Generative agents — three components from Park et al. 2023
memory stream
append-only log
[t=0] observation :: saw Isabella
[t=1] observation :: invited to party
[t=2] reflection :: I enjoy parties
[t=3] plan :: attend at 5pm
[t=4] action :: head to cafe
retrieval: recency + importance + relevance
top-k feeds prompts
reflection
higher-order beliefs
periodic trigger:
unprocessed importance > threshold
prompt: "given recent memories,
what is a higher-level insight?"
output: new reflection entries
re-ingested into the stream
without reflection: no belief formation
plan
day / hour / action
day: go to work, have dinner
hour: 9am cafe, 12pm lunch...
action: walk to cafe, order coffee
revision trigger:
observation contradicts plan
only affected segment re-plans
without plan: reactive noise
emergent behavior — Valentine's Day party
tick 0
agent-0 (Isabella) is seeded with: "host party at cafe, 5pm"
tick 0-2
Isabella invites neighbors; each invitation becomes an observation in their stream
tick 1-3
invited neighbors reflect -> belief "I am invited to a party" -> plan to attend
tick 2-4
invitees tell other neighbors; second-degree spread
tick 5
three components converge: 3-5 agents arrive at the cafe on time
single seed + three components = coordinated arrival without an orchestrator
documented failures: spatial norms (closed stores, single-person bathrooms)