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 agentmods add instructions/activecampaign/postmark-mcp/claude-mdgit clone --depth 1 https://github.com/ActiveCampaign/postmark-mcpWrote 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/instructions/activecampaign/postmark-mcp/claude-md)<a href="https://agentmods.dev/instructions/activecampaign/postmark-mcp/claude-md"><img src="https://agentmods.dev/badge/instructions/activecampaign/postmark-mcp/claude-md.svg" alt="Measured on agentmods" height="20"></a>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 | $0.02030 | $0.02030 |
| Opus 5 | $0.01015 | $0.01015 |
| Sonnet 5 | $0.00406 | $0.00406 |
| Haiku 4.5 | $0.00203 | $0.00203 |
Grade A, and why
postmark-mcp CLAUDE.md 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 4d 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 — 74 lines — stays where its author put it; the contents beside it link to each section on GitHub.
CLAUDE.md
This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
Project Overview
Official Postmark MCP (Model Context Protocol) server that enables AI assistants (Claude, Cursor, etc.) to interact with the Postmark email API. Published as @activecampaign/postmark-mcp on NPM.
Commands
- Run server:
npm start(runsnode index.js) - Debug with MCP Inspector:
npm run inspector(launches@modelcontextprotocol/inspector) - Smoke test (read-only):
npm run smoke— runssmoke-test.mjs, which is created from smoke-test.example.mjs. Spawns the server over stdio and exercises every read-only tool against the live Postmark account configured in.env. Does not send mail or mutate state. - Smoke test (mutating):
node smoke-test-mutating.mjs— runs full create→edit→delete lifecycles for templates (including layout binding), webhooks, and suppressions, plus real email sends between two configured verified addresses. Cleans up after itself. Created from smoke-test-mutating.example.mjs; editSENDERandRECIPIENTbefore running. The script refuses to run with the placeholder values still in place. smoke-test.mjsandsmoke-test-mutating.mjsare gitignored. Copy from the*.example.mjscounterparts; this keeps personal verified-sender addresses out of the repo.- No linter is configured.
Architecture
This is a single-file MCP server (index.js) using ES modules ("type": "module"). The structure within index.js:
- Module-level formatting helpers —
fmtInt,fmtPct,fmtPlatformUsage,fmtTopBreakdown,fmtDeliverySummary,fmtStatResponse. Used bygetDeliveryStatsto render polished per-stat output. Keep these pure / dependency-free. initializeServices()— Validates required env vars, verifies connectivity via apostmarkRequest('/server')call, and instantiatesMcpServerfrom@modelcontextprotocol/sdkregisterTools(server)— Registers all 24 MCP tools with Zod schemas for input validation. Each tool wraps apostmarkRequestcall and returns formatted text responsesmain()— Orchestrates initialization, tool registration, and connects toStdioServerTransport
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.
- 4d ago First seen · 74 lines · 2,030 tokens per session scan A aded6c254c06
postmark-mcp CLAUDE.md is an instructions file published in the GitHub repository ActiveCampaign/postmark-mcp (55 stars, last pushed yesterday), licensed MIT. It adds 2,030 tokens to every session, about $0.0102 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.
Other instructions, from other repositories
cli GEMINI.md
Instructions for inboxapi/cli, covering inboxapi cli — gemini agent context, technology stack, commands, cli subcommands and development workflow.
cli AGENTS.md
Instructions for inboxapi/cli, covering cli agent stub, javascript / node.js, mcp protocol, pre-completion checklist and contribution workflow.
cli CLAUDE.md
Instructions for inboxapi/cli: Read ../AGENTS.md for the canonical workflow.
email-templates CLAUDE.md
Instructions for ColorlibHQ/email-templates, covering claude.md, repository purpose, layout, commands and editing or adding a template.
apple-mail-mcp CLAUDE.md
Claude Code instructions for sweetrb/apple-mail-mcp, covering claude.md - apple mail mcp server, configuring imap / smtp (when a user asks to set it up), critical: backslash escaping, why this matters and examples.
cli AGENTS.md
Instructions for nylas/cli, covering ai coding agent guidelines, quick reference: shared helpers, quick reference: adding a new feature and quick reference: credential storage.