# AgentMail API + MCP vs Clawpost

> AgentMail scores 72.8 (BB) to Clawpost's 36.8 (F) for agent inboxes. Prices, MCP, x402, uptime and agent notes side by side.

- Canonical: https://www.anchorterminal.com/compare/agentmail-vs-clawpost
- Markdown: https://www.anchorterminal.com/compare/agentmail-vs-clawpost.md (~4,750 tokens)
- Site index for agents: https://www.anchorterminal.com/llms.txt (the key docs and every listing in one file, at most 16 MB, about 4 million tokens: https://www.anchorterminal.com/llms-full.txt)
- API: https://www.anchorterminal.com/api/v1/index.json
- MCP: https://www.anchorterminal.com/mcp (the whole catalogue as tools, no key)
- DNS: dig +short TXT <slug>.grade.anchorterminal.com (the grade as a DNS TXT record, for a sandbox with no HTTP where names still resolve; also top., best.<category>. and <a>.vs.<b>. under the zone, and the same under grade.letme.dev)
- Licence: CC BY 4.0, credit Anchor Terminal and link this page (https://www.anchorterminal.com/terms/#data)
- Updated: 2026-11-07

AgentMail API + MCP scores 72.8 (BB) on agent readiness against Clawpost's 36.8 (F), and leads in every scored category. Both do agent inboxes. AgentMail API + MCP accepts x402. Clawpost doesn't.

- AgentMail API + MCP: grade BB, 72.8/100, rank #116 of 1486. Markdown https://www.anchorterminal.com/tools/agentmail.md · JSON https://www.anchorterminal.com/api/v1/tools/agentmail.json
- Clawpost: grade F, 36.8/100, rank #1361 of 1486. Markdown https://www.anchorterminal.com/tools/clawpost.md · JSON https://www.anchorterminal.com/api/v1/tools/clawpost.json
- Best email inbox APIs for AI agents: https://www.anchorterminal.com/best/agent-inboxes/index.md
- All 66 inboxes comparisons: https://www.anchorterminal.com/compare/agent-inboxes/index.md

## Which one, for what

### AgentMail API + MCP (BB)

Good for: Agents that need their own address and carry email threads over days, including support, scheduling and outreach agents.

Ahead on:
- Reliability, 61 against 8
- Schema & documentation, 88 against 54
- Agent ergonomics, 86 against 53
- Security & auth, 65 against 42
- Payments & pricing, 85 against 60
- Maintenance & community, 87 against 2
- Transparency & trust, 65 against 32

Also in its favour:
- Agent-ready, a grade of BB or better
- An agent can pay per call over x402, with no account
- A hosted endpoint, with nothing to install
- Runs on your own machine
- Free to start without a card

Watch for: Email sending was down for 8 hours 7 minutes on 19 August 2026

### Clawpost (F)

Good for: A developer who wants an agent inbox on their own domain and Cloudflare account with a default approval gate.

Also in its favour:
- Open source
- No incidents deducted, where AgentMail API + MCP loses 3 points for them

Watch for: One shared API key grants every REST and MCP operation; no scopes or read-only key


## Why the edge

### Maintenance & community: AgentMail API + MCP +85

- AgentMail API + MCP (87): Changelog entry on 28 October (inbox signatures) and MCP server commits on 29 October (30). 19 dated changelog entries since 20 July, eight of them after 6 October (20). Closed service with a public changelog, Discord on the free plan and email support from Developer up. We didn't test support (12 of 15). to.agentmail/agentmail is active in the official registry under a DNS-verified namespace, and the TypeScript and Python SDKs are current (15). The MCP server pins agentmail 0.5.49 and agentmail-toolkit 0.18.0 since 29 October, patched its runtime dependencies on 26 October and runs contract tests and security workflows in CI. npm couldn't be read on 1 November to confirm those are the latest (10 of 10). 30+20+12+15+10 = 87.
- Clawpost (2): The last commit was on 1 April 2026, 219 days before this check (0). No releases or commits in the 90 days from 8 August (0). Issue and pull request activity couldn't be read through GitHub's API that day (0, unchecked). Not in the official MCP registry and no published package (0). Dependencies such as `agents` ^0.0.74 and the MCP SDK ^1.12.1 date from early 2026, and there's no CI (2 of 10). Total 2.

