# Deliverability Monitoring

> >-

- **Type:** Skill
- **Install:** `agentstack add skill-leadmagic-gtm-skills-deliverability-monitoring`
- **Verified:** Yes — security-reviewed for prompt injection and unsafe behavior
- **Seller:** [LeadMagic](https://agentstack.voostack.com/s/leadmagic)
- **Installs:** 0
- **Category:** [Communication](https://agentstack.voostack.com/c/communication)
- **Latest version:** 0.1.0
- **License:** MIT
- **Upstream author:** [LeadMagic](https://github.com/LeadMagic)
- **Source:** https://github.com/LeadMagic/gtm-skills/tree/main/skills/analytics/deliverability-monitoring
- **Website:** https://github.com/LeadMagic/gtm-skills

## Install

```sh
agentstack add skill-leadmagic-gtm-skills-deliverability-monitoring
```

Requires the [AgentStack CLI](https://agentstack.voostack.com/docs/cli). Works with Claude Code, Cursor, and any MCP-compatible agent.

## About

# Deliverability Monitoring

## Overview

Deliverability Monitoring provides continuous surveillance of email infrastructure health — the foundation on which all outbound GTM rests. The core principle is that deliverability problems compound silently: by the time you notice lower reply rates, reputation damage may already be weeks deep and require months to repair. This skill prevents the catastrophic mistake of discovering deliverability issues through pipeline decline rather than proactive monitoring.

The non-obvious rule: deliverability is not binary (delivered vs bounced). It exists on a spectrum — inbox vs spam folder vs promotions tab vs graymail vs blocked. A "delivered" email that lands in the spam folder is effectively undelivered. This skill measures inbox placement, not just delivery status.

This skill produces a Domain Health Dashboard with: real-time bounce tracking across all sending domains, spam placement rates by mailbox provider, blacklist status across 50+ blacklists, DMARC aggregate report analysis with forwarding source identification, authentication health scores (SPF/DKIM/DMARC), and predictive reputation trend alerts.

## When to Use

- User says "check my deliverability" or "domain health check" → activate this skill
- User mentions "bounce rate is high" or "emails going to spam" → use this skill for diagnosis
- User asks "is my domain blacklisted" or "blacklist check" → activate monitoring module
- User says "DMARC reports" or "who is sending as my domain" → run DMARC analysis
- User mentions "spam placement" or "inbox rate" → track placement by provider
- User asks "domain reputation" or "sender score" → check reputation scores
- Trigger phrases: email deliverability, bounce tracking, spam folder, sender reputation, email authentication, DKIM SPF, domain warming, inbox placement test

Do NOT use for:
- Setting up DNS authentication initially → use domain-infrastructure
- Writing email content to avoid spam filters → use cold-email-copywriting
- Campaign performance analysis (opens, replies, meetings) → use campaign-analytics
- Choosing or configuring sending platforms → use sending-platforms
- Sequence design or cadence → use cold-email-strategy

## Authoritative Foundations

This skill draws from the following established methodologies:

- **M3AAWG (Messaging, Malware, Mobile Anti-Abuse Working Group)** — Industry best practices for email deliverability. M3AAWG publishes the authoritative guidance on complaint thresholds, authentication requirements, and sender reputation management that major mailbox providers (Google, Microsoft, Yahoo) implement.

- **Google Postmaster Tools** — Official Gmail deliverability data including IP reputation, domain reputation, spam rate, authentication status, and delivery errors. Google's February 2024 sender requirements (mandatory SPF/DKIM/DMARC, = 1024 bits (2048 recommended)
   - Confirm selector matches what sending platform publishes
   - Check for expired or misconfigured keys
   - Multiple sending platforms require multiple DKIM selectors — ensure no conflicts

3. **DMARC Check**:
   - Query DMARC record: `dig TXT _dmarc.domain.com`
   - Verify policy: `p=none` (monitoring only), `p=quarantine` (partial enforcement), or `p=reject` (full enforcement)
   - Check `rua` tag is present for aggregate report delivery
   - Verify `ruf` tag for forensic reports (optional but useful)
   - Check `pct` tag if gradual enforcement is in use
   - Validate alignment mode: `adkim=r` vs `adkim=s` (strict recommended), `aspf=r` vs `aspf=s`

4. **BIMI Check** (optional, for brand display):
   - Query BIMI record: `dig TXT default._bimi.domain.com`
   - Verify VMC (Verified Mark Certificate) if logo display desired

5. **DNS propagation check**: Verify all records resolve from multiple geographic locations using a tool like `dig +trace` or MXToolbox DNS check.

