Emit Claude Code plugin hint at module load time

[johno-stripe]

Why?

Claude Code supports a plugin hint feature, where if we detect the CLAUDECODE or CLAUDE_CODE_CHILD_SESSION environment variables, emitting the following string will prompt the user to install our official plugin:

<claude-code-hint v="1" type="plugin" value="stripe@claude-plugins-official" />

Our plugin's source code can be found here.

What?

• Sets up a platform function for writing to stderr, void by default, implemented for Node.
• During initialization, checks to see if either variable is set. If so, emits the relevant log line.

Note that while this will fire frequently, Claude Code will automatically hide these log lines and keep the user from being re-prompted:

Claude Code deduplicates by plugin, so emitting on every invocation has no downside (source)

My first approach was to emit this using a post-install script, but npm unfortunately hides the output from the installing process, so those error logs didn't successfully reach Claude.

See Also

Key source here is the documentation on how plugin hints work:

• https://code.claude.com/docs/en/plugin-hints

Changelog

• Emits new Claude Code plugin hint when CLAUDECODE or CLAUDE_CODE_CHILD_SESSION environment variables are detected.