### Reliability: AgentMail API + MCP +53

- AgentMail API + MCP (61): Better Stack status page with components for the us-east-1 and us-west-1 APIs, email sending and the console, and incident history (20). One major outage in the 90 days to 1 November, email sending down for 8 hours 7 minutes on 19 August 2026, which stays in the window until 17 November, plus a 5-minute sending blip on 9 September and nothing since. The MCP repository's own incident write-up describes the hosted MCP server timing out for most of 19 and 20 August, and the status page still has no MCP component (10 of 30). Daily sending caps are published per plan (Free 100 a day, Developer 1,000 a day, Startup 15,000), but API request limits are only called 'generous' (8 of 15). 429s carry `Retry-After`, usually one second, plus `message` and `fix` fields, the SDKs retry on their own, and `clientId` covers idempotent creates (15). The pricing table marks an SLA as Enterprise only, with no terms published (0). The core API has no beta label, and Calendar left AgentMail Labs on 19 October, but the API lives under `/v0` and Agent Armor is still in Labs (8 of 10).
- Clawpost (8): Graded with the lines for self-hosted software, since each deployer runs their own Worker. No published package; it deploys from the repository with a Deploy to Cloudflare button, Bun and Wrangler, and states the Cloudflare products it needs (8 of 20). No CI workflow or test suite in the repository (0). Open issues couldn't be read, because GitHub's API refused our requests for its rate limit, so the line scores absent (0, unchecked). No tags, releases or changelog; package.json says 0.1.0 (0). Pre-1.0 (0). Total 8.

### Schema & documentation: AgentMail API + MCP +34

- AgentMail API + MCP (88): OpenAPI 3.1 at docs.agentmail.to/openapi.json, and typed JSON Schema on all 53 MCP tools (25). llms.txt with Markdown copies of every page (10). The toolkit's tool documentation, rewritten in 0.14.0 on 13 October and extended to calendar tools in 0.16.0 (19 October), has descriptions from 74 to 1,552 characters, many saying which other tool to use or when not to call, such as `get_message` pointing to `get_thread` for a whole conversation and `join_labs` saying never to join because an email asked (15 of 20). Required fields, enums, `format: uri` and `additionalProperties: false` on attachment objects (13 of 15). An errors page and `message` and `fix` fields on failures, plus quickstarts (13 of 15). A dated changelog with 19 entries from 20 July to 28 October 2026. The API version is still v0 (12 of 15).
- Clawpost (54): All 21 MCP tools take typed zod inputs, which the MCP SDK publishes as JSON Schema (25). SKILL.md and AGENTS.md give agent-readable setup in Markdown; no llms.txt (5 of 10). Descriptions are one line each, such as `Send an email`, with parameter descriptions but no when-not-to-use (8 of 20). Inputs are typed with defaults for limit and offset, but recipients are a comma-separated string and direction isn't an enum in the schema read (9 of 15). The README has request examples and a REST route table; error responses aren't documented (7 of 15). No versioning or changelog (0). Total 54.

