Merge Variable Linter

What it does

An unresolved merge variable is the quietest failure in outbound. It does not raise an error and it does not stop the send. It renders as nothing, leaving a sentence that reads like a bug, and it is only visible after the email has gone. This skill compares the variables used in the copy against the fields present on the rows and reports the gaps before the send rather than after.

When to use it

• check my merge variables
• blank gaps in my sent email
• verify personalization tokens
• about to launch, check the copy
• why is my email missing a word

What it needs from you

• copy: the sequence steps as they will be uploaded
• fields: the field names present on the rows being uploaded
• sample: one real row with values

How it works

1. Extract every variable token from every step, including subject lines, and deduplicate.
2. Compare each against the field list by exact name. Case and separator differences are misses, not matches.
3. For each miss, say whether the fix is renaming the field on the rows or renaming the token in the copy, and pick one so both sides do not get changed at once.
4. Render every step against the sample row and read the result as a sentence. A variable that resolves to an empty string still leaves broken grammar.
5. Check fallbacks: every variable needs one, and the fallback must read naturally in the sentence rather than as a bracketed placeholder.
6. Report the count of variables used, matched, missing, and without a fallback.

What you get back

A variable table with used, matched, fallback present, and the rendered sample. Plus a go or no go line.

The quality bar

• Matching is by exact name, and near matches are reported as misses
• Every step is rendered against a real row, subject lines included
• The report gives a single go or no go verdict
• Fallbacks are checked for grammar, not just for presence

Where it runs

• Claude Code
• Codex CLI
• Cursor
• MCP-compatible agents