format-claude-stream

[!NOTE] format-claude-stream is not accepting contributions. We’re releasing the code for others to refer to and learn from, but we are not open to pull requests or issues at this time.

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Summary

A CLI filter to turn Claude's streaming JSON output into human-readable text.

In addition to the usual Claude output, format-claude-stream prints:

• Chain-of-thought
• All tool calls, and their results, in an easy-to-read format
• Tool call errors
• A raw JSON dump of any events it doesn't understand.

Output is color-coded to make it easier to scan.

With format-claude-stream, you can print the live stream or dump the JSON to a file and audit it later. With tee (see below), you can do both!

Installation

npm install -g @khanacademy/format-claude-stream

Usage

CLI

claude --print --verbose --output-format stream-json | format-claude-stream

You can use tee to duplicate the output to a timestamped file:

claude --print --verbose --output-format stream-json \
  | tee "claude-$(date +'%Y-%m-%d_%H%M%S').jsonl" \
  | format-claude-stream

Library

import {ClaudeStreamFormatter, StandardOutput, ChalkColorizer} from "@khanacademy/format-claude-stream";

const claudeStreamFormatter = new ClaudeStreamFormatter(
    new StandardOutput(),
    new ChalkColorizer(),
);

await claudeStreamFormatter.write(JSON.parse(streamLine));

Development

Requirements:

node >= 20.20.0
pnpm >= 10.26.0

Everyday commands:

pnpm install  # install dependencies (one-time setup)
pnpm test     # run unit tests
pnpm tsc -w   # watch for type errors
pnpm verify   # run all checks
pnpm fix      # fix formatting

Releasing

Releases are managed via changesets.

The workflow is:

• Each feature PR must include a changeset file, generated by running pnpm changeset, describing what is in that change and whether a major, minor, or patch version bump is required.
• A GitHub workflow watches the main branch and updates a "Version Packages" PR whenever a feature PR is landed.
• When the "Version Packages" PR is landed, a GitHub workflow updates the package version and changelog based on outstanding changesets, builds a new version of the package, and publishes it to NPM.

Merging the "Version Packages" PR is a manual action (you can use git land for this). The package is built and released automatically when the "Version Packages" PR is merged.