Claude Code now reads twice as much of your MCP tool description. The cut still exists.
By Lior AharonovFounder, 7IT Solutions ·
On Friday 9 October 2026, Claude Code 2.1.296 raised the default limit on MCP tool descriptions sent up front, and on MCP server instructions, from 2,048 to 4,096 characters. On npm it is the latest release, while the stable channel still points to 2.1.287.
Picture the line that tells the model when not to call your delete tool. If it sat past character 2,048, the model never saw it. Now it might, but only on the latest channel, and anything past 4,096 is still cut.
Measure every tool description and your server instructions today. Keep warnings and limits inside the first 2,048 characters, because users on the stable channel still run a release from before this change.
Write the description for the smallest window your users run. The bigger window is a bonus, never the plan.
Lior Aharonov · my takeSources
- Claude Code changelog, version 2.1.296 raw.githubusercontent.com
- npm registry: @anthropic-ai/claude-code release times and channels registry.npmjs.org
Researched with AI tools; every fact is checked against the linked sources.