bounce-rate-explanation

bounce-rate-explanation is a skill for Claude Code from mailgun/mailgun-plugins. It costs 31 tokens per session (423 once invoked), scanned A, original, Apache-2.0.

An analysis of why the percentage of failed Mailgun messages, called the bounce rate, has changed. It compares metrics, delivery logs, bounce categories, suppressions, email providers, and list-quality signals.

In plain words
What is it for?
Use it to investigate a high or rising bounce rate for a domain and time window. It helps identify the main drivers and suggest next steps for each category.
Why use it?
It connects the overall rate to specific failure types, providers, recipient groups, or list problems. This helps distinguish temporary delivery issues from invalid addresses or other likely causes.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin.

Part of the mailgun-claude plugin — 15 skills, 7 commands, 1 MCP server shipped together

Good fit Use it to investigate a high or rising bounce rate for a domain and time window. It helps identify the main drivers and suggest next steps for each category.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/mailgun/mailgun-plugins/bounce-rate-explanation
Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent
npx skills add mailgun/mailgun-plugins --skill bounce-rate-explanation
Clone the repo
git clone --depth 1 https://github.com/mailgun/mailgun-plugins

Made for: Claude Code.

Or install mailgun-claude, the plugin that ships this one along with the rest of its 15 skills, 7 commands, 1 MCP server.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for bounce-rate-explanation

README.md
[![agentmods](https://agentmods.dev/badge/skills/mailgun/mailgun-plugins/bounce-rate-explanation/github.svg)](https://agentmods.dev/skills/mailgun/mailgun-plugins/bounce-rate-explanation)
Your own site
<a href="https://agentmods.dev/skills/mailgun/mailgun-plugins/bounce-rate-explanation"><img src="https://agentmods.dev/badge/skills/mailgun/mailgun-plugins/bounce-rate-explanation/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for bounce-rate-explanation

Your own site · 80×15
<a href="https://agentmods.dev/skills/mailgun/mailgun-plugins/bounce-rate-explanation"><img src="https://agentmods.dev/badge/skills/mailgun/mailgun-plugins/bounce-rate-explanation.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 31 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 423 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00031 $0.00423
Opus 5 $0.00015 $0.00211
Sonnet 5 $0.00006 $0.00085
Haiku 4.5 $0.00003 $0.00042

Measured 9d ago against content hash 2286d02b036c, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-09, from the pricing page.

Security

Grade A, and why

bounce-rate-explanation scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 9d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

plugins/mailgun-claude/skills/bounce-rate-explanation/SKILL.md · 42 lines

What it actually says

Bounce Rate Explanation

Use this skill when the user asks why bounce rate is high, why failures increased, which bounce categories are driving a spike, or what list or provider issue may be causing elevated bounces.

Use missing email investigation for one recipient. Use deliverability triage when bounces are only one part of a broader reputation problem.

Intake

Ask for domain, region, time window, comparison window if available, affected segment or tag, and whether the user wants diagnosis only or cleanup guidance.

Workflow

  1. Retrieve metrics for sent volume, permanent failures, temporary failures, hard bounces, complaint rate, and delivery rate.
  2. Compare with a previous similar window when the user provides one or when a sensible baseline can be constructed.
  3. Use bounce classification data to group failures by likely cause.
  4. Review logs for representative SMTP responses and provider concentrated patterns.
  5. Check suppression lists for growth in bounces, complaints, and unsubscribes.
  6. Segment by provider, tag, template, sender identity, or domain when those dimensions are relevant.
  7. Explain the top drivers and recommend category specific next steps.

Common Causes

  • Invalid or stale recipients, typo domains, no MX domains, or purchased lists.
  • Provider throttling or temporary rate limits after sudden volume increases.
  • Authentication or DNS issues that cause policy rejection.
  • Content, link, or template patterns that trigger provider filtering.
  • Suppression effects after previous bounces, complaints, or unsubscribes.

Safety

Do not remove suppressions, add allowlist entries, resend to bounced recipients, import lists, or change sending configuration without explicit confirmation. For cleanup recommendations, explain the reputation risk before any account mutation.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 9d ago First seen · 42 lines · 31 tokens per session scan A 2286d02b036c

Subscribe to this mod's changes

bounce-rate-explanation is a skill published in the GitHub repository mailgun/mailgun-plugins (1 stars, last pushed 19d ago), licensed Apache-2.0. It adds 31 tokens to every session and 423 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

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