[Feature Request] Add automatic cost reporting on session exit

Bug Description
Claude should have a way to report /cost at the end of a session or session exit regardless of exit strategy.

⏺ Unfortunately, it doesn't look like there's a built-in way to have Claude automatically run /cost before exiting. The SessionEnd hook runs after the
session ends, so the session state (where /cost gets its data) is already gone.

Your options are:

1. Manual /cost before exit - Just run /cost manually before you exit each session (what you're already doing)
2. Shell alias - Create a shell alias that runs /cost then exits:

alias cexit='claude cost && exit'

1. SessionEnd hook with transcript parsing - The script I tried to create would parse the transcript file to calculate costs, but this would be an

approximation based on parsing the JSONL usage data

1. Feature request - This seems like a legitimate feature gap - Claude Code should probably print cost summary automatically on exit, similar to how

many CLI tools print summary statistics

The fundamental issue is that /cost relies on in-memory session state that's cleaned up before SessionEnd hooks run. There's no "BeforeSessionEnd"
hook that would allow capturing this data while it's still available.

This is what claude tried^^

Environment Info

• Platform: darwin
• Terminal: iTerm.app
• Version: 2.0.19
• Feedback ID: a4017781-d2dc-491d-b86a-4f0a94c65b1c

Errors

[{"error":"SyntaxError: Unexpected token '`', \"```json\n{\n\"... is not valid JSON\n    at JSON.parse (<anonymous>)\n    at file:///Users/harrison.katz/.claude/local/node_modules/@anthropic-ai/claude-code/cli.js:62:719\n    at Q (file:///Users/harrison.katz/.claude/local/node_modules/@anthropic-ai/claude-code/cli.js:8:15093)\n    at Pi2 (file:///Users/harrison.katz/.claude/local/node_modules/@anthropic-ai/claude-code/cli.js:1056:20444)\n    at process.processTicksAndRejections (node:internal/process/task_queues:95:5)","timestamp":"2025-10-16T16:37:08.166Z"},{"error":"SyntaxError: Unexpected token '`', \"```json\n{\n\"... is not valid JSON\n    at JSON.parse (<anonymous>)\n    at file:///Users/harrison.katz/.claude/local/node_modules/@anthropic-ai/claude-code/cli.js:62:719\n    at Q (file:///Users/harrison.katz/.claude/local/node_modules/@anthropic-ai/claude-code/cli.js:8:15093)\n    at Pi2 (file:///Users/harrison.katz/.claude/local/node_modules/@anthropic-ai/claude-code/cli.js:1056:20444)\n    at process.processTicksAndRejections (node:internal/process/task_queues:95:5)","timestamp":"2025-10-16T17:12:40.486Z"},{"error":"AxiosError: Request failed with status code 404\n    at MO (file:///Users/harrison.katz/.claude/local/node_modules/@anthropic-ai/claude-code/cli.js:24:1136)\n    at IncomingMessage.<anonymous> (file:///Users/harrison.katz/.claude/local/node_modules/@anthropic-ai/claude-code/cli.js:29:9845)\n    at IncomingMessage.emit (node:events:536:35)\n    at IncomingMessage.emit (node:domain:489:12)\n    at endReadableNT (node:internal/streams/readable:1698:12)\n    at process.processTicksAndRejections (node:internal/process/task_queues:82:21)\n    at K31.request (file:///Users/harrison.katz/.claude/local/node_modules/@anthropic-ai/claude-code/cli.js:31:2129)\n    at process.processTicksAndRejections (node:internal/process/task_queues:95:5)\n    at async b0Q (file:///Users/harrison.katz/.claude/local/node_modules/@anthropic-ai/claude-code/cli.js:2416:1062)\n    at async f0Q (file:///Users/harrison.katz/.claude/local/node_modules/@anthropic-ai/claude-code/cli.js:2416:2055)\n    at async Object.call (file:///Users/harrison.katz/.claude/local/node_modules/@anthropic-ai/claude-code/cli.js:2416:8350)\n    at async hl5 (file:///Users/harrison.katz/.claude/local/node_modules/@anthropic-ai/claude-code/cli.js:2574:64999)\n    at async aZQ (file:///Users/harrison.katz/.claude/local/node_modules/@anthropic-ai/claude-code/cli.js:2574:62053)\n    at async file:///Users/harrison.katz/.claude/local/node_modules/@anthropic-ai/claude-code/cli.js:2574:61222\n    at async nl2 (file:///Users/harrison.katz/.claude/local/node_modules/@anthropic-ai/claude-code/cli.js:724:1644)\n    at async fl5 (file:///Users/harrison.katz/.claude/local/node_modules/@anthropic-ai/claude-code/cli.js:2574:61134)","timestamp":"2025-10-16T17:14:42.007Z"},{"error":"SyntaxError: Unexpected token '`', \"```json\n{\n\"... is not valid JSON\n    at JSON.parse (<anonymous>)\n    at file:///Users/harrison.katz/.claude/local/node_modules/@anthropic-ai/claude-code/cli.js:62:719\n    at Q (file:///Users/harrison.katz/.claude/local/node_modules/@anthropic-ai/claude-code/cli.js:8:15093)\n    at Pi2 (file:///Users/harrison.katz/.claude/local/node_modules/@anthropic-ai/claude-code/cli.js:1056:20444)\n    at process.processTicksAndRejections (node:internal/process/task_queues:95:5)","timestamp":"2025-10-16T17:16:27.443Z"}]