Summarization And Context

Summarization in Agent SDK is built for autonomous agents that may run long enough to outgrow the model-facing context window.

Why this exists

Autonomous agents tend to accumulate:

• large tool outputs
• repeated tool call traces
• intermediate assistant turns
• memory and planning context

Without compaction, that state becomes expensive, noisy, and eventually unusable.

What summarization actually does

The smart runtime can compact conversation and tool history when the configured context budget is under pressure.

The important part is what it does not do:

• it does not blindly erase the past
• it does not require the application to manually rewrite messages
• it does not remove recovery options for archived tool outputs

Key knobs

const agent = createSmartAgent({
  model,
  tools,
  summarization: {
    enable: true,
    maxTokens: 24000,
    summaryTriggerTokens: 17000,
    summaryMode: "incremental",
  },
  context: {
    policy: "hybrid",
    toolResponsePolicy: "summarize_archive",
  },
});

Important fields:

• summarization.enable
• summarization.maxTokens
• summarization.summaryTriggerTokens
• summarization.summaryMode
• context.toolResponsePolicy
• toolResponses.largeResponsePolicy

Recovery after compaction

When large tool outputs are summarized and archived, the runtime keeps a recovery path through get_tool_response.

That means an autonomous agent can continue with compact context, then fetch raw evidence again if it later needs the original output.

State surfaces to inspect

• state.summaryRecords
• state.toolHistoryArchived
• state.watchdog

These surfaces tell you not only that summarization happened, but also what kind of context pressure the runtime was managing.

When autonomous agents benefit most

Summarization is especially helpful when the agent:

• performs repeated search or retrieval
• calls MCP tools that return large payloads
• uses multi-step planning over a longer session
• needs resume and recovery without replaying every raw tool result into live context

When to disable it

You can turn summarization off for debugging or short deterministic runs:

const agent = createSmartAgent({
  model,
  tools,
  summarization: false,
});

That is usually appropriate only when the task is short or when you are inspecting exact raw transcripts for debugging.

Design rule to remember

Summarization is not a cosmetic feature. It is a runtime survival mechanism for agents that need to think and act across longer horizons.