agent hallucinated email addresses that all hard-bounced

TL;DR

The agent must only send to addresses that came from a trusted source (your CRM, a form submission, an explicit list) and must never construct or guess an address. Validate every address syntactically before sending, and quarantine anything that fails. Hallucinated addresses hard-bounce, and hard bounces torch your sender reputation fast.

agent hallucinated email addresses that all hard-bounced

Use this when

• sends go to addresses nobody provided
• bounce rates spike after an agent run
• the agent helpfully fills in missing contact info

Not for this skill when

• the list itself is stale (clean the list)
• you need better email copy
• bounces come from full inboxes or blocks (different problem)

Steps

1. Define the allowed address sources (CRM export, signup form, manual list) and reject any address not traceable to one. Verify: every send row names its source.
2. Add a hard rule: the agent never generates, guesses, or completes a partial address. Verify: a test run with missing data skips the row instead of inventing one.
3. Validate syntax on every address before queueing (use a standard validator, not a regex you wrote). Verify: malformed addresses land in quarantine, not in the send queue.
4. In drafts and examples use [recipient email] as the placeholder, never a made-up address. Verify: no example address appears anywhere in templates.
5. Monitor hard-bounce rate per run; pause sending if it crosses 2 percent. Verify: the pause triggers automatically, not by someone noticing.

Tool/version compatibility

Any email sender or CRM. Syntax validation libraries exist in every language; the source-tracing rule is process, not code.

Why it happens

The agent is a completion engine: given a task like contact the marketing lead at Acme, it completes the pattern with a plausible-looking address. Plausible is not real, and mail servers answer with bounces.

Edge cases / pitfalls

• Role addresses like info or support at a domain are real but often unmonitored; decide deliberately whether to send to them.
• Validated syntax is not a validated human; syntax checks catch typos, not fiction. Source tracing is the real guard.
• Never buy or scrape lists to fix coverage; that trades one reputation problem for a worse one.

Variant phrasings

Agent made up email addresses that bounced

Short version: hallucinated recipients.

Sends went to guessed addresses and killed deliverability

Short version: invented addresses hard-bounced.

Provenance

Resolved from the public thread: https://vectle.com/posts/pst_9Az8Vy94yrX4cvAOJlzF7g