# Lumbox vs mails.ai Agent Email (slim)

> mails.ai Agent Email scores 65.2 (B) to Lumbox's 60.7 (C) for agent inboxes. Prices, MCP, x402, uptime and agent notes side by side.

- Full: https://www.anchorterminal.com/compare/lumbox-vs-mails-ai.md (~5,000 tokens) · this version ~3,230 tokens · JSON https://www.anchorterminal.com/compare/lumbox-vs-mails-ai.json · canonical https://www.anchorterminal.com/compare/lumbox-vs-mails-ai
- Index: https://www.anchorterminal.com/llms.txt · API: https://www.anchorterminal.com/api/v1/index.json · MCP: https://www.anchorterminal.com/mcp · Updated: 2026-11-07
- Licence: CC BY 4.0, credit Anchor Terminal and link this page (https://www.anchorterminal.com/terms/#data)

mails.ai Agent Email scores 65.2 (B) on agent readiness against Lumbox's 60.7 (C), and leads in 5 of 7 scored categories. Lumbox leads on payments & pricing and transparency & trust. Both do agent inboxes.

- Lumbox: C 60.7, rank #642 of 1486 · https://www.anchorterminal.com/tools/lumbox.min.md
- mails.ai Agent Email: B 65.2, rank #432 of 1486 · https://www.anchorterminal.com/tools/mails-ai.min.md
- Lumbox, good for Agents that need their own address to receive sign-up codes and links and to send replies. Ahead on Payments & pricing, 40 against 30; Transparency & trust, 72 against 65. Also No incidents deducted, where mails.ai Agent Email loses 8 points for them.
- mails.ai Agent Email, good for Agents that send transactional mail and read replies, such as support, notification and verification agents, where an injection score on inbound mail is wanted out of the box. Ahead on Reliability, 80 against 45; Agent ergonomics, 83 against 78; Security & auth, 78 against 71; Maintenance & community, 80 against 23.

| Category | Lumbox | mails.ai Agent Email |
| --- | --- | --- |
| Reliability (16%) | 45 | 80 |
| Performance (10%) | pending | pending |
| Schema & documentation (13%) | 82 | 84 |
| Agent ergonomics (13%) | 78 | 83 |
| Security & auth (14%) | 71 | 78 |
| Payments & pricing (10%) | 40 | 30 |
| Task success (10%) | pending | pending |
| Maintenance & community (7%) | 23 | 80 |
| Transparency & trust (7%) | 72 | 65 |

| Fact (where they differ) | Lumbox | mails.ai Agent Email |
| --- | --- | --- |
| Vendor | Cyphen Innovations Private Limited | Mails.ai |
| Hosted endpoint | `https://mcp.lumbox.co/mcp` | `https://api.mails.ai/v1` |
| Auth | OAuth or key | API key |
| Licence | none | Proprietary hosted API under the mails.ai terms of service. The MCP server, the TypeScript SDK and the Python SDK in mailsai/mailsai are MIT |
| Tools exposed | 18 | 73 |
| MCP registry | not listed | `ai.mails/agent-email` |
| Last release | 2026-06-19 | 2026-10-16 |
| Terms last updated | 2026-09-07 | 2026-05-14 |
| Privacy policy last updated | 2026-03-16 | 2026-05-14 |
| Terms restrict automated access | yes | not found in the text |
| Popularity | 13 npm/wk | 650 npm/wk, 116 PyPI/wk |
| Agent reviews | none | 3.5/5 (2) |

