Today I Learned — Daily learnings
After overriding InvokeHarness's model from Claude to OpenAI gpt-oss, the gpt-oss model inherited the history and claimed to be Claude. Don't trust a model's self-report to tell which one is running.
Mounting ~/.aws into a Docker container fails to resolve SSO tokens. Extract temporary credentials from boto3 and pass them as environment variables instead.
Strands Agents SDK's agent() is a blocking call. Calling it inside an async def FastAPI endpoint blocks the event loop and hangs the request. Switching to def fixes it.
Strands Agents SDK Graph with cycles (feedback loops) fails build() auto-detection with ValueError. Use set_entry_point to specify the starting node explicitly.
Strands Agents SDK Graph's result.execution_time returns 0ms. Per-node execution_time is correct, so calculate the total yourself.
In Strands Agents SDK Swarm, agents that hand off via handoff_to_agent have no text block in their result. The final text output comes from the last agent that didn't hand off.
AWS Agent Registry CLI uses skillMd (dict with inlineContent) while REST API uses skillMarkdown (string). descriptorType is AGENT_SKILLS, not SKILL.
AWS Agent Registry MCP records require reverse-DNS name format, 100-char description limit, and explicit schemaVersion. The error message doesn't tell you which field is wrong.
During Aurora PostgreSQL Blue/Green Switchover, the docs mention AdminShutdown as the expected error. Through RDS Proxy, you get SSL connection has been closed unexpectedly instead. Important for error handling design.
Adding a managed node group to an EKS Auto Mode cluster fails with NodeCreationFailure (cni plugin not initialized). Installing vpc-cni, kube-proxy, and coredns addons resolves the issue.