Token Optimization
Best practices
Prompt patterns that keep token usage low.
1. Always seed the conversation with MCP-first instruction
If you used larkx init, this is already done via the UserPromptSubmit hook. If not, add one line to your CLAUDE.md / .cursorrules:
bash
Always use larkx MCP tools first for any code navigation:
get_project_index, search_symbol, get_file_summary, get_impact, get_call_chain, get_dead_code.
Only fall back to reading files when MCP returns no result.2. Tell the AI to start cheap
Add to your agent prompt: "Begin with get_project_index level 1. Only request higher levels if needed for the specific task."
3. Use folder scoping aggressively
When you know which subtree matters, tell the AI:
bash
# Bad
"Refactor my authentication code"
# Better
"Refactor my auth code in src/auth. Use folder scoping when calling get_project_index."4. Prefer specific tools over broad ones
| If asking… | Use this tool | Not this |
|---|---|---|
| "Where is X?" | search_symbol | get_project_index |
| "What's in this file?" | get_file_summary | Reading the file |
| "What if I change Y?" | get_impact | Grep across project |
5. Avoid re-reading after compaction
When context auto-compacts, the AI often re-explores. Keep an llms.txt or pinned message with the key file map so the AI doesn't re-fetch get_project_index repeatedly.
6. Index regularly
Stale index = AI tries paths that don't exist anymore. Use larkx index --watch during active development.