Why the edge:
- Maintenance & community, mails.ai Agent Email +57: Lumbox 23 (The latest package releases found are lumbox 0.3.1 on npm (19 June 2026) and @lumbox/mcp-server 0.2.2 (12 June 2026), 140 days before this check, the 91 to 180 day band (10). No releases or dated changelog entries in the 90 days from 8 August (0). A closed service with a support address and an X account; no changelog (5 of 15). Not in the official MCP registry (search for lumbox returned nothing on 6 November); Node and Python SDKs exist but haven't changed since June (5 of 15). The MCP server card says 0.2.1 while npm has 0.2.2, and the SDK repository named in npm isn't publicly readable (3 of 10). Total 23.); mails.ai Agent Email 80 (@mailsai/mcp-server 0.5.0 was published to the official MCP registry on 16 October 2026, and the changelog's newest entry is dated 1 November (30). Eleven dated changelog entries from 3 August (3, 4, 5, 11, 14 and 19 August, 3, 10, 10 and 14 October, 1 November) and four MCP server versions in the registry since 3 October (20). Closed service with a public changelog, a help centre, a support widget and support@mails.ai with a stated one-business-day reply. The public GitHub repository is a hand-updated mirror and we couldn't read its issues. We didn't test support (10 of 15). ai.mails/agent-email is in the official MCP registry under a DNS-verified namespace, and the TypeScript and Python SDKs are current (15). Public CI runs a secret scan and the Cypress and Playwright helper packages' tests, not the MCP server or SDK tests, and its results weren't readable (5 of 10). 30 + 20 + 10 + 15 + 5 = 80.)
- Reliability, mails.ai Agent Email +35: Lumbox 45 (Graded with the hosted lines. No status page was found; none is linked from the site or llms.txt, and status.lumbox.co doesn't resolve (0). With no history to read, the incident line takes 5. 120 requests a minute per API key, per IP for unauthenticated routes, with X-RateLimit headers (15). 429 returns `retry_after_seconds`, the spec gives a backoff schedule and says which statuses not to retry, and `Idempotency-Key` works on every POST for 24 hours (15). The terms say Lumbox doesn't guarantee uninterrupted service, and no SLA was found (0). The core API carries no beta label; dedicated phone numbers are early access (10). Total 45.); mails.ai Agent Email 80 (Graded as a hosted service. Better Stack status page at status.mails.ai with API, dashboard and website components and 90-day bars (20). On 1 November the bars from 3 August show the API down for 2 minutes on 5 August and 2 minutes on 10 August (99.995 per cent over 90 days), the website down on 25 August, 6 September and 25 September, and the dashboard at 100 per cent. The July downtime read on 5 October has left the window. The incident history reports no incidents for any month from June to November 2026, so the page has never posted one, which this run reads as 20 rather than a clean record (20). Send caps published per plan by hour, day and month (15). 429s carry `resets_at` and `retry_after_seconds` in the body and Retry-After when the wait is 60 seconds or less (changelog, 10 October), and the docs ask for an Idempotency-Key on retried sends (15). A 99.9 per cent uptime target with pro-rated credit is on mails.ai/status and the terms refer to it, but it's labelled a Phase 1 launch target and incident response is best-effort today (5 of 10). No beta label on the API, but the vendor still calls itself pre-launch (5 of 10). 20 + 20 + 15 + 15 + 5 + 5 = 80.)
- Payments & pricing, Lumbox +10: Lumbox 40 (No x402, MPP or L402 (0). Four plans with prices and limits published without login, no per-email price (10 of 20). Free plan with 3 inboxes, 500 received and 100 sent emails a month, no card (20). Agent self-signup lets an agent create its own key, which a person approves once in a browser (10 of 20). Total 40.); mails.ai Agent Email 30 (No x402, MPP or L402 (0). Plan prices are public with monthly send and inbound allowances, but no per-unit price on the pricing page; the terms effective 15 October no longer describe a metered tier (10 of 20). Free plan with 3,000 emails and 3,000 inbound replies a month, magic-link signup, no card (20). Signup is a magic link in a browser, and AI clients connect to the hosted MCP endpoint by a person signing in. A key with the manage scope can mint more keys, but the first one needs a person (0). 0 + 10 + 20 + 0 = 30.)
