#Auto Compact

A3S Code can keep long conversations inside the model's context budget for you. Enable autoCompact and the runtime watches context usage; once it crosses autoCompactThreshold, older turns are compacted into a running summary so the agent stays coherent across many steps without you managing tokens by hand. Continuation handles the other direction: when a single response is truncated by length, the runtime automatically continues generating to assemble the full reply.

import { Agent } from '@a3s-lab/code';

const agent = await Agent.create('agent.acl');

const session = agent.session('/repo', {
  // Compact older turns once context fills past the threshold.
  autoCompact: true,
  autoCompactThreshold: 0.75,
  // Auto-continue a single response that the model truncates by length.
  continuationEnabled: true,
  maxContinuationTurns: 3,
});

// Run a long, multi-step task. The runtime compacts older turns as needed;
// you never touch the token math.
for (let i = 0; i < 50; i++) {
  await session.send(`Step ${i}: continue refactoring the parser`);
}

// Inspect what the session is currently carrying.
console.log('history turns:', session.history().length);
console.log('recent memory:', await session.memoryRecent(5));

session.close();

from a3s_code import Agent, SessionOptions

agent = Agent.create("agent.acl")

opts = SessionOptions()
# Compact older turns once context fills past the threshold.
opts.auto_compact = True
opts.auto_compact_threshold = 0.75
# Auto-continue a single response that the model truncates by length.
opts.continuation_enabled = True
opts.max_continuation_turns = 3
session = agent.session("/repo", opts)

# Run a long, multi-step task. The runtime compacts older turns as needed;
# you never touch the token math.
for i in range(50):
    session.send(f"Step {i}: continue refactoring the parser")

# Inspect what the session is currently carrying.
print("history turns:", len(session.history()))
print("recent memory:", session.memory_recent(5))

session.close()

Use auto-compaction for long sessions where you want the runtime to manage context pressure for you. autoCompactThreshold / auto_compact_threshold is a fraction of the context window (0.0–1.0, default 0.8) at which compaction kicks in; lower it to compact earlier. Inspect the live session with history() (synchronous) and memoryRecent / memory_recent.