A rendering job came through my diagram API last month: a flowchart for a deployment runbook, one node labeled build (x86) . Unquoted parentheses inside square brackets are a classic Mermaid parse trap, and this diagram tripped it. What surprised me wasn't the failure — it was that my API answered 200 OK with 40 KB of PNG and the job marked done. I opened the image. It was a tidy little box that said "Syntax error in text". Mermaid doesn't throw on bad syntax during render; it draws the pars...