Show context compaction events in studio code CLI#3019
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The Agent SDK emits system messages when it shrinks context (compacting status, compact_boundary, microcompact_boundary) but the CLI UI ignored them, so long sessions appeared to stop suddenly while the SDK was silently managing context. Surface these events as informational messages and as a loader status during compaction. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Track the model's input + cache token counts against the reported contextWindow on every result message and render the percentage in the prompt footer alongside the existing status message, so users can see how full the context window is before it triggers compaction. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
The previous version divided result.modelUsage cumulative totals by contextWindow, which inflated the percentage in multi-iteration turns (each iteration's cached reads were summed, so an 11-iteration turn could report > 100% even when no single API call was close to the window). Track the last assistant message's usage snapshot instead — that reflects the actual prompt size sent on the most recent API call — and cache the context window from result messages so the label can update mid-turn as iterations stream in. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
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Related issues
Proposed Changes
The Claude Agent SDK emits
systemmessages when it manages the context window, but thestudio codeCLI UI only handledassistant,user, andresultmessages. As a result, long agent turns appeared to "stop suddenly" while the SDK was silently compacting context in the background.This PR wires up the missing message types in
apps/cli/ai/ui.ts:handleMessage:status: compacting— sets the loader message to "Compacting context…" so users see why the turn has paused.compact_boundary— shows an info message when the SDK summarizes the transcript, including the trigger (auto/manual) and the token count before compaction.microcompact_boundary— shows an info message when the SDK drops old tool-result attachments (screenshots, large tool outputs) to free tokens without summarizing the full transcript. Includes the number of attachments dropped and tokens saved.The
microcompact_boundarytype isn't in the public SDK type definitions yet, so it's narrowed via a defensive cast.Testing Instructions
npm run cli:buildnode apps/cli/dist/cli/main.mjs codePre-merge Checklist