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Tutorial March 11, 2026 2 min read

Archive Your mariozechner/coding-agent Sessions with unfirehose

Mario Zechner’s coding agent (currently called pi-coding-agent) is a minimal terminal coding agent with one of the best extension systems in the space. Almost everything — sub-agents, plan mode, MCP, compaction — ships as an extension. The core stays thin.

unfirehose ships an extension that hooks into that lifecycle and writes every session as unfirehose/1.0 JSONL. No patches to the agent. No wrapper scripts. Drop in one file and your sessions are archived.

What You Get

Every coding session produces a JSONL file at ~/.pi/projects/{project}/{session}.jsonl containing:

  • Session envelope — project, working directory, harness version, timestamps
  • Every message — user prompts, assistant responses, tool calls, tool results
  • Thinking blocks — extended reasoning captured as type: "reasoning" content blocks
  • Token usage — input, output, cache read/write per turn
  • Model changes — tracked when you switch providers mid-session
  • Tool name normalization — readFile becomes Read, executeCommand becomes Bash, matching the canonical unfirehose vocabulary across all harnesses

Install

The extension ships in the @unturf/unfirehose-schema npm package. Two ways to install:

Copy the file

npm pack @unturf/unfirehose-schema --pack-destination /tmp
tar xf /tmp/unturf-unfirehose-schema-*.tgz -C /tmp
cp /tmp/package/extensions/pi-unfirehose.ts ~/.pi/agent/extensions/unfirehose.ts

Symlink from node_modules

If you already have @unturf/unfirehose-schema installed in a project:

ln -s node_modules/@unturf/unfirehose-schema/extensions/pi-unfirehose.ts \
  ~/.pi/agent/extensions/unfirehose.ts

That’s it. Next time you start a coding session, JSONL starts flowing.

Configure (Optional)

Add to ~/.pi/agent/settings.json to change the output directory:

{
  "unfirehose": {
    "outputDir": "~/.pi/projects"
  }
}

The default (~/.pi/projects) works out of the box. Sessions are organized by project slug derived from your working directory.

What the JSONL Looks Like

Each line is a self-contained JSON object tagged with $schema: "unfirehose/1.0". A session starts with an envelope:

{"$schema":"unfirehose/1.0","type":"session","id":"019506a8-...","projectId":"~-myproject","status":"active","harness":"pi"}

Followed by messages:

{"$schema":"unfirehose/1.0","type":"message","role":"user","content":[{"type":"text","text":"fix the login page"}]}
{"$schema":"unfirehose/1.0","type":"message","role":"assistant","model":"claude-sonnet-4-20250514","provider":"anthropic","content":[{"type":"text","text":"I'll check the CSS..."},{"type":"tool-call","toolName":"Read","input":{"path":"src/login.css"}}],"usage":{"inputTokens":1200,"outputTokens":340}}

Same format as Claude Code, Gemini CLI, Aider, and every other harness in the unfirehose ecosystem. One schema, one dashboard, every agent.

View in the Dashboard

If you’re running the unfirehose dashboard locally, it picks up ~/.pi/projects/ automatically. Your coding agent sessions show up alongside Claude Code sessions, Fetch sessions, and everything else — unified timeline, token tracking, thinking block viewer, the works.

Multi-Provider Support

The coding agent supports OpenAI, Anthropic, and Google models through its unified @mariozechner/pi-ai layer. The unfirehose extension normalizes all of them to canonical provider names (anthropic, openai, google, local), so your archive stays consistent regardless of which model you use.

A Note on the Name

The coding agent is currently published as @mariozechner/pi-coding-agent. The name has no relation to Raspberry Pi — it appears to be an arbitrary choice. We refer to it as mariozechner/coding-agent here to avoid confusion. If you landed on this page looking for Raspberry Pi support, this is not that.

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