2,000-line transparent agent core Stellar completes 106 tasks in 17 min for $2.40
anandesh-sharma · reddit · 2026-09-11
Frustrated with agent stacks that are hard to inspect, debug, and reshape, the author built Stellar: a fully hackable Python agent core with under 2,000 readable lines and explicit contracts for models, tools, hooks, events, agents, and runs — the execution loop is right there in the code.
To test whether "small" also means "capable," the author ran it against Harness-Bench: one recorded run completed all 106 offline tasks end to end, twelve in parallel, in 17 minutes, costing about $2.40 in tokens at list price.
The open question: does a small transparent core beat a big framework as an agent foundation, or does it just push complexity into prompts, tools, and glue code? Repo is open source at definableai/stellar.
Related event: Dev Builds Stellar, a 2000-Line Minimal Agent Core(2 posts)→
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