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DisclaimerUnofficial, and not affiliated with Anthropic. Nearly all of this is read straight out of what ships: npm bundles, captured prompts, published docs. Anthropic's own notes go in verbatim, marked as theirs. The rest is my reading, and every entry carries the strings behind it. If one looks wrong, vote it down and say why.

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Claude Code v2.1.248 27 Aug 2026

MCP timeout and two new connection batch-size settings

Use it now

Useful4 Signal3

MCP Notable

Two new env vars set how many MCP servers connect at once, local and remote.

MCP_SERVER_CONNECTION_BATCH_SIZEMCP_REMOTE_SERVER_CONNECTION_BATCH_SIZEMCP_TOOL_TIMEOUT

What

MCP_TOOL_TIMEOUT is now read through the central environment reader rather than parsed inline, and two new environment variables control how many MCP servers are connected at once: MCP_SERVER_CONNECTION_BATCH_SIZE (default 3) and MCP_REMOTE_SERVER_CONNECTION_BATCH_SIZE (default 20).

Details

The old inline parse required a value greater than zero; both tool-timeout helpers now share the one source.
Raise the remote batch size if you have many remote MCP servers and startup connection is slow.

Usage

MCP_REMOTE_SERVER_CONNECTION_BATCH_SIZE=40 claude

Evidence

MCP_REMOTE_SERVER_CONNECTION_BATCH_SIZE

Strings lifted out of the shipped bundle, so the claim above can be checked against them.

See this entry in the whole of v2.1.248 →