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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

Claude Code v2.1.265 ·

MCP tool-allowlist subset checking (pc) rewritten around a safe array/object reader

The internal check for MCP server tool-allowlist subsets was rewritten to safely handle hostile or malformed data

Under the hood Internal Changes
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Internal ChangesKind: in v2.1.265,
Internal ChangesSection of the release
What

The internal logic that checks whether a server's allowed-tools set is a subset of another set (used to enforce MCP tool restrictions) was rewritten around new helper functions that canonicalize and safely read array and object values. The new helpers bound how large a list can be and catch errors from objects with throwing property getters, guarding against malformed or adversarial input.

Why

This hardens the tool-allowlist comparison against malformed or maliciously-crafted data, so a bad MCP server response can't crash or bypass the allowlist check.

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