ctok - Zed Extension

Estimate Claude token counts, analyze costs, and refine prompts directly in Zed's AI assistant panel.

All heavy lifting is delegated to the ctok CLI; this extension is a thin Rust/WASM wrapper that runs the binary and formats results as Markdown.

Requirements

• Zed 0.150+
• ctok CLI installed: npm i -g @ctok/cli

Installation

From Zed Extension Registry

1. Open Zed → Extensions (Cmd+Shift+X)
2. Search for ctok
3. Click Install

From Source

cd apps/zed
cargo build --release --target wasm32-wasip1
# Then load the extension directory in Zed's dev extension path

Usage

Open the AI assistant panel (Cmd+?) and type a slash command:

Command	Description
/ctok-check <text>	Estimate tokens and cost for the given text
/ctok-refine <text>	Refine a prompt - shows the improved version + savings
/ctok-scan	Scan the current project directory

Examples

Estimate tokens for a prompt:

/ctok-check Refactor the authentication middleware to use Postgres sessions

Refine a vague prompt:

/ctok-refine Please help me handle the auth thing somehow in a better way

Scan the current project:

/ctok-scan

Development

Build the WASM target:

# Install the wasm32-wasip1 target
rustup target add wasm32-wasip1

# Build release
cargo build --release --target wasm32-wasip1

Check types without WASM compilation:

cargo check

License

MIT