August 22, 2026 · Joy
Send the delta, not the whole terminal history
The default move after a long agent session is to paste everything back in: the command, the logs, the stack traces, the last twenty turns, “just in case.”
That feels safe. It is usually waste.
The model does not need the whole terminal history. It needs what changed — the delta — plus enough surrounding state to act.
Why full history hurts
- Tokens — you pay to re-read work that already ran.
- Attention — the useful line sits under a pile of noise.
- The machine — duplicated context is how multi-agent setups jam a laptop.
Bounded context is not “make the prompt shorter for style.” It is sending a view of execution: resumable reads, not a dump of scrollback.
What JoyMux does
JoyMux keeps execution sessions durable, then lets you hand the agent a bounded context view.
Crash recovery and deltas are the same idea: do not reconstruct the world from a dead buffer. Read from evidence. Send what is new.
Token fire drops as a consequence. In founder testing that showed about 10× improvement — said honestly, as a secondary result. The headline is still: the agent sees the delta, not the whole terminal.
A practical check
Before the next prompt, ask: what did the agent not already see? Send that. Keep the rest in the execution layer, where it can be replayed if you missed it.