API Apocalypse: What Happens When Every API Breaks and Your Agent Has to Evolve

APIs break. They change response formats without warning, rate-limit you into oblivion, and go offline at 3 AM. Every developer has written code that worked Monday and failed Friday because a third-party endpoint decided temperature should now be nested inside weather.temp_celsius. The usual fix: a human notices, updates the parser, deploys, and hopes nothing else broke. What if an agent could fix itself? We ran an experiment to find out. The Setup: API Apocalypse We created a controlled chaos environment — three mock weather API sources that progressively degrade over 30 seconds: Time Source A (JSON) Source B (XML) Source C (CSV) 0–6s Normal Normal Normal 6s Format change Normal Normal 12s Changed Format change Normal 18s Changed Changed Format change 24s Rate limited (429) Changed Changed 28s Rate limited Offline (503) Changed Two agents compete in the same environment: Rotifer Agent: 6 genes (2 per API source), auto-failover based on runtime fitness Baseline Agent: 3 fixed parsers,