A Reddit user with too much time and a disassembler just exposed Anthropic's sneakiest cost increase yet. Using reverse engineering tools, they discovered that Anthropic silently changed Claude Code's cache expiry from 1 hour to just 5 minutes in early March. The result? Developer costs exploded by 5x overnight.

The smoking gun came from GitHub user who used Ghidra (the NSA's reverse engineering tool) to crack open Claude Code's closed-source binary. Deep in the code, they found the cache TTL (time-to-live) had been quietly switched from 3,600 seconds (1 hour) to just 300 seconds (5 minutes) on April 2nd.

The numbers are devastating. One developer tracked their usage before and after the change: cache busts went from 39 per day to 199 per day. Daily costs jumped from $6.28 to $15.54. Projected monthly impact: an extra $277. That's for one developer. Multiply across thousands of Claude Code users.

Here's what happened. Claude Code uses prompt caching to avoid reprocessing large codebases. When you're working on a project, Claude caches your files so it doesn't have to re-read everything on each request. But if you take a coffee break longer than 5 minutes, boom cache miss. Full reprocessing at full token rates.

The really sneaky part? Anthropic's documentation still says cache lasts "up to 1 hour." No announcement. No changelog. No warning. Existing users kept hitting cache misses and couldn't figure out why their bills were skyrocketing. Only someone reverse-engineering the binary would catch this.

When confronted, Anthropic claimed the quota drain wasn't caused by cache changes. Claude Code creator Boris Cherny diplomatically suggested that "prompt cache misses when using 1M token context window are expensive." Translation: working on large projects now costs a fortune.

Developers are fighting back. The community built a cache-fixing interceptor that forces the 1-hour TTL and stabilizes fingerprints. One user reported 98.4% cache hit rates across a 7.5-hour session. But users shouldn't need to hack their way around secret cost increases.

This is part of a broader pattern. Anthropic killed flat-rate Claude Code pricing for third-party tools, blocked OpenClaw users, and now secretly reduced cache efficiency. The message is clear: Anthropic wants developers using their tools their way at their prices. The era of Claude Code as a developer-friendly platform is ending.