Borrowing it
Nothing to install: this file belongs to pijusz/mcp-mailtrap. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/pijusz/mcp-mailtrap/master/CLAUDE.mdgit clone --depth 1 https://github.com/pijusz/mcp-mailtrapWrote 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/pijusz/mcp-mailtrap/claude-md)<a href="https://agentmods.dev/instructions/pijusz/mcp-mailtrap/claude-md"><img src="https://agentmods.dev/badge/instructions/pijusz/mcp-mailtrap/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 5.1 | $0.00388 | $0.00388 |
| Opus 5 | $0.00194 | $0.00194 |
| Sonnet 5 | $0.00078 | $0.00078 |
| Haiku 4.5 | $0.00039 | $0.00039 |
Grade A, and why
mcp-mailtrap 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 8d 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.
What it actually says
mcp-mailtrap
MCP server for the Mailtrap email platform. Analytics-first with full CRUD.
Quick Reference
- Runtime: Bun (dev) / Node (built)
- Entry:
src/index.ts - Build:
bun run build→ binary;bun run build:npm→dist/index.js - Test:
bun test - Lint:
biome check src/
Architecture
- Single unified API client routes to 4 Mailtrap base URLs automatically
- All tools return
{ content: [{ type: "text", text }] }MCP format fetchWithRetryhandles 429/5xx with exponential backoff- Account ID resolved lazily on first tool call (env var → auto-discover)
- 4 base URLs: mailtrap.io (general), send.api (transactional), bulk.api (bulk), sandbox.api (sandbox)
Key Patterns
- Tool files export
registerXTools(server: McpServer)functions - Zod for parameter validation
- formatTable for analytics output (Metric | Count | Rate %)
- react-email renders component files (.tsx/.jsx/.js/.mjs) to HTML (not arbitrary strings)
- SMTP credentials redacted in sandbox inbox responses
- Multi-action tools use
actionparam to consolidate CRUD operations
Adding New Tools
- Add tool in appropriate file under
src/tools/ - Use
server.tool(name, description, zodSchema, handler) - Use
request<T>()from mailtrap-api service - Use
resolveAccountId()for account-scoped endpoints - Format output with
formatTable()orJSON.stringify(data, null, 2) - Return
{ content: [{ type: "text" as const, text }] } - Register in
src/tools/index.ts
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.
- 8d ago First seen · 39 lines · 388 tokens per session scan A d9a58bf9688a
mcp-mailtrap CLAUDE.md is an instructions file published in the GitHub repository pijusz/mcp-mailtrap (3 stars, last pushed 4mo ago), licensed MIT. It adds 388 tokens to every session, about $0.0019 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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