jmap-mcp
Provides a Model Context Protocol (MCP) server exposing tools to interact with JMAP-compliant email servers for email search/retrieval, mailbox listing, message state changes (seen/flagged), moving/deleting messages, and sending/replying to emails. It is implemented in Deno using the @htunnicliff/jmap-jam client library and uses Zod for input validation.
Score Breakdown
⚙ Agent Friendliness
🔒 Security
README states no secrets are logged/exposed and that Zod validates inputs. Authentication relies on a JMAP bearer token provided via environment variables; fine-grained scopes and token lifecycle/rotation are not described. Rate limiting and operational safety (e.g., retry/backoff) are not documented.
⚡ Reliability
Best When
You want an MCP-native interface for email tasks against a JMAP server and can run a Deno stdio MCP server in your agent environment.
Avoid When
You cannot securely manage bearer tokens for the JMAP server or you need explicit, documented rate-limit behavior and retry/idempotency guarantees.
Use Cases
- • Build agent workflows that search and retrieve emails via MCP tools
- • Perform mailbox operations like listing folders and moving/deleting messages
- • Send or reply to emails from an agent with plain-text and/or HTML bodies
- • Extract thread context by fetching threads for given IDs
Not For
- • Directly connecting to non-JMAP email systems that do not support RFC 8620/8621
- • Use cases requiring a public REST/GraphQL API for web clients without running the MCP server
- • Handling high-volume bulk operations without considering provider limits (batch sizes are limited but not rate-limit strategy described)
Interface
Authentication
Authentication is performed by providing a JMAP session URL and a bearer token via environment variables. The README does not describe fine-grained scopes/permissions for the token beyond relying on the JMAP server's auth model.
Pricing
No pricing information is provided; the package appears to be a MIT-licensed open-source MCP server.
Agent Metadata
Known Gotchas
- ⚠ Write actions like send_email and reply_to_email are likely non-idempotent; agents should avoid automatic retries without safeguards.
- ⚠ Bearer token and session URL must be passed via environment variables; missing/expired tokens will cause failures (retry strategy not documented).
- ⚠ Tool batch sizes are capped in the parameter descriptions (e.g., send/retrieve IDs limits), so agents must chunk requests.
Alternatives
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Scores are editorial opinions as of 2026-03-30.