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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 v2.1.221 3 Aug 2026

MCP SDK handles input_required over multiple round trips

You'll notice

Useful3 Signal0

MCP Notable not in their notes

MCP tools that ask for extra input are now answered automatically, up to ten back-and-forth rounds.

inputRequired.maxRoundsinputRequired.autoFulfillallowInputRequired

What

Tool and request results marked resultType: "input_required" are now satisfied automatically by the client, which fulfils the server's input requests through registered handlers and re-issues the call.

Details

Defaults are autoFulfill on and a cap of 10 rounds.
Exceeding the cap fails with a message naming inputRequired.maxRounds.
Error text points at the alternatives, allowInputRequired: true or enabling inputRequired.autoFulfill.
Claude Code never passes an inputRequired option, so the defaults always apply.

Evidence

rounds (inputRequired.maxRounds)

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

See this entry in the whole of v2.1.221 →