Postfleet MCP — Watchlist

MCP100 Assessment

Watchlist / Tracking

Why we’re tracking it

Follow-up value is specific to Postfleet agent inbox and mail operations: Do local API-key tools retain account scope and outbound limits equivalent to the hosted connector?

Reviewed Oct 5, 2026 · Documentation review; complete setup workflow not independently tested

Best fit

Agent-owned email infrastructure with inbound parsing/injection screening, scoped keys, drafts and human-approval sending.

What we know

Postfleet gives agents mailboxes and email send/read/reply tools. Inbound messages can be parsed/classified/extracted and screened for prompt injection. Keys are scoped; some sends return pending approval instead of transmitting immediately.

Maintenance / activity evidence

@postfleet/mcp 0.1.4 published 2026-09-02T16:38:01.588Z

Tracking evidence observed Oct 5, 2026. These dated signals do not establish current maintenance. Reviewed enrichment confidence: high.

Verification gaps / watch-outs

Installation and comprehensive security have not been independently audited.
Mailbox/email/draft authority scoped by key. Writes: Create mailbox/domain state; Send/reply email; Create/update/send/delete drafts.
Scoped bearer key.
Sensitive access: Email content, Recipient/sender data, Extracted message data, Bearer key

External communication plus inbound prompt-injection risk; approval and send lists are material controls.

Full authority, access and evidence limits are available in Review context and Access & risk.

All limitations / Review context

Do local API-key tools retain account scope and outbound limits equivalent to the hosted connector?

The bounded review of the publisher's documented Postfleet agent inbox and mail operations and release notices identified no disclosed material condition preventing an accurately scoped public tracking entry. The resource's operational permissions remain uncertainty; this assessment does not certify installation safety.

External communication plus inbound prompt-injection risk; approval and send lists are material controls.
Mailbox/email/draft authority scoped by key.
Scoped bearer key.
Email bodies, inbound messages and extracted structured data are processed by Postfleet; webhooks are signed.
Reviewed write actions: Create mailbox/domain state; Send/reply email; Create/update/send/delete drafts
Sensitive access: Email content, Recipient/sender data, Extracted message data, Bearer key
Installation, client compatibility and comprehensive security have not been independently audited. Authentication and access depend on the configured services.
Runtime behavior, dependencies and undisclosed vulnerabilities were not independently audited.
Documented tool authority and any remote data handling must be checked before installation or use.
Tool inventory, client matrix and permissions completeness were not requirements for this Radar tracking review.
Email can contact real people.
Pending-approval response is not a failure and must not be blindly retried.
Inbound webhook delivery is at-least-once and needs event dedupe/signature verification.
Control-plane key creation/revocation is separate from data-plane MCP.

Original activity observations

@postfleet/mcp 0.1.4 published 2026-09-02T16:38:01.588Z

Technical identity

npm/@postfleet/mcp

Exact implementation source: https://www.npmjs.com/package/@postfleet/mcp ↗
Reviewed resource type: MCP Server
Package identity: npm:@postfleet/mcp
Service endpoint: https://api.postfleet.ai/api/mcp

Evidence & Sources

Evidence basis: Recorded source evidence
Setup runtime verification: Not independently runtime-tested by MCP100 for this setup workflow.

Reviewed Oct 5, 2026 · Latest source observation Oct 8, 2026

Package registry metadata ↗
@postfleet/mcp
Recorded package identity, distribution or download evidence.
Evidence source ↗
postfleet.ai/
Source material retained for this review.
Includes references whose attribution is not established.
Evidence source ↗
postfleet.ai/docs
Source material retained for this review.
Includes references whose attribution is not established.
Evidence source ↗
postfleet.ai/docs/quickstart
Source material retained for this review.
Includes references whose attribution is not established.

Setup · Watchlist

Install & Agents

Publisher instructions.

Source evidence observed Oct 14, 2026.

Additional setup details required — see the specific gaps below.

