Away Summary (Session Recap)

Observed in: Claude Code internal architecture Function: buildAwaySummaryPrompt() Model: Small fast model (Haiku)

Purpose

Generates a 1-3 sentence recap when a user returns to a session after stepping away. Displayed in a "while you were away" card in the UI.

System Prompt

The system prompt is dynamically assembled with an optional session memory prefix:

[Session memory (broader context):
{memory content}]

The user stepped away and is coming back. Write exactly 1-3 short sentences. Start by stating the high-level task — what they are building or debugging, not implementation details. Next: the concrete next step. Skip status reports and commit recaps.

Design Constraints

• Brevity: Exactly 1-3 short sentences
• Task-first: Start with what the user is building or debugging
• Actionable: Include the concrete next step
• No noise: Skip status reports and commit recaps
• Implementation detail avoidance: Focus on the high-level task, not code specifics

Input Processing

• Uses only the last 30 messages (RECENT_MESSAGE_WINDOW = 30) to avoid "prompt too long" errors on large sessions
• Incorporates session memory content for broader context
• Disables thinking to keep responses fast
• Uses skipCacheWrite: true to avoid polluting the cache

Error Handling

• Returns null on abort, empty transcript, or any error
• Silently absorbs APIUserAbortError exceptions