### Phase 3: Bounce Rate Analysis

Analyze bounce patterns to identify root causes:

1. **Export bounce data** from sending platform: date, recipient email, bounce type (hard/soft/block), bounce reason/code, sending domain, sending mailbox, campaign/sequence.

2. **Categorize bounces** by type:
   - **Hard bounces (5xx codes)**: Mailbox doesn't exist (550), domain doesn't exist (NXDOMAIN), user unknown (551), mailbox full and no longer accepting (552). These are permanent failures.
   - **Soft bounces (4xx codes)**: Mailbox full (temporary), server temporarily unavailable (450/451), connection timed out, greylisting, rate limiting. These are transient.
   - **Blocks**: Connection refused (554), spam content detected, IP/domain on blocklist, policy rejection. These indicate reputation problems.
   - **Spam complaints**: Not a bounce but tracked via feedback loops (FBL). If platform provides complaint data, track separately.

3. **Calculate bounce metrics**:
   - Overall bounce rate: total bounces ÷ total sent
   - Hard bounce rate: hard bounces ÷ total sent (target: 100/day

2. **Google Postmaster Tools analysis**:
   - Check Spam Rate graph: must stay below 0.1% (Google threshold is 0.3% but target below 0.1%)
   - Check Domain Reputation: should be "High" or "Medium" — "Low" or "Bad" indicates critical problems
   - Check IP Reputation if using dedicated IPs
   - Check Authentication: DKIM and SPF should show "PASS" for all traffic
   - Check Delivery Errors: identify specific error types and volumes
   - Check Encryption: TLS should be 95%+

3. **Microsoft SNDS analysis**:
   - Check complaint rate per IP
   - Check spam trap hit rate
   - Check delivery status breakdown
   - Microsoft is typically stricter than Google on unknown senders — new domains often face temporary blocking

4. **Engagement-based placement signals** (proxy when seed testing unavailable):
   - Open rate by provider: Gmail 50 emails/day. Weekly for low-volume or paused domains.

3. **Delisting procedures** for common blacklists:
   - **Spamhaus**: Use their Blocklist Removal Center. Requires identifying and fixing the root cause. Delisting is typically automatic within 24 hours once the cause is resolved (no more spam trap hits, no more listings on other criteria).
   - **Barracuda**: Submit removal request via their form. Requires explanation of corrective actions. Manual review, 24-72 hours.
   - **SpamCop**: Listings expire automatically within 24-48 hours of last reported spam. No manual removal. Must stop the spam reports.
   - **UCEPROTECT**: Level 1 expires automatically. Level 2 and 3 require payment for express delisting or wait period (up to 7 days for Level 2).
   - **Microsoft (internal blocklist)**: Not a public blacklist. Submit delisting request via Microsoft's delist portal. Requires JMRP enrollment. Manual review, 24-48 hours.

4. **Blacklist prevention checklist** (verify when addressing any blacklisting):
   - Are all lists verified before sending? (Bounce rate 95% pass rate. Below 90% indicates authentication problems.
   - Identify the source of failures: DKIM failures (signing issue), SPF failures (envelope-from mismatch), or alignment failures (header-from mismatch with authenticated domain)

5. **Spoofing and abuse detection**:
   - Large volume from unknown IPs → likely spoofing or phishing
   - Emails from IPs in unexpected countries → investigate
   - Consistent failures from a legitimate sending service → misconfiguration, fix immediately
   - High count from a single unknown source → targeted spoofing attack

6. **Forwarding analysis** (common DMARC challenge):
   - Emails forwarded by mailing lists or forwarding services often fail SPF (envelope-from changes)
   - High SPF failure rate with DKIM pass → forwarding issue, not spoofing. Consider ARC (Authenticated Received Chain).
   - If forwarding breaks legitimate email flow, adjust DMARC policy carefully (don't jump to p=reject if mailing lists are critical).

