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Sweep 10 Nov 2026 · 02:18Z Build v2.1.322 539 read Stable v2.1.311 Latest v2.1.322 Next v2.1.322 Feeds RSS JSON llms.txt llms-full.txt Unofficial
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Claude Code v2.1.321 ·

MCP tool calls can report download progress

MCP tool calls can send download progress, tools can be marked as delivering files, and the UI handles download updates

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Unclear What Claude Code does differently with a tool marked as delivering files is not shown.

What

MCP servers are outside programs that give Claude Code extra tools. Before, the progress messages they send, called mcp_progress, carried only a progress count and a total. Claude Code now supports MCP servers that deliver files:

  • mcp_progress events can carry a download payload, and the interface handles these separately.
  • A new step runs before each MCP tool call. It receives the client, the tool, the arguments, the parent message and the context.
  • MCP tools whose _meta field has anthropic/delivers set to true are marked listedAsDeliveringFiles.
  • Cloud URLs are now tracked for each tool (cloudUrlByTool).
  • The state for connector instruction blocks was reworked.

Why

This lays the groundwork for showing download progress while an MCP tool delivers a file. In practice, an MCP server can now say that its tools deliver files and report how a download is going.

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