History Window

Overview

historyWindow caps the number of trailing items projected to the LLM each turn. Storage (itemLog, session.accumulatedItems, session JSON) is untouched — the cap is a pure projection over the value handed to assembleView. Long-running sessions stay within the model's context window without losing transcript history.

• Slot: 275 (after recall-contributing layers)
• Default scope: 'execution'
• Default maxItems: 40
• Hook: projectHistory only (no recall, no state)

Usage

import { historyWindow, observationalMemory, workingMemory } from '@noetic/core';

const memory = [
  workingMemory(),
  observationalMemory(),
  historyWindow({ maxItems: 40 }),
];

Algorithm

On every LLM step, the layer:

1. Slices the trailing maxItems from the input.
2. Walks backward to ensure the projected window contains at least one user message AND one assistant message. If the slice lacks either role, the cap is temporarily exceeded — the minimum-exchange guarantee.
3. Drops any orphan function_call / function_call_output whose pair fell outside the slice. (OpenRouter rejects unpaired tool items, so this is required.)

Storage isolation

The projection runs against ctx.itemLog.items but never mutates it. As a result:

• Session save/restore — saved JSON contains the entire transcript.
• getAgentResponse() — returns all items the agent emitted this session.
• TUI transcript views — display the full conversation.
• itemLog.items.length — grows unbounded; the cap only narrows the projection used by assembleView.

Mid-round in-flight items are not capped

Within a single callModel invocation's tool loop, that round's own function_call and function_call_output items accumulate in the wire payload until the call returns. The cap fires at turn boundaries, not mid-call — capping mid-flight would corrupt the active tool flow.

CLI configuration

The CLI installs historyWindow only when AgentConfig.history.maxItems is set. When unset, history is uncapped (the pre-existing default behaviour). Configure it via:

• noetic.config.ts:

  export default {
    // ...
    history: { maxItems: 40 },
  } satisfies AgentConfig;

• /config slash command → Memory tab → History Window (items). Leave blank to disable.

Spawned sub-agents (teammates) inherit the same cap by default.