Practical tips & mental models
Based on Sankalp's guide to Claude Code 2.0
Don't just "keep up" with AI releases. Build a system for getting better.
Know what tools exist. Try new features when they ship. The landscape moves weekly.
The better you understand your problem, the better you can prompt. Domain knowledge is the multiplier.
Try throw-away first drafts. Learn the model's biases. Build taste through iteration.
These three compound. Tools without domain expertise = slop. Domain expertise without tools = slow. Both without experimentation = stagnant.
// What the model sees every API call: { "system": "You are a coding agent...", // ~500 tokens "tools": [bash, read, write, edit, ...], // ~2,000 tokens "messages": [ {"user": "Fix the auth bug"}, // ~10 tokens {"assistant": tool_use(read_file)}, // ~50 tokens {"user": tool_result("...500 lines...")}, // ~2,000 tokens {"assistant": tool_use(read_file)}, // ~50 tokens {"user": tool_result("...300 lines...")}, // ~1,200 tokens // ... 15 more tool calls ... // Context is now 80% full of file contents ] }
Every file you read, every command you run — it all stays in the window. This is why agents "forget" things on long tasks. The useful information gets drowned out.
Tags injected at runtime that keep objectives top-of-mind. The model re-reads these every turn.
Not just for tracking — they're attention manipulation. The model sees the plan every turn and stays on track.
Claude Code can compress old context into summaries. Trades detail for headroom. Use /compact.
Sometimes the best move is to start over. Use /handoff to summarize before you go.
The best agent users are context hygienists.
| Agent | Access | Use When |
|---|---|---|
| Explore | Read-only, fresh context | Searching the codebase, finding files, understanding structure |
| Plan | Read-only, inherits context | Designing implementation strategy before coding |
| General-purpose | Full tools, inherits context | Complex research, multi-step exploration |
| claude-code-guide | Docs only | Looking up Claude Code features and settings |
Key insight: Explore starts with a fresh context — it doesn't see your conversation history. This is a feature, not a bug. It forces focused work and returns only a clean summary to your main session.
# skills/my-skill/SKILL.md --- name: my-skill description: When to trigger this --- # Instructions for the model Step 1: ... Step 2: ...
// .claude/settings.json { "hooks": { "Stop": [{ "command": "afplay /System/Library/ Sounds/Glass.aiff" }] } }
# .claude/commands/handoff.md
Summarize this session:
- What was accomplished
- What's left to do
- Key decisions made
- Files changed
Format as a handoff note for
a fresh session to continue.
Pro tip: Use /handoff before starting a fresh session. Preserves knowledge, resets context.
Ask clarifying questions. Use Explore sub-agent for codebase search. Understand before you act.
Use /ultrathink for complex tasks. Review changes carefully. Micro-manage at first — trust builds over time.
Throw-away first drafts are your friend. The first attempt teaches you the model's biases. The second attempt is informed.
Always review generated code. Use a different model for review if possible — fresh eyes catch different bugs.
Use /ultrathink for anything non-trivial. Lets the model reason more deeply before acting. Worth the extra tokens.
Esc+Esc or /rewind to roll back. Git-like safety net. Use it before risky operations.
/context shows token usage. When you're past 50%, consider compacting or starting fresh.
Don't commit to the first output. Use it to learn the model's approach, then guide the second attempt with that knowledge.
Maintain a CLAUDE.md in your repo with project context. Use a scratchpad file for the model to think in.
Ctrl+R to search previous prompts. Stop retyping the same instructions.
| Model | Strength | Weakness | Best For |
|---|---|---|---|
| Opus 4.5 | Speed, communication, collaboration | 200K context limit | Primary driver, pair programming |
| Sonnet 4.5 | Fast, cheap | Prone to "slop" — haphazard changes | Simple tasks, quick edits |
| GPT-5.x Codex | Raw code generation, 400K context | Slower, less conversational | Code review, second opinion |
| Open source | Free, private, customizable | Lower capability ceiling | Low-medium complexity, offline |
Pro tip: Use one model to write and a different model to review. Fresh perspective catches bugs the author misses.
"It's a little spirit/ghost that lives on your computer" — Karpathy, on AI agents
Happy building.
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