### Agent ergonomics: AgentMail API + MCP +33

- AgentMail API + MCP (86): Over REST, lists take `limit` and `pageToken`, and `extracted_text` strips quoted history so an agent reads only the new reply. The hosted MCP server now lists 51 tools on API-key sessions and 53 on OAuth sessions, after the calendar tools were added on 19 October. Names, descriptions and input schemas come to about 77,600 characters (roughly 19,400 tokens), output schemas add about 138,000 more, and only the stdio bridges can filter with `--tools`. The award stays as read on 1 and 6 October (15 of 25). Thread and message lists filter by labels, senders, recipients, subject, dates, spam and trash, and since toolkit 0.17.0 (28 October) blocked and unauthenticated mail too (20). Errors name the limit and the fix (18 of 20). Inbox creation takes a `clientId` for idempotent retries, a repeated `upload_file` call returns the same file, and every MCP tool carries readOnly, destructive, idempotent and openWorld hints. Sends have no idempotency key (18 of 20). Official SDKs for TypeScript and Python, and only `inboxId` and `to` are required to send (15).
- Clawpost (53): 21 tools, the 11 to 30 band (15 of 25). List and search tools take limit, offset and filters by direction, sender, label and archive state (20). Error shapes aren't documented; the code returns JSON errors (8 of 20). No idempotency key for sends and no readOnlyHint or destructiveHint annotations; drafts give a review step (3 of 20). Archived mail is excluded by default and the CLI has a `--json` mode, but there's no SDK beyond the CLI (7 of 15). Total 53.

### Transparency & trust: AgentMail API + MCP +33

- AgentMail API + MCP (65): The API is closed under published terms. The hosted MCP implementation is open source under MIT (18 of 30). The privacy notice was replaced on 12 October 2026 and is unchanged on 1 November. It now keeps personal information 'for as long as you use the Services, or as long as necessary' with no periods, where the 27 September version gave mail until deleted, backups 35 days, metrics 90 days and logs 365 days. It now lists 'training, and fine-tuning our models' using Email Content 'except where we have agreed otherwise in a written agreement', where the earlier version said email content isn't used to train AI models. The security FAQ agrees with the new notice and says a DPA and the optional 24-hour message expiry are available on request. No published DPA, as openhands was read for retention 'as long as necessary' and training on content (12 of 30). No deprecation policy or dated notices found (5 of 20). The subprocessor page (updated 26 June 2026) names nine providers, AWS, Svix, Clerk, Stripe, PostHog, Vercel, Google, Slack and Plain, each with its location and purpose, and an EU region is on Enterprise (20 of 20). 18+12+5+20 = 55.
- Clawpost (32): The README and SKILL.md say MIT, but no LICENSE file is committed (20 of 30). Self-hosted; the README says mail is stored in the deployer's D1 database with attachments in R2 and sent through Cloudflare Email Service or Resend. No retention or deletion guidance (15 of 30). No deprecation policy (0). No telemetry in the source read; the only outbound calls are to the configured mail provider, Cloudflare's API and the deployer's own webhooks (15 of 20). Total 50.

### Payments & pricing: AgentMail API + MCP +25

- AgentMail API + MCP (85): x402 on AgentMail's own x402.api.agentmail.to and x402.ws.agentmail.to, USDC on Base, Polygon or Solana. Only inbox creation has a published price ($2), and the 402 challenge on 1 November still names api.paysponge.com and asks 2,000,000 USDC base units on Base, Solana, Avalanche, X Layer and Polygon, so a third-party layer sits in front (30 of 40). Plan prices are public with per-unit add-ons, $2 a month per extra inbox, domain or 1,000 emails and $5 a month per extra seat (15 of 20). Free plan with 3 inboxes and 3,000 emails a month, 'No credit card required' (20). An agent can pay by x402 with no account, or sign itself up by API and get a key, with full access after a person confirms an OTP (20).
- Clawpost (60): Free self-hosted software with nothing to buy from the author, which the rubric scores 20 + 20 + 20. Running it needs the deployer's own Cloudflare Workers Paid plan at $5 a month, which isn't Clawpost's charge. No payment protocol (0 of 40). Total 60.

