We just shipped Mnemara 0.10.1. It fixes a bug that had been reproducing at a 30–50% rate in a specific workload, and the root cause is the kind of thing every async Python developer should have a mental bookmark for. So this post isn't really a release note — it's a debugging walkthrough.

The symptom

Calls to the write_memory MCP tool were intermittently failing with stream closed / CLIConnectionError, surfaced from the Anthropic Claude Agent SDK transport layer. The pattern was diagnostic in itself:

Failures only happened when the model invoked write_memory in rapid succession within a single turn.

Single calls were fine. Slow successive calls were fine.

Roughly 1 in 3 rapid calls failed. Sometimes 1 in 2.

Every reflex in our heads said "flaky network, add a retry." Every reflex in our heads was wrong.

The thing we refused to do

There's a strong temptation when you see "intermittent transport error" to wrap a try/except around it, retry on failure, and ship.…