### Phase 7: Domain Health Dashboard Construction

Build a consolidated dashboard with all deliverability signals:

1. **Overall Health Score** (0-100):
   - Bounce rate: subtract from 100 (0% = +25 points, 5%+ = 0 points)
   - Spam complaint rate: 0% = +25 points, 0.3%+ = 0 points
   - Blacklist status: clean = +20 points, 1 blacklist = +10, 2+ = 0
   - Authentication: all three pass = +20, DKIM/SPF pass only = +10, failures = 0
   - Inbox placement: >95% = +10, 80-95% = +5, 2x running average → possible blacklisting

5. **Weekly Deliverability Report** format:
   - Executive summary: overall health score and trend
   - Per-domain metrics table
   - Blacklist status table (all domains, all major blacklists)
   - Alert summary (new alerts this week, resolved alerts)
   - Action items for the upcoming week

## Output Format

The agent should produce output in this structure:

```markdown
# Domain Health Dashboard

## Executive Summary
- Overall Health Score: [0-100] ([Critical/At Risk/Healthy/Excellent])
- Trend: [Improving/Stable/Declining] vs last week
- Active Issues: [count] requiring immediate attention
- Top Risk: [specific domain/threat]

## Authentication Status
| Domain | SPF | DKIM | DMARC | Policy | BIMI | Status |
|--------|-----|------|-------|--------|------|--------|
| domain1.com | PASS | PASS | PASS | p=none | - | ✅ |
| domain2.com | FAIL | PASS | FAIL | - | - | ❌ |

## Bounce Analysis
| Domain | 7-Day Bounce% | 30-Day Bounce% | Trend | Hard% | Soft% | Block% |
|--------|---------------|----------------|-------|-------|-------|--------|
| ... | ... | ... | ... | ... | ... | ... |

## Spam Placement
| Mailbox Provider | Inbox% | Spam% | Missing% | Trend | Samples |
|-----------------|--------|-------|----------|-------|---------|
| Gmail | 92% | 6% | 2% | ↓ | 100 |
| Outlook | 78% | 18% | 4% | ↓ | 85 |
| Yahoo | 95% | 3% | 2% | → | 40 |

## Blacklist Status
| Domain/IP | Blacklist | Listed Date | Status | Delisting ETA |
|-----------|-----------|-------------|--------|---------------|
| ip.1.2.3 | Spamhaus SBL | 2024-06-01 | ACTIVE | Under review |
| domain2.com | Barracuda | - | CLEAN | - |

## DMARC Analysis
- Reporting Period: [date range]
- Total Emails Processed: [count]
- DMARC Pass Rate: [%]
- Unknown Senders Detected: [count]
- Spoofing Attempts: [count]

## Alerts (Last 7 Days)
| Severity | Date | Domain | Alert | Status |
|----------|------|--------|-------|--------|
| CRITICAL | 06-05 | domain2 | Bounce rate exceeded 5% | Investigating |
| WARNING | 06-04 | domain1 | Spam rate 0.15% | Monitoring |

## Action Items
1. [Priority 1 action]
2. [Priority 2 action]
...

## Trend Charts (30/60/90 Day)
[Describe key trend observations]
```

## Quality Check

Before delivering, verify:

- [ ] Have all sending domains been audited for SPF, DKIM, and DMARC?
- [ ] Is bounce data categorized by type (hard, soft, block) and by domain/provider?
- [ ] Have blacklist checks been run against all major blacklists (Spamhaus, Barracuda, SpamCop, etc.)?
- [ ] Is DMARC report analysis identifying unauthorized senders and spoofing?
- [ ] Are alert thresholds clearly defined with specific numeric triggers?
- [ ] Does the dashboard include trend data (not just point-in-time)?
- [ ] Are delisting procedures documented for any active blacklist entries?
- [ ] Would an email deliverability specialist find this monitoring coverage comprehensive?