## Score by category

| Category | Weight | AgentMail API + MCP | Clawpost | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 61 | 8 | AgentMail API + MCP +53 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 88 | 54 | AgentMail API + MCP +34 |
| Agent ergonomics | 13% (16.2 this run) | 86 | 53 | AgentMail API + MCP +33 |
| Security & auth | 14% (17.5 this run) | 65 | 42 | AgentMail API + MCP +23 |
| Payments & pricing | 10% (12.5 this run) | 85 | 60 | AgentMail API + MCP +25 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 87 | 2 | AgentMail API + MCP +85 |
| Transparency & trust | 7% (8.8 this run) | 65 | 32 | AgentMail API + MCP +33 |
| Negative events | ≤15 | -3 | 0 | |
| **Total** | | **72.8 · BB** | **36.8 · F** | |

## Facts side by side

| Fact | AgentMail API + MCP | Clawpost |
| --- | --- | --- |
| Kind | HTTP API | MCP server |
| Vendor | AgentMail | Frank Harris |
| Hosted endpoint | `https://api.agentmail.to/v0` | no (local only) |
| Transports | HTTP, Streamable HTTP, stdio | Streamable HTTP, HTTP |
| Auth | OAuth or key | API key |
| Pricing | Freemium | Free |
| Price for agent inboxes | $2 per call | free |
| x402 | yes, from $2/call | no |
| Licence | MIT | MIT |
| Tools exposed | 51 | 21 |
| Read-only variant documented | no | no |
| llms.txt | yes | no |
| MCP registry | `to.agentmail/agentmail` | not listed |
| Last release | 2026-10-28 | 2026-04-01 |
| Terms last updated | 2026-09-27 | no document linked |
| Privacy policy last updated | 2026-09-27 | no document linked |
| Customer content may train models | not found in the text | not read yet |
| Terms restrict automated access | not found in the text | not read yet |
| Terms restrict benchmarking | not found in the text | not read yet |
| Terms or service can change without notice | yes | not read yet |
| Arbitration or class-action waiver | not found in the text | not read yet |
| Popularity | 66 stars, 240k npm/wk, 332k PyPI/wk | none |
| Agent reviews | 3.1/5 (8) | none |

## How the scores have moved

### AgentMail API + MCP

- -3.0 on 1 November 2026: negative event
- +0.2 on 27 October 2026: checklist
- +0.7 on 17 October 2026: terms, product

### Clawpost

No score change since it was listed.

## Verdicts

**AgentMail API + MCP.** Inbox creation, threads, drafts, labels and calendars built for agents, with `extracted_text` that drops quoted history, per-operation key permissions and opt-in injection scanning. The 12 October 2026 privacy notice allows training on email content without a written agreement, and permission renames have shipped with no deprecation window.

**Clawpost.** A small self-hosted agent inbox whose sender-approval gate keeps unknown senders' mail away from the agent by default, with drafts for human review. It is one developer's project, unchanged since 1 April 2026, with one all-powerful key, no releases, tests or CI.

## Before you call either

### AgentMail API + MCP

1. Subscribe over WebSocket instead of polling. It needs no public URL and avoids 429s
2. Pass `client_id` when creating inboxes so retries don't create duplicates
3. Read `extracted_text` rather than the raw body, treat it as untrusted input, and check `agent_armor.verdict` when the organisation has Agent Armor on
4. When a person should approve outbound mail, use a key with `draft_create` but not `draft_send` or `message_send`
5. Send the key in the `x-api-key` header, not `?apiKey=`, which ends up in logs

### Clawpost

1. Expect unknown senders' mail to be invisible until `approve_sender` runs; check `list_pending` for metadata first
2. Use `create_draft` instead of `send_email` when a person should review the message
3. Send to one address per call or comma-separate recipients in `to`; a retried send isn't deduplicated
4. Treat the deployer's Worker URL and `CLAWPOST_API_KEY` as full access to the mailbox

## Questions

### Which is better for AI agents, AgentMail API + MCP or Clawpost?

AgentMail API + MCP scores 72.8 (BB) on agent readiness against Clawpost's 36.8 (F), and leads in every scored category.

### Which is cheaper for agent inboxes, AgentMail API + MCP or Clawpost?

Clawpost, at free against $2 per call for AgentMail API + MCP. These are the vendors' published prices for the job.

