Observability proxy for Claude Code — see what's happening between Claude and the Anthropic API.
What is Aspy?
Aspy sits between Claude Code and the Anthropic API, intercepting all traffic and giving you visibility into tool calls, thinking blocks, token usage, and costs. Run it as a TUI proxy, integrate via MCP, or install the Claude Code plugin.
What It Does
- Real-time TUI — Watch tool calls, thinking blocks, and API responses as they stream
- Token & cost tracking — Cumulative session statistics with per-model pricing
- Thinking capture — Dedicated panel showing Claude's reasoning in real-time
- Structured logs — JSON Lines format for analysis with
jq
- Multi-client routing — Track multiple Claude Code instances through one proxy
- REST API & MCP — Programmatic access to session data
Get Started
Option 1: TUI Proxy (Binary)
Download from GitHub Releases or build from source:
cargo install --git https://github.com/omgpointless/aspy
Run the proxy:
# Windows
.\aspy.exe
# macOS/Linux
./aspy
Point Claude Code at it:
# In a new terminal
export ANTHROPIC_BASE_URL=http://127.0.0.1:8080
claude
Optionally: MCP Server
Add aspy to Claude Code's MCP servers:
claude mcp add aspy -- npx -y aspy-mcp
This gives Claude Code access to:
- Current session:
aspy_stats, aspy_events, aspy_context
- Lifetime history:
aspy_recall, aspy_lifetime (semantic + keyword search)
- Context recovery: Search past thinking blocks, prompts, and responses across all sessions
Note: Requires the TUI proxy running to collect data.
Optionally: Claude Code Plugin
Install the plugin for slash commands:
/plugin marketplace add omgpointless/aspy
After restarting Claude Code, use /aspy:stats to query session metrics. The plugin also includes automatic cargo fmt hooks for Rust projects.
Demo Mode
Try the TUI without Claude Code:
ASPY_DEMO=1 ./aspy
Generates mock events to showcase the interface.
Documentation
Package Managers
Homebrew, Scoop, and Chocolatey packages will be available when the project stabilizes.
About
Maintainer's first Rust project. Learning journey together with Claude Code which is the whole reason I built this tool to start with.
License
MIT
