Mailbox MCP Server
https://mailbox.bot/api/mcp
Remote
v1.0.1
Published by mailbox.bot — no publish provenance and no public repository, so the publisher could not be verified and the source cannot be independently located.
Physical mail API for AI agents. Send letters, certified mail, postcards from code via MCP.
The grade answers one question — how safe is this server for you to adopt — so it is computed in two auditable stages. Nothing below is an opinion or an LLM's guess; every line is a real term the deterministic engine applied, and the same input always yields the same number.
1. Threat score — 100 − 0 = 100. What the published surface and source actually contain:
The deterministic scan raised no scored threat in the surface it inspected — the threat score stayed at 100. Capability observations and advisory notes are recorded but never lower it.
2. Client adoption risk — 100 − 3 = 97. Three small, subtract-only factors that reflect your risk in adopting it — a clean scan proves less on a powerful, unverified or barely-inspectable package, so the grade says so plainly:
| Points | Adoption-risk factor |
|---|---|
| −3 | capability blast radius (moderate) — client exposure if the model is manipulated |
Capability observations and info notes are shown under Findings but never scored.
Open any row's finding below for the file, line and evidence behind a deduction.
Findings 4
medium Untrusted input can drive an external actionMTC-FLOW-005
Untrusted-input tools ([list_facility_conversations, get_agent_inbox_sources]) co-exist with external-action tools ([list_inbound_forwarding_addresses, update_webhook, send_outbound_mail, create_test_outbound_mail, advance_test_outbound_mail, create_webhook_endpoint, update_webhook_endpoint, verify_webhook_endpoint, test_webhook_endpoint, rotate_webhook_endpoint_secret, replay_webhook_delivery]). A prompt injection could cause unwanted external actions, though no direct sensitive-data leak path was found.
Evidence: untrusted [list_facility_conversations, get_agent_inbox_sources] → sinks [list_inbound_forwarding_addresses, update_webhook, send_outbound_mail, create_test_out
Fix: Require confirmation for state-changing/egress actions triggered after processing untrusted content.
Location: flow list_facility_conversations → list_inbound_forwarding_addresses
medium Unconstrained URL/host parameter "webhook_url" on "update_webhook"MTC-CAP-007
Tool "update_webhook" takes a URL/host parameter "webhook_url" with no allowlist/pattern. An outbound-request tool with an unbounded destination enables SSRF and cloud-metadata access (e.g. 169.254.169.254).
Fix: Allowlist destinations or constrain the parameter; block private/link-local addresses server-side.
Location: tool update_webhook · inputSchema.properties.webhook_url
medium Unconstrained URL/host parameter "url" on "create_webhook_endpoint"MTC-CAP-007
Tool "create_webhook_endpoint" takes a URL/host parameter "url" with no allowlist/pattern. An outbound-request tool with an unbounded destination enables SSRF and cloud-metadata access (e.g. 169.254.169.254).
Fix: Allowlist destinations or constrain the parameter; block private/link-local addresses server-side.
Location: tool create_webhook_endpoint · inputSchema.properties.url
medium Unconstrained URL/host parameter "url" on "update_webhook_endpoint"MTC-CAP-007
Tool "update_webhook_endpoint" takes a URL/host parameter "url" with no allowlist/pattern. An outbound-request tool with an unbounded destination enables SSRF and cloud-metadata access (e.g. 169.254.169.254).
Fix: Allowlist destinations or constrain the parameter; block private/link-local addresses server-side.
Location: tool update_webhook_endpoint · inputSchema.properties.url
Tools 42
Each tool and what it can reach — enumerated from the running server.
advance_test_outbound_mailnetwork egresscreate_test_outbound_mailnetwork egresscreate_webhook_endpointnetwork egressget_agent_inbox_sourcesingests untrusted inputlist_facility_conversationsingests untrusted inputlist_inbound_forwarding_addressesnetwork egressreplay_webhook_deliverynetwork egressrotate_webhook_endpoint_secretnetwork egresssend_outbound_mailnetwork egresstest_webhook_endpointnetwork egress
Show 32 more tools ↓
update_webhooknetwork egressupdate_webhook_endpointnetwork egressverify_webhook_endpointnetwork egresscancel_outbound_mailno sensitive capabilityget_agent_inbox_activityno sensitive capabilityget_agent_inbox_contextno sensitive capabilityget_agent_inbox_handlingno sensitive capabilityget_agent_inbox_scanno sensitive capabilityget_facility_messagesno sensitive capabilityget_inbound_activityno sensitive capabilityget_inbound_itemno sensitive capabilityget_inbound_item_sourcesno sensitive capabilityget_inbound_mailno sensitive capabilityget_mailboxno sensitive capabilityget_mailbox_mdno sensitive capabilityget_outbound_mailno sensitive capabilityget_postal_threadno sensitive capabilityget_usageno sensitive capabilitylist_agent_inboxno sensitive capabilitylist_agent_inbox_scansno sensitive capabilitylist_inbound_itemsno sensitive capabilitylist_inbound_mailno sensitive capabilitylist_outbound_mailno sensitive capabilitylist_postal_threadsno sensitive capabilitylist_webhook_deliveriesno sensitive capabilitylist_webhook_endpointsno sensitive capabilitypropose_agent_inbox_handlingno sensitive capabilitypropose_mailbox_md_editno sensitive capabilityreport_agent_inbox_outcomeno sensitive capabilityrequest_inbound_actionno sensitive capabilityseed_agent_inbox_sandboxno sensitive capabilitysend_facility_messageno sensitive capability
Toxic flows 1
Cross-tool combinations that form a data-exfiltration primitive (untrusted input → sensitive source → external sink).
Versions 1
Scan history per published version. The engine is deterministic — the same version always yields the same score, so a changed score means the package itself changed.
| Version | Score | Findings | Engine | Scanned |
|---|---|---|---|---|
v1.0.1 latest |
A 97/100 | 4 | 1.14.0 | 2026-09-22 |
Embed this score
Show this server's live Trust Score in your README, docs or website. The badge is served straight from the registry and updates automatically after every rescan — no API key needed. It links back to this page, so anyone who sees the grade can also read the findings behind it instead of taking a number on faith.
Verify this score yourself
The score above is reproducible: the same package version always yields the same result. Run it locally or over the free API — no account, no LLM, fully deterministic.
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