Overview

You’re deep in a complex refactoring session with Claude Code and something comes to mind: “What was the reason this function was deprecated again?” Typing it into the main prompt dirties your conversation history and risks breaking the agent’s context. /btw is the side question feature designed to solve exactly this problem.

How /btw Works

graph TD
    A["Main Conversation in Progress"] --> B["/btw Question Input"]
    B --> C["Reads Full Conversation Context <br/> Code already read, decisions agreed upon"]
    C --> D["One-shot Overlay Response"]
    D --> E["Close with Space/Enter/Escape"]
    E --> F["Main Conversation History <br/> Unchanged"]
    style D fill:#2196F3,color:#fff
    style F fill:#4CAF50,color:#fff

Key properties:

• Context access: Reads the full context of the current conversation — code already seen, decisions made, everything discussed so far.
• History isolation: The question and answer are handled as a one-shot overlay and never written to the main conversation history.
• Non-blocking: You can invoke /btw even while Claude is generating its main response. It does not interrupt the main output.

/btw vs Subagent: Different Tools for Different Jobs

Rule of thumb:

• “Something Claude probably already knows” → /btw
• “Something that requires fresh research or exploration” → Subagent

Limitations

No Tool Access

/btw cannot use any tools — no file reading, command execution, or web search. It answers purely from what is already in the current conversation context. This is intentional: if tool calls were allowed, a side question could interfere with the main task.

Single-Turn Only

If you need follow-up questions and a back-and-forth exchange, use a regular prompt instead. /btw is literally “by the way” — one quick question, then move on.

Cost

/btw is designed to reuse the parent conversation’s prompt cache, so no new context needs to be built. If you’re watching your Claude Code token costs, quick confirmations are cheapest as /btw questions.

Practical Usage Patterns

# Quick check during refactoring
/btw Which method was it that you said was deprecated earlier in this file?

# Convention check during code review
/btw Are we using try-catch or a Result type for error handling in this project?

# Referencing a past decision during design discussion
/btw What was the reason we went with PostgreSQL earlier?

Insight

/btw looks like a small feature, but it fills an important gap in Claude Code’s conversation model. There was no way to leverage context without polluting the main conversation. This design reflects a real pattern in how developers think during work — “wait, what was that again?” — without stopping what they’re doing. The constraints (no tool access, single-turn) are intentional guardrails to ensure side questions never disrupt the main workflow.