Anthropic publishes Claude Code post‑mortem and issues fixes
devApr 23, 202640170
Anthropic published a post-mortem saying Claude Code had three quality issues, and the company shipped fixes in v2.1.116+ while resetting usage limits for affected users. One root cause was a new system prompt that required keeping text between tool calls to 25 words or fewer and final responses to 100 words or less, which cut Claude Code's score on Anthropic's internal evaluations by 3 percent. Anthropic adjusted prompts and other behaviors in v2.1.116+, reopened normal access, and emphasized restoring reliability for developers WHO use Claude Code to triage issues and support security and engineering workflows.
Key Highlights
Anthropic fixed three Claude Code quality issues in release v2.1.116+.
A system prompt forced ≤25 words between tool calls and ≤100 words final responses.
Claude Code's performance on Anthropic's evals fell 3 percent from that change.