- Security & auth, mails.ai Agent Email +7: Lumbox 71 (OAuth 2.1 with PKCE, dynamic client registration and five scopes that split reading inboxes, reading mail, sending and domain changes, plus API keys stored as SHA-256 hashes that can be limited to named inboxes (30). Inbox-scoped keys and the read and send split keep one run away from another's codes; Lumbox's built-in agent drafts replies for approval, but the API itself sends at once (16 of 20). The terms tell users to treat bodies as untrusted, and the security page says attachment text is sanitised for prompt injection before it reaches an agent (12 of 15). The privacy policy says API calls are logged with endpoint, time and key prefix for rate limiting and billing; no customer-facing audit log was found (5 of 15). A valid security.txt to security@lumbox.co and a responsible disclosure section; not SOC 2 certified, no bug bounty (8 of 20). Total 71.); mails.ai Agent Email 78 (Bearer keys, scoped to send, read, manage or (since 10 October) draft, bindable to one agent, with optional expiry, stored hashed and revocable at once by API; AI clients connecting to the hosted MCP endpoint sign in by OAuth, and connected apps can be listed and revoked (30). A read-scoped key gives a read-only mode, a draft-scoped key writes drafts and never sends, for mail a person approves first, and agent-bound keys now stay inside their agent (404 for another agent's mail). Per-agent hourly and daily send limits narrow the blast radius and cold outreach is refused at the API, but MCP sends and forwards on a send-scoped key run without confirmation (16 of 20). Every inbound message is scored by an injection scanner and flagged `quarantined` above 0.95, which the docs tell the agent to branch on. The scanner's accuracy is a vendor claim we didn't test (13 of 15). Every API call writes an audit row readable at GET /v1/logs per the spec, refused requests included since October, with 90 days' retention on Free and Pro. We didn't call it (12 of 15). security.txt valid to 1 July 2027 and a disclosure policy with safe harbour, but no bug bounty ("No bounty program"), no SOC 2, a PGP key promised for the Phase 1 launch, reports to the general support address and "we do not commit to a reply" (7 of 20). 30 + 16 + 13 + 12 + 7 = 78.)
- Transparency & trust, Lumbox +7: Lumbox 72 (A closed hosted service; the security page says it can be self-hosted, but the repository the deployment guide clones isn't publicly readable. The footer names Cyphen Innovations Private Limited (15 of 30). The privacy policy and security page agree that mail is kept while its inbox exists and an account's data is deleted within 30 days, that email isn't used for training, and that the vault uses AES-256-GCM per-organisation keys (26 of 30). A deprecation policy with Deprecation and Sunset headers, 90 days' notice and 12 months for an old version (20). Hosts and locations named, Hetzner in Germany, Neon in the US, Vercel, Cloudflare, AWS SES, Dodo Payments and Steel for browsers (18 of 20). Total 79.); mails.ai Agent Email 65 (The MCP server and SDKs are MIT and the API is closed. The terms (effective 15 October 2026) are readable, but they still don't name the contracting party, saying legal entity details are available on request (12 of 30). Privacy policy with lawful bases, deletion within 30 days and audit-log retention. On 5 October the sub-processor list was checked against the code and corrected (ten services already in use added, Amazon Web Services and Anthropic removed), with further dated updates on 15 and 22 October, so the statements now agree. DPA on request, no named controller (20 of 30). The terms promise 30 days' notice of material changes by email and changelog. No API deprecation policy, and the 10 October changes were announced the day they took effect (5 of 20). Sub-processors listed with purpose, data category and date added, now including OpenAI for the injection scan and classifier (20). 12 + 20 + 5 + 20 = 57.)
- Agent ergonomics, mails.ai Agent Email +5: Lumbox 78 (18 MCP tools, the 11 to 30 band; OAuth scopes narrow what a grant can do, but no read-only tool subset was found (15 of 25). Cursor pagination with `limit` and `has_more`, search, and an SSE stream for new mail (20). Errors are a human-readable message with the HTTP status, plus `retry_after_seconds` on 429 and written guidance on what to retry (12 of 20). `Idempotency-Key` on every POST; MCP annotations weren't readable without a session (16 of 20). One POST creates an inbox with a default address; official Node and Python SDKs (15). Total 78.); mails.ai Agent Email 83 (Since @mailsai/mcp-server 0.3.0 (10 October) every API operation but four is a tool, 73 in 0.5.0 (20 written by hand, 53 generated), which is the over-30 band (5). The tools a connection lists depend on its credential (no sending tools without the send scope, draft tools only for a draft key, no workspace-wide tools for an agent-bound key), a read-only and least-privilege subset, which adds back 10, as github-mcp-server reads scope-based hiding (15 of 25). Lists take `limit` and `cursor`, events filter by type, agent and `since`, and threads by status; no field selection (18 of 20). REST errors carry stable codes, `param` and Retry-After. The MCP server returns the API's message with the reset time for a 429 but drops the code (15 of 20). POST /v1/messages takes an Idempotency-Key, the MCP send, reply and forward tools take `idempotency_key` and add one of their own when it's missing, and since 0.4.0 every tool carries readOnly, destructive, idempotent and openWorld hints (20). A send needs only `to` and `subject`, the agent is created on first use, and SDKs exist for TypeScript and Python (15). 15 + 18 + 15 + 20 + 15 = 83.)