pi-meridian-extension

Use your Claude Max subscription through pi via Meridian — a local proxy that bridges the Anthropic Messages API with Claude Code SDK authentication.

Without this extension, pi's default system prompt triggers an "You're out of extra usage" error on Claude Opus 4.6 (and potentially other models) when routed through Meridian. This extension rewrites the system prompt only for Meridian requests to avoid that issue, while leaving all other providers untouched.

What it does

• Registers a meridian provider with 5 Claude models (Sonnet 4.5, Opus 4.5, Sonnet 4.6, Opus 4.6, Haiku 4.5)
• Rewrites the system prompt for Meridian requests to avoid the extra-usage error, preserving project context and working directory
• Auto-starts Meridian on session start if the proxy isn't running
• Adds commands: /meridian (health check), /meridian start, /meridian version

Models

| ID | Name | |----|------| | meridian/claude-sonnet-4-5 | Claude Sonnet 4.5 | | meridian/claude-opus-4-5 | Claude Opus 4.5 | | meridian/claude-sonnet-4-6 | Claude Sonnet 4.6 | | meridian/claude-opus-4-6 | Claude Opus 4.6 | | meridian/claude-haiku-4-5 | Claude Haiku 4.5 |

Use them with --model, e.g. --model meridian/claude-opus-4-6:high.

Install

pi install npm:pi-meridian-extension

Requires Meridian installed globally:

npm install -g @rynfar/meridian

Configuration

| Env var | Default | Description | |---------|---------|-------------| | MERIDIAN_BASE_URL | http://127.0.0.1:3456 | Meridian proxy URL |

Switch to Meridian

After installing, switch your model in pi:

/model meridian/claude-opus-4-6:high

Or use it for a single command:

pi --model meridian/claude-opus-4-6:high

Commands

• /meridian — health check (connection status, auth, mode)
• /meridian start — start the Meridian daemon if not running
• /meridian version — check installed vs latest version, update availability

How the prompt rewrite works

When provider === "meridian", the extension hooks before_provider_request and replaces the full system prompt with a concise version that:

1. Identifies as Claude Code operating through Meridian for pi
2. Preserves your # Project Context section from the original prompt
3. Preserves Current date: and Current working directory: lines
4. Drops pi's heavy default prompt that triggers the extra-usage error

All other providers continue to use pi's default system prompt unchanged.