Connector file uploads stream with progress, and blocked-connector messages explain failed checks

What

MCP connectors are outside services that give Claude extra tools, connected through the Model Context Protocol.

File transfers:

• Uploads no longer load the whole file into memory. They read it in pieces, check its fingerprint while sending, and stop if the file changes mid-send.
• Uploads report progress, and tool results can carry connectorFileLines, a list of files shown in a column under the message.
• New refusal codes: put_sealed_connector_not_allowed, put_tool_policy_not_allowed, put_blocked_by_anthropic and put_storage_not_connected. Refusals in the log now carry request IDs.
• Download failure text names a range of offered files, and tool calls with download offers forward progress.
• The cached tool list now expires after a set time rather than by a fixed age check.

Blocked connectors:

• When a plugin's server is blocked and the check against your organization's connector settings itself failed, the message says the server was not connected because the check failed, not that it is turned off. The hint says the plugin's entry for the server may be what the check cannot read. Otherwise it still says an organization admin can change this.
• These notices are tracked separately with a :check-failed marker.
• The upload policy_denied message is shorter.

Why

Large uploads use less memory, you can see them progress, and refusals say why. If a connector check fails, you are not sent to an admin for a setting that is not the problem.