Feature Request: Expose session cost and account balance in status line JSON input

Summary

The status line command currently receives JSON data with model info, context window usage, and rate limits. It would be very useful to also include session cost and account balance/credits information, so users can monitor their spending directly in the status bar.

Motivation

• The /cost command already tracks session spending internally, but this data is only accessible via a manual command — not programmatically in the status line.
• Users who pay per API usage want to keep an eye on their spending without interrupting their workflow.
• Account balance is tracked on console.anthropic.com but having at least a session cost field in the status line would already be a big improvement.

Proposed additions to status line JSON

{
  "cost": {
    "session_total_usd": 0.55,
    "session_input_tokens": 125000,
    "session_output_tokens": 42000
  }
}

Optionally, if technically feasible:

{
  "account": {
    "remaining_credits_usd": 12.50
  }
}

Use case

A status line script could then display something like:

MyProject | Opus | Context: [▓▓▓░░░░░░░] 30% | Session: $0.55

This gives users real-time cost awareness without leaving their workflow.

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🤖 This issue was written with Claude Code.