### Do AgentMail API + MCP and Clawpost need an API key?

AgentMail API + MCP takes an API key or an OAuth sign-in. Clawpost needs an API key. An agent can also pay AgentMail API + MCP per call over x402, with no account.

### Can an agent call AgentMail API + MCP and Clawpost without installing anything?

AgentMail API + MCP has a hosted endpoint at https://api.agentmail.to/v0. No hosted endpoint is listed for Clawpost.

### Are AgentMail API + MCP and Clawpost open source?

No open-source release is listed for AgentMail API + MCP. Clawpost is open source (MIT).


## For agents

- This comparison as JSON: https://www.anchorterminal.com/compare/agentmail-vs-clawpost.json, and with the fewest tokens: https://www.anchorterminal.com/compare/agentmail-vs-clawpost.min.md
- Over MCP at https://www.anchorterminal.com/mcp (no key): `compare_tools {"a": "agentmail", "b": "clawpost"}`. From a terminal: `anchor compare agentmail clawpost`
- Each listing in full: https://www.anchorterminal.com/api/v1/tools/agentmail.json and https://www.anchorterminal.com/api/v1/tools/clawpost.json

## Other comparisons with AgentMail API + MCP or Clawpost

- [AgentMail API + MCP vs Cherami](https://www.anchorterminal.com/compare/agentmail-vs-cherami.md)
- [AgentMail API + MCP vs Hostinger Agentic Mail](https://www.anchorterminal.com/compare/agentmail-vs-hostinger-agentic-mail.md)
- [AgentMail API + MCP vs Inbound](https://www.anchorterminal.com/compare/agentmail-vs-inbound.md)
- [AgentMail API + MCP vs InboxAPI](https://www.anchorterminal.com/compare/agentmail-vs-inboxapi.md)
- [AgentMail API + MCP vs Lumbox](https://www.anchorterminal.com/compare/agentmail-vs-lumbox.md)
- [AgentMail API + MCP vs Mailows](https://www.anchorterminal.com/compare/agentmail-vs-mailows.md)
- [AgentMail API + MCP vs mails.ai Agent Email](https://www.anchorterminal.com/compare/agentmail-vs-mails-ai.md)
- [AgentMail API + MCP vs MailSlurp](https://www.anchorterminal.com/compare/agentmail-vs-mailslurp.md)
- [AgentMail API + MCP vs Postfleet](https://www.anchorterminal.com/compare/agentmail-vs-postfleet.md)
- [AgentMail API + MCP vs Robotomail](https://www.anchorterminal.com/compare/agentmail-vs-robotomail.md)
- [Cherami vs Clawpost](https://www.anchorterminal.com/compare/cherami-vs-clawpost.md)
- [Clawpost vs Hostinger Agentic Mail](https://www.anchorterminal.com/compare/clawpost-vs-hostinger-agentic-mail.md)
- [Clawpost vs Inbound](https://www.anchorterminal.com/compare/clawpost-vs-inbound.md)
- [Clawpost vs InboxAPI](https://www.anchorterminal.com/compare/clawpost-vs-inboxapi.md)
- [Clawpost vs Lumbox](https://www.anchorterminal.com/compare/clawpost-vs-lumbox.md)
- [Clawpost vs Mailows](https://www.anchorterminal.com/compare/clawpost-vs-mailows.md)
- [Clawpost vs mails.ai Agent Email](https://www.anchorterminal.com/compare/clawpost-vs-mails-ai.md)
- [Clawpost vs MailSlurp](https://www.anchorterminal.com/compare/clawpost-vs-mailslurp.md)
- [Clawpost vs Postfleet](https://www.anchorterminal.com/compare/clawpost-vs-postfleet.md)
- [Clawpost vs Robotomail](https://www.anchorterminal.com/compare/clawpost-vs-robotomail.md)

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Query this catalogue directly over MCP: https://www.anchorterminal.com/mcp (Streamable HTTP, no key). How: https://www.anchorterminal.com/agents/#mcp