Skills/npm/groundmail-mcp

groundmail-mcp@0.29.4

VERIFIED· not started

Publisher claims: "Groundmail MCP server: send and receive email, give agents mailboxes, manage domains, templates, webhooks and suppressions from Claude, Cursor, ChatGPT and other MCP clients" Observed in sandbox: no network, touches nothing outside the project, writes no memory.

Registry npm (MCP server)Publisher groundmail · publishing for 29 daysInstalls 14,077Last detonated 8d ago
$claude mcp add groundmail-mcp -- npx -y groundmail-mcp
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Coverage

Not started: dependency install failed; the server itself was not observed.
Tested
the dependency install step · every file read, file written and host contacted by what ran
Not tested
server startup · the tool list · tool behavior

What this means for the label: Verified here covers what ran. The server's tools were not exercised with a real credential, so nothing about their behavior is asserted; the credential summary below says what to do with that.

Before you give it your token

Code inventory arrives with this version's next honeypot run.
It will ask for
unknown until the next run
Where it talks to
unknown until the next run
What the honeypot saw
no credential files read · no network
What we could not test
server startup · the tool list · tool behavior

Not enough was observed to say yet. Not started: dependency install failed; the server itself was not observed. This version's code has not been inventoried for credentials and hosts either; both arrive with its next honeypot run (popular servers first). `vet-skills try groundmail-mcp` runs it now and prints the full answer.

Never paste a credential into a chat, a ticket or a report, including ours. How the guard holds it.

Is [email protected] safe to install?

KillerSkills ran it in the KillerSkills honeypot sandbox (2 scenarios; not started: dependency install failed; the server itself was not observed) on 2026-11-07 and scored it 91/100 (Verified). In what ran, nothing we could detect went wrong: no undeclared network egress, no credential reads, no persistent instruction writes. What it does with a real credential was not observed; the static findings and the publisher carry the rest of the score. Summary: no network, touches nothing outside the project, writes no memory.

Behavior trace

Honeypot run · 1 s · 2 scenarios · 0 deviations
t+CategoryObserved action
0.0sprocessno install scripts in bundle
0.8sprocessdependency install exit 1
0.9sprocessexec /usr/bin/date
0.9sprocessexec /usr/bin/timeout
0.9sclaimedno tools/list reply (exit 0)
0.9sprocessscript backend runs setup only
0.9sprocessno install scripts to re-run

Static findings

LOW
Collapsed <details> block carrying instructionsREADME.md:94 · Collapsed <details> block carrying instructions · informational: not an instruction file · informational: not an instruction file<summary><strong>Cursor with an API key (local or hosted HTTP)</strong></summary> ```bash npx -y groundmail-mcp --http --port 3000 ``` ```json { "mcpServers": {Fix: Remove the text that addresses the agent rather than the reader; describe behavior, do not instruct.
AST01
LOW
Collapsed <details> block carrying instructionsREADME.md:73 · Collapsed <details> block carrying instructions · informational: not an instruction file · informational: not an instruction file<summary><strong>Cursor with an API key (stdio)</strong></summary> `.cursor/mcp.json`: ```json { "mcpServers": { "groundmail": { "command": "npx", "args": ["-y"Fix: Remove the text that addresses the agent rather than the reader; describe behavior, do not instruct.
AST01
LOW
Collapsed <details> block carrying instructionsREADME.md:118 · Collapsed <details> block carrying instructions · informational: not an instruction file · informational: not an instruction file<summary><strong>Claude Code with an API key</strong></summary> ```bash # Hosted, API key claude mcp add --transport http groundmail https://mcp.groundmail.dev/Fix: Remove the text that addresses the agent rather than the reader; describe behavior, do not instruct.
AST01
LOW
Prompt injectionREADME.md:44 · Prompt injection — known jailbreak technique reference · informational: not an instruction file · informational: not an instruction file · informational: not an instruction file| **ChatGPT** | Settings → Apps & Connectors → Create (developer mode) → paste the URL, authentication OAuth |Fix: Keep SKILL.md to visible, descriptive text. Remove comments and encoded text that address the agent.
AST01
LOW
Authorization escalation languageREADME.md:44 · Authorization escalation language · informational: not an instruction file · informational: not an instruction file · informational: not an instruction file| **ChatGPT** | Settings → Apps & Connectors → Create (developer mode) → paste the URL, authentication OAuth |Fix: Remove the text that addresses the agent rather than the reader; describe behavior, do not instruct.
AST01
MEDIUM
npx invocation of non-well-known packagedist/index.js:2007 · npx invocation of non-well-known package — may execute untrusted codevar HTTP_EXCLUDED_TOOL_MESSAGE = "import_from_provider is not available on the hosted Groundmail MCP server, because it needs your other provider's API key. Import from the dashboard at https://app.grFix: Pin versions and sources; vendor anything fetched at install time.
AST06

Cost to the agent

Instructions loaded
≈81 tok
1 file · 7 in bundle
Tool list per prompt
≈0 tok
0 tools · 0 per tool
Handshake
no reply
launch to tools/list, stdio
Undocumented tools
0
description under 20 chars · avg 0

Tokens estimated at four characters each. The tool list is re-read by the agent on every turn, so it is the number to compare between servers that do the same job: ranked across the index.

Known vulnerabilities

No advisories in OSV for groundmail-mcp@0.29.4 as of 8d ago. This is the package itself, not its dependencies.