Fable's "quiet personality" is actually a bug dropping 26% of its messages
Fable, the model used in Claude Code, has been widely seen as having a terse, low-chatter that just gets on with tasks. It turns out that's wrong: portions of its are being silently dropped on Anthropic's server before ever reaching the user's client. The issue is tracked on GitHub as anthropics/#74260, -loss.
Someone wrote a that scans local session files for the specific signature of these drops and ran it on two separate machines. Out of 23,295 Fable messages, 6,166 showed dropped text — 26% on both machines. The same scan across 73,000 messages from Opus 4.8, Opus 4.7, Sonnet 5, and Haiku 4.5 found zero instances, showing the problem is specific to Fable.
Because the script can only detect one missing block per message, the true drop rate is likely higher than 26%. Common symptoms include Fable asking whether you reviewed a list that was never shown, or popping up an empty box with no actual question text.
Key points
- Fable's perceived "quiet" is actually text loss, not a style choice.
- Tracked on GitHub as anthropics/#74260, -loss.
- 26% of 23,295 sampled Fable messages (6,166) had dropped text on both tested machines; 0 out of 73,000 messages from Opus/Sonnet/Haiku models showed the issue.
- The detection script can only catch one missing block per message, so the real loss rate may be higher than 26%.
- Symptoms include being asked about a list that was never shown, or an empty prompt with no question text.