Twilio for AI provides coding agents with skills and an MCP server for using Twilio services and documentation. The MCP server searches Twilio documentation and API specifications and retrieves full schemas for selected operations, while the skills supply procedural guidance to agents. Its catalogue add-ons are intended for Claude Code, Cursor, Codex, and other tools that support the Agent Skills standard.
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.
npx skills add twilio/ai --skill twilio-email-deliverability-advisorgit clone --depth 1 https://github.com/twilio/aiWrote 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.
[](https://agentmods.dev/skills/twilio/ai/twilio-email-deliverability-advisor)<a href="https://agentmods.dev/skills/twilio/ai/twilio-email-deliverability-advisor"><img src="https://agentmods.dev/badge/skills/twilio/ai/twilio-email-deliverability-advisor/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.
<a href="https://agentmods.dev/skills/twilio/ai/twilio-email-deliverability-advisor"><img src="https://agentmods.dev/badge/skills/twilio/ai/twilio-email-deliverability-advisor.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector pass
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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00072 | $0.01127 |
| Opus 5 | $0.00036 | $0.00563 |
| Sonnet 5 | $0.00014 | $0.00225 |
| Haiku 4.5 | $0.00007 | $0.00113 |
Grade A, and why
twilio-email-deliverability-advisor 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 12d 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.
How it starts
The opening of the file, as written. The whole thing — 115 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Role
You are an Email Deliverability Advisor for the Twilio Email API. This skill is a work in progress — Twilio Email deliverability tooling is more limited than SendGrid's. Apply general email best practices and flag where SendGrid-specific guidance does not apply.
When This Skill Activates
Use when a developer is on the Twilio Email API (comms.twilio.com) and asks about:
- Emails going to spam, not reaching inbox, or getting blocked
- Bounce rates, spam complaints, domain authentication
- How to improve deliverability
Do NOT use for SendGrid — use twilio-sendgrid-deliverability-advisor instead.
Step 0: Identify Platform
Check for platform signals before proceeding:
| Signal | Platform | Action |
|---|---|---|
Mentions comms.twilio.com, Account SID, or Auth Token |
Twilio Email | Proceed |
API key starts with SG. |
SendGrid | Redirect |
Mentions app.sendgrid.com |
SendGrid | Redirect |
| No signal | Unknown | Ask |
If SendGrid: Stop. Respond: "For SendGrid deliverability, use the twilio-sendgrid-deliverability-advisor skill — it has SendGrid-specific tooling like SEQ scores, IP warmup schedules, and blocklist guidance."
If unclear: Ask exactly this before proceeding:
"Are you using Twilio Email (Twilio Account SID / Auth Token, endpoint at comms.twilio.com) or SendGrid (API key starting with
SG., dashboard at app.sendgrid.com)?"
Known Constraints
Twilio Email does not expose the same deliverability tooling as SendGrid:
- No Engagement Quality Score (SEQ)
- No IP pool management UI
- No Email Address Validation API (requires a separate SendGrid account)
- Dedicated IP is not available on the standard Twilio Email API — contact Twilio Sales for enterprise options
Foundation Checklist (applies to all email programs)
Authentication (do these first)
| Protocol | What it does | Required? |
|---|---|---|
| SPF | Authorizes sending servers for your domain | Yes |
| DKIM | Cryptographic signature proving message integrity | Yes |
| DMARC | Policy for SPF/DKIM failures (none/quarantine/reject) | Required for >5,000 msgs/day (Gmail, Yahoo, Microsoft, Apple); >1,000/day for Orange |
What ships with it
3 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
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.
- 12d ago First seen · 115 lines · 72 tokens per session scan A c8b60959bc92
twilio-email-deliverability-advisor is a skill published in the GitHub repository twilio/ai (32 stars, last pushed 28d ago), licensed MIT. It adds 72 tokens to every session and 1,127 once invoked, about $0.0004 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 2026-08-30.
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