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Sweep 08 Oct 2026 · 18:53Z Build v2.1.295 516 read Stable v2.1.286 Latest v2.1.295 Next v2.1.295 Feeds RSS JSON llms.txt llms-full.txt Unofficial
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Claude Code v2.1.290 ·

MCP error scrubbing now stops on overly long or deeply encoded text

Claude Code's scrubbing of MCP server details from error text now has limits and fails with an error when text is too long or too deeply encoded

You'll notice Improvements
JSON All of v2.1.290
You'll noticeTier: how much it should matter to you
1Useful: my rating, 1 to 5
1Signal: worth watching, 1 to 5
MCPArea: what it touches
ImprovementsKind: in v2.1.290,
ImprovementsSection of the release

Unclear The actual limits, and whether these new errors can appear on your screen, are not settled.

What

MCP servers are outside tools you connect to Claude Code. When one of them reports an error, Claude Code removes the server's own settings (its URL, arguments, headers and environment values) from the error text before showing it. Part of that work is undoing layers of encoding so hidden copies of those values are found too.

That step now has a cap on how many layers it undoes and on how long the text may get. Past those limits it stops with one of these errors instead of quietly using its last attempt:

  • MCP error text or config too long or too deeply encoded
  • MCP error text too long once decoded

It also now reads URLs in a way that no longer hides URL errors.

Why

It is meant to stop secrets in an MCP server's settings from slipping through an error message by being encoded several times over.

How sure we are
Something disagreesSomething we can check disagrees with this entry, or the writer said they could not settle it.
The writer flagged doubtThe actual limits, and whether these new errors can appear on your screen, are not settled.

See this entry in the whole of v2.1.290 →

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