Claude API adds on-demand compaction: reusable signed summaries
A beta swaps old turns for one signed block while keeping recent messages verbatim — plus live Managed Agents sessions and a 17% Claude Code limit cut.
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Compact a whole conversation in one API call
Add the top-level `compaction` parameter with the `compact-2026-09-04` beta header and the Messages API hands back one signed block summarizing everything you sent — you send that block first on later requests in place of the old messages. You choose when to fire it and the call can run in the background, so a long-running agent stops re-uploading a growing transcript on every turn. It's live on the Claude API (not Bedrock or Vertex) across Opus 5/4.8/4.7/4.6, Sonnet 5/4.6, and the Fable and Mythos 5.x models.
Keep your latest turns word-for-word
Send only the older messages to the compaction request and leave the recent turns out; put the returned block first, then append those turns untouched. On Fable and Mythos 5.1 the kept turns' thinking stays valid as long as the system prompt and non-deferred tools match the compaction request. Two catches: images, documents, and fetched URLs inside summarized turns are lost, and every summarize call is billed separately at full rates (it lands as a `compaction` entry in `usage.iterations`).
Attach your terminal to a live cloud agent
`ant beta:sessions connect` hooks your terminal onto a running Claude Managed Agents session — follow it live, send messages, and approve or deny the tool calls it's blocked on; pass `--web` to open the Console's session viewer locally instead. Fire-and-forget cloud agents become something you can actually watch and steer without switching to a browser tab.
Elsewhere: Claude Code weekly limits drop 17%
Anthropic cut Claude Code's current weekly limits by roughly 17% as the summer usage boost expired, and some subscribers are publicly canceling over it. If you live in Claude Code, plan for fewer runs a week — or lean on the new compaction beta to stretch each session further.
Elsewhere: Copilot CLI learns to pause and resume
GitHub Copilot CLI v1.0.84-8 lets you pause and resume agent-factory runs, adds concise transcript-view work summaries, and refreshes model lists after you re-authenticate. Small, but it means a long agent run no longer has to finish in one sitting.