A developer used Claude Code to build a semantic fuzzer for Obsidian Sync over 60 hours, progressing through three stages: initial unguided attempts that failed, guided prototyping that succeeded, and polishing that created more problems than solutions. The experience revealed Claude's limitations: it lacks persistent project memory, requires constant correction and guidance, and behaves like a knowledgeable but periodically memory-wiped junior engineer who needs explicit instruction to remain productive.