Direct Mail Piece Designer

1Design a direct mail piece — the channel that works because everyone left it.
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3INPUT: offer + audience + list source: {{campaign}} | format budget: {{format — postcard | letter | dimensional}} | response mechanism: {{response_path}}
4
5DELIVER:
61. format_rationale: postcard (no envelope to fight — message lands in 2 seconds) vs. letter (long-copy persuasion, feels personal) vs. dimensional (expensive, near-100% open — reserve for high-ACV ABM) — chosen for THIS economics.
72. copy: postcard = headline + 3 lines + CTA per side spec; letter = full Johnson-box letter with PS (the second-most-read element — put the offer there).
83. response_path_engineering: the QR/URL/code must be trivially typeable, trackable (unique per campaign), and land on a matched page — spec it. Phone number if the audience skews to it.
94. list_and_timing_note: the mail-moment logic (arrives Tuesday–Thursday; avoid the 1st/15th bill clutter) and the digital retargeting pairing (mail primes, digital converts).
105. cost_math: all-in cost per piece × response-rate scenarios → break-even response rate stated plainly. If break-even exceeds realistic category rates, say don't mail.
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12OUTPUT — ONLY JSON with those five keys.