io.github.msgwing/zerosmtp
NPM · ZEROSMTP-MCP · SCANNED SEP 20
A free SMTP relay that still takes a username and password, for devices that cannot do OAuth 2.0.
Available components
How this component scores in each security and reliability category. Every signal is checked automatically from public evidence about the published package, including repeated runs of it in an isolated sandbox, and we only credit what we can confirm. How we score → Why this is hard to score →
Supply Chain Security100
- No malware found by supply-chain analysis.Pass
- No known CVEs affecting this package version or its production dependencies.Pass
- No install/post-install scripts declared.Pass
- No production dependencies, so there is no dependency health to assess. View diagnostics → Pass
Provenance & Transparency100
- Source repository is publicly reachable at the declared URL. View diagnostics → Pass
- Cryptographically verified build provenance (signed, bound to msgwing/ZeroSMTP). View diagnostics → Pass
- Clear OSI-approved license (MIT).Pass
- Actively maintained (last published 18 days ago).Pass
- Publishes a security disclosure policy (SECURITY.md).Pass
Schema Quality & AI Usability74
- AI-judged instruction clarity (good).Pass
- Tool/resource definitions use about 362 tokens (~90/item across 4 items; 4 tools + 0 resources), lean.Pass
- Usage-examples check failed: none of the tools include examples. See how to fix → Fail
Stability & Change Management63
- Stability observed for 19 of 30 days with no destabilising changes; credit accrues until the full window elapses.Partial
Tool Coverage100
- 100% of tools have a non-trivial description (not blank, and not just the tool's name).Pass
- 100% of tool parameters carry a description.Pass
Tool Safety100
- No prompt-injection markers were found in the server instructions, tool names or descriptions we captured.Pass
- We read all 4 captured tool definition(s), and no name or description among them implies an irreversible operation.Pass
- An AI judge read all 5 captured unit(s) of tool text and found none that tries to manipulate the model reading it.Pass
Capabilities20
- Spec-recency check failed: implements MCP spec 2024-11-05; the latest is 2026-07-28. See how to fix → Fail
How do I install the io.github.msgwing/zerosmtp MCP server?
io.github.msgwing/zerosmtp runs locally as an npm package, launched with npx -y zerosmtp-mcp. Ready-made configuration for Claude, Cursor, VS Code, Codex and 5 more is on this page, copied from each client's own documentation.
npm · zerosmtp-mcp
claude mcp add msgwing-zerosmtp -- npx -y zerosmtp-mcp
{
"mcpServers": {
"msgwing-zerosmtp": {
"command": "npx",
"args": [
"-y",
"zerosmtp-mcp"
]
}
}
} {
"servers": {
"msgwing-zerosmtp": {
"command": "npx",
"args": [
"-y",
"zerosmtp-mcp"
]
}
}
} codex mcp add msgwing-zerosmtp -- npx -y zerosmtp-mcp
{
"$schema": "https://opencode.ai/config.json",
"mcp": {
"msgwing-zerosmtp": {
"type": "local",
"command": [
"npx",
"-y",
"zerosmtp-mcp"
],
"enabled": true
}
}
} openclaw mcp add msgwing-zerosmtp --command npx --arg -y --arg zerosmtp-mcp
mcp_servers:
msgwing-zerosmtp:
command: "npx"
args: ["-y", "zerosmtp-mcp"] {
"McpServers": {
"msgwing-zerosmtp": {
"Transport": "stdio",
"Command": "npx",
"Arguments": [
"-y",
"zerosmtp-mcp"
]
}
}
} assistant mcp add msgwing-zerosmtp -t stdio -c npx -a -y zerosmtp-mcp
{
"mcpServers": {
"msgwing-zerosmtp": {
"command": "npx",
"args": [
"-y",
"zerosmtp-mcp"
]
}
}
} Every change we have recorded for this component, newest first. Security-relevant changes are always shown. ▲ marks a change for the better, ▼ a change for the worse; unmarked changes are neutral.
- 19 Sept 26 +1
No change was recorded against any check on this day. Stability & Change Management went from 57 to 60. That category is still filling its 30-day observation window: 17 days of observed history at the previous scan, 18 at this one. The score rises as the window fills, whether or not the server changes.
- 17 Sept 26 +1
No change was recorded against any check on this day. Stability & Change Management went from 50 to 53. That category is still filling its 30-day observation window: 15 days of observed history at the previous scan, 16 at this one. The score rises as the window fills, whether or not the server changes.
- 15 Sept 26 +1
No change was recorded against any check on this day. Stability & Change Management went from 43 to 47. That category is still filling its 30-day observation window: 13 days of observed history at the previous scan, 14 at this one. The score rises as the window fills, whether or not the server changes.
- 13 Sept 26 +1
No change was recorded against any check on this day. Stability & Change Management went from 37 to 40. That category is still filling its 30-day observation window: 11 days of observed history at the previous scan, 12 at this one. The score rises as the window fills, whether or not the server changes.
