What's the story around context tracking?

[iamthebot]

Should plugins integrating with claude-code-acp keep track of the context window themselves? I couldn't find anything in the ACP protocol itself that would suggest how we should keep track of context.

I'm interested in exposing the context used % in codecompanion (especially since slash commands with TUIs like /context aren't supported in the claude code SDK) but wanted to better understand how it's supposed to work here.

[benbrandt]

Just to clarify: you want to see in the UI how much context is being used?
This is on the roadmap for sure.

And by plugin do you mean a Claude Code plugin? Or a client that is running this as an ACP agent?

[iamthebot]

Yes, I'd like the editor to expose context use.

I'm working on Neovim's codecompanion plugin. But ideally this context info is surfaced in this ACP connector itself so all editors (including Zed and Neovim) can support it.

[josevalim]

This is what Claude Code SDK makes available and I am unsure on how to transform this into something useful:

"total_cost_usd": 0.01331,
  "usage": {
    "input_tokens": 3,
    "cache_creation_input_tokens": 29,
    "cache_read_input_tokens": 13093,
    "output_tokens": 338,
    "server_tool_use": {
      "web_search_requests": 0
    },
    "service_tier": "standard",
    "cache_creation": {
      "ephemeral_1h_input_tokens": 0,
      "ephemeral_5m_input_tokens": 29
    }
  },
  "modelUsage": {
    "claude-haiku-4-5-20251001": {
      "inputTokens": 0,
      "outputTokens": 118,
      "cacheReadInputTokens": 0,
      "cacheCreationInputTokens": 0,
      "webSearchRequests": 0,
      "costUSD": 0.00059,
      "contextWindow": 200000
    },
    "claude-sonnet-4-5-20250929": {
      "inputTokens": 0,
      "outputTokens": 848,
      "cacheReadInputTokens": 0,
      "cacheCreationInputTokens": 0,
      "webSearchRequests": 0,
      "costUSD": 0.012719999999999999,
      "contextWindow": 200000
    }
  }