Signal-Based Cold Email (2026 benchmarks)

Baseline cold reply rate is ~3.4%. Signal-based emails referencing a funding round, leadership change, or hiring surge hit 15–25% — a ~5x lift. The signal IS the email; without a dated signal, do not draft — return needs_input.

Structure (exactly this order)

1. Hook — why you are writing, tied to the dated signal. Referencing a post they wrote or a job change last month is personalization; mentioning their company name is not.
2. One-sentence value — what you do for someone in their exact situation.
3. One proof point — a single number or named customer. One, not five.
4. Single low-friction CTA — one question or one 15/20-min ask. Never two asks.

Hard rules (Reviewer will reject violations)

• Plain text. 3–5 sentences. Under 150 words.
• Exactly one CTA.
• The signal must be real, dated within 30–90 days, with a source_url in signal_ref.
• Subject line under 50–60 chars, thesis-fit, no clickbait, no ALL CAPS.
• Never send to catch_all / unknown / invalid verification status — only valid or safe_to_send.
• Never contact anyone on the do_not_contact list or already sent at the same sequence_step.
• Prefer a verified public/role inbox scraped from the company site (or founder-provided email). Never invent an address.
• Prioritize recipients by Fit × Intent (high fit + fresh signal first). Personalize from the dated signal and anything verifiable about the person online — relevance beats clever openers.

Follow-up sequencing (real-agency cadence)

• Sequence length 4 emails max (first email captures ~58% of replies; diminishing after 4).
• Cadence: day 0 → day 3 → day 7 → day 14. Set followup_at accordingly when a send completes.
• Each follow-up must add NEW value (new proof point, new angle, or new signal) — never "just bumping this".
• Stop the sequence immediately on reply (replied), bounce (bounced), or unsubscribe request (add to do_not_contact).
• Respect business_rules.max_sends_per_day (default 35/mailbox).

Output

Return a Draft object with subject, body, cta, signal_ref, sequence_step, and a filled self_check (word_count, cta_count, has_signal). Self-check before returning: if any hard rule fails, fix it before handing back.