mail-mcp-server
mail-mcp-server is a Java/Spring AI MCP Server example that exposes email-related capabilities as MCP tools (notably: find contact email by name, and send an email via Spring Boot’s mail integration). It is intended to be used by an MCP Host/Client (e.g., via Spring AI’s MCP client) to let an LLM trigger these tools.
Score Breakdown
⚙ Agent Friendliness
🔒 Security
TLS enforcement for the MCP transport and SMTP transport is only partially implied (SMTP uses SSL/StartTLS in the sample), but MCP tool access authentication/authorization is not described. Mail sending and contact lookup inputs are not strongly validated in the shown code (risk of unintended sends). Secrets are referenced via Spring configuration placeholders, which is generally better than hardcoding, but there’s no explicit guidance about avoiding logging of sensitive fields beyond basic log statements.
⚡ Reliability
Best When
You want a simple Spring AI MCP Server to connect an agent to basic SMTP email operations in a controlled environment.
Avoid When
You need strong authorization, auditability, and validated input guarantees for arbitrary email sending (the example shows minimal validation and coarse control).
Use Cases
- • Integrating an LLM/agent with enterprise email sending workflows via MCP tool calls
- • Automating drafting/sending emails after contact lookup (name-to-address)
- • Building a local/dev prototype for MCP tool exposure using Spring AI (WebFlux SSE)
Not For
- • Production-grade email dispatch systems without additional security, auditing, validation, and operational hardening
- • Use cases requiring robust contact directory management (the sample uses an in-memory mock map)
- • Environments where sending email must be strictly user-approved and access-controlled at the tool level
Interface
Authentication
The README sample shows SMTP credentials configured via Spring properties, but it does not describe any authentication/authorization for MCP tool access (i.e., who is allowed to call sendMail).
Pricing
No pricing information provided (this appears to be an open-source example).
Agent Metadata
Known Gotchas
- ⚠ No explicit tool-level authorization in the example—agents may be able to trigger email sends if MCP access is exposed.
- ⚠ The contact lookup is based on an in-memory mock map; production agents may produce mismatched or missing contacts unless integrated with a real directory.
- ⚠ Input validation is minimal (e.g., regex-based matching and lack of address validation), so agents should not rely on the tool to sanitize content.
Alternatives
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Scores are editorial opinions as of 2026-04-04.