## Common Pitfalls

1. **Monitoring only bounce rate.** Bounce rate tells you about list quality, not reputation. A domain can have 0% bounce rate and 100% spam placement. Always combine bounce tracking with spam placement testing and blacklist monitoring. Bounce rate is necessary but insufficient.

2. **Ignoring Google Postmaster Tools.** Google delivers to approximately 50% of B2B inboxes. If you're not monitoring Google Postmaster Tools, you're flying blind on half your deliverability. Setup takes 5 minutes (DNS TXT verification). The data is free and authoritative — it comes directly from Google.

3. **Reacting instead of trending.** Blacklistings don't happen instantly — complaint rates rise over days to weeks before listing. Monitoring trends (rising complaints, declining open rates by provider, increasing block rates) lets you intervene before blacklisting occurs. Set trend-based alerts, not just threshold-based ones.

4. **Treating all blacklists equally.** Spamhaus SBL listing will cripple deliverability immediately. A listing on a minor blacklist with few downstream consumers may have zero impact. Prioritize remediation based on blacklist impact, not just listing count. Better to be on 3 minor blacklists than 1 Spamhaus listing.

5. **DMARC `p=reject` without understanding forwarding impact.** Moving to `p=reject` before analyzing forwarding patterns will break legitimate email delivery through mailing lists, forwarding services, and some corporate email forwarding rules. Analyze DMARC reports for at least 30 days at `p=none` before considering stricter policies.

6. **Not isolating cold sending domains.** Using the same domain for cold outreach and transactional email means a reputation hit from cold outreach takes down password resets, invoices, and product notifications. This is the single most common deliverability catastrophe. Always separate sending domains by purpose.

7. **Misdiagnosing low open rates.** Low open rates can be caused by spam placement (invisible to open tracking), image blocking (open pixel doesn't load), Apple Mail Privacy Protection (pre-fetches all images, inflating open rates), or genuinely uninterested recipients. Cross-reference with click rates, reply rates, and seed-list tests to determine actual cause.

## Execution Artifacts

- `references/framework-notes.md` — named frameworks, citation anchors, and operating assumptions
- `templates/output-template.md` — copy-paste deliverable structure for the user
- `scripts/check-output.py` — local checklist validator for required sections
This skill includes lightweight artifacts the agent can load on demand:
Use the artifacts when the user asks for an implementation-ready deliverable, a repeatable workflow, or a quality check rather than generic advice.

## Related Skills

- **domain-infrastructure**: Run first if DNS authentication is incomplete or misconfigured. Handles SPF/DKIM/DMARC setup, secondary domains, and inbox rotation.
- **campaign-analytics**: Run after deliverability is confirmed healthy. Layer 1 of campaign analytics depends on deliverability monitoring output.
- **cold-email-strategy**: Adjust sequence architecture based on deliverability constraints (volume limits, warmup status, domain rotation).
- **sending-platforms**: Platform-specific deliverability features and configurations. Integrate monitoring data with platform settings.
- **contact-verification**: Pre-send verification reduces bounce rates. Feedback loop: deliverability monitoring identifies verification gaps.
- **email-finding**: Poor email finder accuracy causes high bounce rates. Deliverability monitoring closes the loop by measuring actual bounce rates from each data source.

## Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

- **Author:** [LeadMagic](https://github.com/LeadMagic)
- **Source:** [LeadMagic/gtm-skills](https://github.com/LeadMagic/gtm-skills)
- **License:** MIT
- **Homepage:** https://github.com/LeadMagic/gtm-skills

Install and usage instructions live in the source repository linked above.

## Pricing

- **Free** — Free

## Security capabilities

Automated source analysis of v0.1.0 — what this tool can access:

- **Network access:** no
- **Filesystem access:** no
- **Shell / process execution:** no
- **Environment & secrets:** no
- **Dynamic code execution:** no

*"Yes" means the capability is present in the source — more access means more to trust, not that it is unsafe.*


## Versions

- **0.1.0** — security scan: passed — Imported from the upstream source.

## Links

- Listing page: https://agentstack.voostack.com/l/skill-leadmagic-gtm-skills-deliverability-monitoring
- Seller: https://agentstack.voostack.com/s/leadmagic
- Browse the marketplace: https://agentstack.voostack.com/browse

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