Long agent sessions blow past any context window eventually. Compaction is the mechanism that compresses old turns into summaries before the context overflows. Done well, the agent keeps running indefinitely. Done poorly, the agent forgets the original goal halfway through. The cure for poor compaction is goal pinning plus a memory module that persists structured state across the compression boundary.
Engineering notes from the Digitorn team. No marketing, no launch announcements, no "10 prompts that will change your life". Just the things we write that we'd want to read.