- 11 Sept 26 +1
No change was recorded against any check on this day. Stability & Change Management went from 30 to 33. That category is still filling its 30-day observation window: 9 days of observed history at the previous scan, 10 at this one. The score rises as the window fills, whether or not the server changes.
- 9 Sept 26 +4
- Stability: unverified → 0.27 ▲ functional
- 1 Sept 26 78
First indexed and scored.
Diagnostic detail from the automated scan of this channel: what the scanner observed at each step, so you can see exactly where a check passed or failed. It is informational only and never changes the trust score.
Captured 20 Sept 2026 · Analysed npm/zerosmtp-mcp@1.0.2
Provenance Verified
A signed build attestation was found and verified, binding this exact artifact to the source repository it claims to come from.
| Result | Verified |
|---|---|
| Ecosystem | npm |
| Reason | Verified |
| Discovered via | Registry attestation endpoint |
| Source repo | msgwing/ZeroSMTP |
| Certificate issuer | https://token.actions.githubusercontent.com |
| Certificate SAN | https://github.com/msgwing/ZeroSMTP/.github/workflows/publish-npm.yml@refs/heads/main |
| Rekor log index | 2679216789 |
| Predicate type | https://slsa.dev/provenance/v1 |
| Subject digest | sha512:c5e2ba877b813c757b4520e06bc379bccc1e0ba1c670e662490392302f9aae2694318e27ced7b9f83d0d9dba75c058248cf356d0f69d75869cb2d2b34 |
Background: How many MCP packages publish verified provenance →
Dependencies 0 packages
| Packages resolved | 0 |
|---|---|
| Tree resolution | Complete |
Background: SBOMs and build attestations, explained →
The tools this component advertises to a client, with an estimated token cost for each. Expand a tool to see its parameters and schema. The per-tool counts are indicative and are not scored directly; the schema's total context footprint is one signal in Schema Quality & AI Usability. A tool's description is untrusted text the model reads on every call, which is what makes this list a security surface and not just an inventory: how tool poisoning works →
check_device_oauth ~82
Look up whether a printer, scanner, NAS or firewall has firmware supporting OAuth 2.0 for SMTP, according to the vendor's own published statement. Answers "must this device be replaced or relayed".
| Name | Type | Req | Description |
|---|---|---|---|
| model | string | – | Optional model or series. |
| vendor | string | yes | Vendor, e.g. Canon, Ricoh, Synology. |
No output schema declared.
No examples provided.
check_relay_reachable ~93
Open a real TCP connection and TLS handshake to the relay from THIS machine's network and report what happened. Sends no credentials and no mail. This is the one question documentation cannot answer: whether the firewall in front of the asker permits outbound 587.
| Name | Type | Req | Description |
|---|---|---|---|
| host | string | – | Host, defaults to mx.msgwing.com. |
| port | number | – | Port, 587 (default) or 465. |
No output schema declared.
No examples provided.
lookup_smtp_error ~63
Identify a Microsoft 365 SMTP AUTH error string and say what it means, what caused it, and whether an administrator can still undo the cause. Paste the line the server or the mail library printed.
| Name | Type | Req | Description |
|---|---|---|---|
| text | string | yes | The error string, as printed. |
No output schema declared.
No examples provided.
relay_settings ~36
The ZeroSMTP connection values, together with the two limits that decide whether it is the right answer at all. Returns both without being asked.
Input schema present but exposes no named parameters.
No output schema declared.
No examples provided.
What is the io.github.msgwing/zerosmtp MCP server?
io.github.msgwing/zerosmtp is an MCP server listed in the public MCP registry as io.github.msgwing/zerosmtp. A free SMTP relay that still takes a username and password, for devices that cannot do OAuth 2.0. This page covers its npm package (zerosmtp-mcp).
Is the io.github.msgwing/zerosmtp MCP server safe to use?
io.github.msgwing/zerosmtp scores 87 out of 100 on VerifyMCP. We found no known CVEs affecting it as of 20 September 2026. It declares no install or post-install scripts. Its build provenance is signed and verified. That is a record of what we were able to check automatically, not an endorsement. The category breakdown on this page shows every signal behind the number, including the ones we could not confirm.
What tools does the io.github.msgwing/zerosmtp MCP server expose?
io.github.msgwing/zerosmtp exposes 4 tools: lookup_smtp_error, check_device_oauth, relay_settings, check_relay_reachable. Their descriptions and schemas cost roughly 274 tokens of context every time the server is loaded.
Is the io.github.msgwing/zerosmtp MCP server still maintained?
io.github.msgwing/zerosmtp is still listed as active in the MCP registry. We last reached this channel on 20 September 2026. Those dates come from our own scans of the registry and the channel itself, not from anything the publisher announced.
What licence is the io.github.msgwing/zerosmtp MCP server under?
io.github.msgwing/zerosmtp declares the MIT licence, which is OSI-approved. That covers the source only, and says nothing about the cost of any service it calls.