Loading skill
Install any skill in seconds. Free to start, no credit card required.
Get Started Free →chunkydotdev/inbox-placement
Understand what determines inbox vs spam placement.
Passed 24 of 24 test cases with the skill, and 17 of 24 without it.
and 4 more in the full report
7 fixed17 passed either way0 still failing0 broke
Tokens, turns and time describe resource use, not a dollar price.
One of 7 test cases the skill fixed. Same model, same prompt, with and without the skill.
An enterprise sender sending high volume to Outlook.com and Hotmail users wants to know Microsoft's updated requirements effective May 2025 regarding sender identity and authentication policies. What minimum DMARC policy is required and what rule applies to From/Reply-To addresses?
| Checked | Without skill | With skill |
|---|---|---|
| Identifies DMARC with at least p=none as required by Microsoft for high-volume senders. | Passed | Passed |
| States that From and Reply-To addresses must be valid addresses capable of receiving replies. | Missed | Passed |
The instructions your model reads when the skill loads.
Understand the factors that determine whether your email lands in the inbox, spam folder, or a secondary tab - and how to control them.
domain-authentication - SPF, DKIM, DMARC setup (a prerequisite for inbox placement)sender-reputation - building and monitoring the reputation signals that drive placementemail-warmup - ramping volume on new domains/IPs to establish reputationspam-filter-avoidance - deep dive on content patterns that trigger filtersbounce-handling - managing bounces that degrade your placement over timesuppression-lists - keeping your list clean to protect engagement metricsInbox placement is the outcome of a scoring system. Every major mailbox provider runs incoming email through a multi-signal classifier that produces a disposition: inbox, spam, or a category tab (Gmail Promotions, Outlook Other). The classifier weighs several signal categories, and their relative importance has shifted significantly since 2023.
Here is the rough weighting that major providers apply, from most to least influential:
| Signal | Weight | What it means |
|---|---|---|
| Sender reputation | ~40% | Domain and IP history, complaint rates, bounce rates |
| Engagement signals | ~25% | Opens, clicks, replies, deletes, moves-to-spam per recipient |
| Authentication | ~15% | SPF/DKIM/DMARC pass/fail, alignment |
| Content analysis | ~10% | Spam phrases, formatting, link patterns, HTML quality |
| Infrastructure | ~10% | IP age, domain age, DNS configuration, TLS |
test cases passed, vs 17 / 24 without
More skills from the same source and nearby in the registry, with their headline benchmark lift.