Summary

rtk discover reports commands as "missed savings" even when they are actively being rewritten by a PreToolUse hook. The transcript logs the pre-hook command (what Claude requested), but the hook rewrites it before execution. discover scans the pre-hook text and doesn't account for the rewrite, producing inflated numbers.

Reproduction

1. Configure a PreToolUse hook in Claude Code settings.json that rewrites commands via rtk hook claude:

   {
     "hooks": {
       "PreToolUse": [{
         "matcher": "Bash",
         "hooks": [{ "type": "command", "command": "/path/to/rtk-unified.sh" }]
       }]
     }
   }

2. The hook correctly rewrites commands — verified by piping test inputs through rtk hook claude:

   $ echo '{"tool_input":{"command":"git diff"}}' | rtk hook claude
   {"hookSpecificOutput":{"hookEventName":"PreToolUse","permissionDecisionReason":"RTK auto-rewrite","updatedInput":{"command":"rtk git diff"}}}
   
   $ echo '{"tool_input":{"command":"rg -n \"pattern\" src/"}}' | rtk hook claude
   {"hookSpecificOutput":{"hookEventName":"PreToolUse","permissionDecisionReason":"RTK auto-rewrite","updatedInput":{"command":"rtk grep -n \"pattern\" src/"}}}
   

3. Run rtk discover --all --since 7:

   Already using RTK: 1036 commands (14.5%)
   
   MISSED SAVINGS
   git diff    922    ~148.3K tokens
   rg -n       973    ~81.4K tokens
   ls -la      424    ~16.8K tokens
   find        249    ~47.1K tokens
   ...
   Total: 3431 commands -> ~410.6K tokens saveable
   

4. But rtk gain confirms those commands ARE being processed through RTK:

   Total commands: 1167
   rtk grep: 201, rtk read: 216, rtk git diff, rtk git commit: 38, ...
   

Root cause

Claude Code session transcripts (.jsonl) log tool_input.command — the pre-hook command. The hook emits updatedInput to rewrite it, but the transcript preserves the original. rtk discover scans the original and doesn't check whether a hook rewrite occurred.

Suggested fix

One or more of:

• Detect the presence of an RTK PreToolUse hook and exclude commands that would match rtk hook claude from the "missed" count
• Cross-reference against rtk gain data to filter already-processed commands
• Note in the output when a hook is detected: "Note: PreToolUse hook active — these commands may already be rewritten at execution time"

Environment

• rtk 0.42.3
• Claude Code with PreToolUse hook via rtk hook claude
• Linux