Install / connect
Publisher instructions
POSTFLEET_API_KEY needed; alternative hosted https://api.postfleet.ai/api/mcp with bearer header.
publisher install or stdio launch · Publisher instructions
npx -y @postfleet/mcp
Configure / authenticate
MCP100 setup guide
Postfleet local stdio uses POSTFLEET_API_KEY; optional hosted endpoint uses HTTP Authorization Bearer.
claude desktop or cursor mcpServers json · MCP100 composed guide
{ "mcpServers": { "postfleet": { "args": [ "-y", "@postfleet/mcp" ], "command": "npx", "env": { "POSTFLEET_API_KEY": "pf_REPLACE" } } } }
Check connection
Suggested check
After POSTFLEET_API_KEY configure, list authorized tools and fetch read-only post information; do not schedule or publish.
Remove / uninstall / revoke
MCP100 setup guide
If you added this integration to Claude Code under the registration name `postfleet`, run `claude mcp remove postfleet` to unregister that client entry. In Claude Desktop, Cursor, VS Code or another host, delete/disable the corresponding named MCP registration in that host's settings and restart/reconnect. If you installed an npm package globally or operate a separate HTTP server, uninstall/stop it with its original deployment method. This does not delete user data or revoke service credentials.
MCP client unregister, stopping hosted processes, package uninstall, OAuth disconnect and token revocation are distinct actions.
A claude mcp remove command is only valid for Claude Code when the local registration actually has that name. Other MCP hosts require their own UI/config cleanup.
Separate provider credential revocation · publisher documented: Postfleet official docs confirm dashboard-only control plane handles creating AND revoking API keys (pf_*). No key-management operation is provided through MCP/data-plane token, so revoke in account dashboard, then remove client credential separately.
Remove client registration · Claude Code only · MCP100 composed guide
claude mcp remove postfleet

Official Documentation & Sources

What it does

Postfleet gives agents mailboxes and email send/read/reply tools. Inbound messages can be parsed/classified/extracted and screened for prompt injection. Keys are scoped; some sends return pending approval instead of transmitting immediately.

Capability: Communication
Resource type: MCP Server
Best fit: Agent-owned email infrastructure with inbound parsing/injection screening, scoped keys, drafts and human-approval sending.

Representative uses

Create/list mailboxes/domains
Send/reply email
Read/wait for inbound mail
Create/update/send/delete drafts
Use human approval and send allow/block lists

Limitations

Email can contact real people.
Pending-approval response is not a failure and must not be blindly retried.
Inbound webhook delivery is at-least-once and needs event dedupe/signature verification.
Control-plane key creation/revocation is separate from data-plane MCP.

Reviewed access

Access & risk

Review the exact access boundary before connecting this MCP to accounts, credentials, or sensitive data.

Authentication: Scoped bearer key.
Permissions: Mailbox/email/draft authority scoped by key.
Data handling: Email bodies, inbound messages and extracted structured data are processed by Postfleet; webhooks are signed.
Cost: plan_based
Risk and cautions: External communication plus inbound prompt-injection risk; approval and send lists are material controls.

Access scope and cautions

Write actions: Create mailbox/domain state Send/reply email Create/update/send/delete drafts
Sensitive access: Email content Recipient/sender data Extracted message data Bearer key
Risk level: high

FAQ

Based on reviewed evidence as of 2026-10-08. Watchlist tracking is not a recommendation or a security certification.

Which tasks are documented for this implementation?

The reviewed tasks include: Create/list mailboxes/domains; Send/reply email; Read/wait for inbound mail; Create/update/send/delete drafts; Use human approval and send allow/block lists.

What setup and authentication are documented?

Recorded installation/entrypoint step: npx -y @postfleet/mcp. Recorded endpoint: https://api.postfleet.ai/api/mcp. Recorded transport: stdio, streamable_http. Recorded environment-variable notes: POSTFLEET_API_KEY; POSTFLEET_API_URL (optional). No configuration values are supplied here. Prerequisites: Postfleet account/key. These are the documented setup details, not a claim that installation or client compatibility was independently tested. Authentication: Scoped `pf_` bearer key (`bootstrap`, `api`, or `mcp` roles depending task).

Can it modify data or perform write operations?

Documented write actions include: Create mailbox/domain state; Send/reply email; Create/update/send/delete drafts. Recorded permission boundary: Mailbox/email/draft authority scoped by key.

What data-handling boundary should I consider?

Email bodies, inbound messages and extracted structured data are processed by Postfleet; webhooks are signed. Recorded sensitive-access context: Email content; Recipient/sender data; Extracted message data; Bearer key.

What limitations and risks should I check before use?

External communication plus inbound prompt-injection risk; approval and send lists are material controls. Email can contact real people. Pending-approval response is not a failure and must not be blindly retried. Inbound webhook delivery is at-least-once and needs event dedupe/signature verification. Control-plane key creation/revocation is separate from data-plane MCP. Runtime behavior, dependencies and undisclosed vulnerabilities were not independently audited. Documented tool authority and any remote data handling must be checked before installation or use.

What cost model is recorded?

The reviewed cost model is plan based. This classification does not establish current prices, quotas or the cost of every downstream operation. Check the applicable service terms before authorizing paid actions.