call runs.\n\nMCP servers are add-on programs that provide tools. MCP tool calls can now merge extra details, `mcpCallMeta`, into the request's `_meta` field, which is how the upload passes its information along.\n\nSeparately, when an MCP session expires and is reconnected, a tool call is retried only if it cannot have run already, the tool is safe to run at the same time as others, or the tool says repeating it is harmless (`idempotentHint`). Before, it was always retried.\n\n**Why**\n\nBrowser file uploads can work in hosted or remote setups within a size limit. Batched browser actions that include an upload now fail as a whole, and MCP tools that change things are not run twice after a reconnect.\n\n- Area: Chrome & Browser\n- Tier: You'll notice\n- Useful: 3\/5\n- Signal: 3\/5\n- Scope: individual\n- Heads-up: yes"}