subject_line_scorer

com.moltlinestudio/outbound · Verify this server

Score and rank up to 20 email subject lines, best first. FREE. Scores 0-100 on length, spam triggers, caps, personalization merge fields, and curiosity cues. Typical input {"subjects": ["Quick question about {{company}}", "ACT NOW!!!"]} returns {"ranked": [{"subject": ..., "score": 92, "notes": ["personalized (+)", "question format"]}, ...]}. Use when several subject lines need ranking against deliverability and curiosity signals. Not for article headlines, which the creator server's headline_analyzer ranks, and not for message bodies (audit_copy). Errors: on invalid, missing, or malformed input this tool never raises a protocol error — it returns {"error": "<what is wrong and how to fix it>"}. Every call is read-only and idempotent, so after correcting the input it is always safe to retry.