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    Email Deliverability Doctor (Free Starter)

    1

    Checks subject lines for spam triggers and suggests rewrites. One skill, free.

    Free

    4 usesSecurity scanned
    Email Deliverability Doctor (Free Starter)

    Email Deliverability Doctor (Free Starter)

    Example session with this skill installed

    Subject: "RE: quick question", my first cold email to a marketing director about our analytics tool.

    • Read your context and instructions
    • Compiled the email deliverability doctor

    SUBJECT CHECK, "RE: quick question"
    Risk read: high (pattern-based judgment, not a measurement)
    Flags: fake RE: prefix on a first contact, signals deception to filters and annoys humans; vague "quick question", clickbait gap with no honest preview
    Rewrite 1 (direct): Analytics for [Company]'s marketing team
    Rewrite 2 (curiosity, honest): A question about your campaign reporting
    Honesty check: the original implies a prior thread that doesn't exist, both rewrites represent the email honestly.

    Connects securely to your tools. The creator never sees your data.

    About this skill

    Checks subject lines for spam triggers and suggests rewrites.

    What is inside

    A single SKILL.md you can drop into any compatible agent.

    Use cases

    • Reviewing cold outreach subject lines to remove filter-triggering urgency.
    • Cleaning up newsletter headlines that sound too much like marketing hype.
    • Verifying that a subject line accurately reflects the email body to prevent high bounce rates.
    • Onboarding junior SDRs or marketers to help them understand deliverability best practices.

    Known limitations

    Does not provide numerical spam scores or guarantee inbox placement. It cannot fix deliverability issues caused by poor list quality or improper SPF/DKIM/DMARC setup.

    Full version: Email Deliverability Doctor (Bundle)

    Find more skills like this on the Claude Skills Marketplace, the Codex Skills Marketplace and the Gemini Skills Marketplace, or browse Claude Skills for Marketing & SEO.

    Checks one subject line at a time against common spam-risk patterns, it's a judgment read, not a spam score or an inbox-placement guarantee. List quality and sender setup (SPF/DKIM/DMARC, warm-up) move placement far more, and those live in the paid bundle. It never writes deceptive subjects or fake RE:/FWD: prefixes.

    How to use

    1. 1

      Connect your agent to the Agensi MCP

      Copy the prompt and paste it into Claude, ChatGPT, Cursor or any agent that supports MCP. It sets up the connection for you. Manual setup

    2. 2

      Sign in to Agensi

      Your agent shows a sign-in link. Sign in and click Allow.

    3. 3

      Ask for what you need

      Your agent loads this skill and uses it on your task. It always asks before buying a skill.

    Reviews

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    Security scanned

    Checked by our 8-point scan before listing

    4 uses

    Times used to date

    Free to use

    No account required to browse

    Trust & safety

    Security scan

    Security scan passed 2 months ago

    • Free with an Agensi account

    Permissions

    No special permissions declared or detected

    Listed3 months ago
    Updated6 days ago

    What's inside

    Frequently Asked Questions

    Paste a subject line and it flags common spam-risk patterns, urgency, money language, all-caps, clickbait gaps, misleading RE:/FWD: prefixes, subject-to-content mismatch, explains each in one line, gives a low/moderate/high risk read, and returns two clean rewrites plus an honesty check.

    No. The risk read is a pattern-based judgment, not a spam score or a placement guarantee. Subject lines are the smallest lever, list quality and sender setup move placement far more, and the full bundle covers those. If an email is unsolicited bulk to a non-consenting list, it says plainly that no subject line fixes that.

    As a free gateway skill it follows the open SKILL.md standard and works with any compatible agent, Claude, Cursor, Codex CLI, Gemini CLI, and more. Just paste the subject line and, optionally, one line of context about who it's going to.

    It is a plain SKILL.md file, so it works with agents that read skills, such as Claude Code, Cursor and Codex CLI.

    It checks one subject line at a time against common spam-risk patterns. It gives a judgment read, not a spam score or an inbox guarantee.

    New in Marketing & SEO

    Free