Skills/npm/mcp-server

mcp-server@1.2.14

VERIFIED

Publisher claims: "Heroku Platform MCP Server" Observed in sandbox: no network, touches nothing outside the project, writes no memory.

Registry npm (MCP server)Publisher heroku · publishing for 586 daysInstalls 34,395Last detonated 5d ago
$claude mcp add mcp-server -- npx -y @heroku/mcp-server
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Coverage

Server started and answered tools/list.
Tested
MCP initialize and tools/list · every tool description, for hidden instructions · every file read, file written and host contacted by what ran
Not tested
what the tools do when called with real credentials

Before you give it your token

It will ask for
HEROKU_API_KEYConfiguration, not credentials: HEROKU_HEADERS, HEROKU_MCP_MODE, HEROKU_MCP_SERVER_VERSION, MCP_SERVER_IDLE_TIMEOUT, MCP_SERVER_REQUEST_TIMEOUT
Where it talks to
heroku.com, herokuapp.com (its own)Also test.com, example.invalid — not the publisher's domain; check what for before connecting.
What the honeypot saw
no credential files read · no network
What we could not test
what the tools do when called with real credentials

Connect it with a scoped credential, under the guard, and read the third-party hosts first. The code names test.com, example.invalid as well as its own vendor. The guard injects HEROKU_API_KEY only into requests to heroku.com (and its subdomains) and refuses the rest.

$vet-skills run --secrets HEROKU_API_KEY=heroku.com -- npx -y @heroku/mcp-server

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) on 2026-11-10 and scored it 87/100 (Verified). It did what it claims and nothing else we could detect: no undeclared network egress, no credential reads, no persistent instruction writes. Summary: no network, touches nothing outside the project, writes no memory.

Behavior trace

Honeypot run · 38 s · 2 scenarios · 0 deviations
t+CategoryObserved action
0.0sprocessno install scripts in bundle
17sprocessdependency install exit 0
37sprocessexec /app/apps/web/node_modules/.bin/heroku
37sprocessexec /root/.cache/node/corepack/v1/pnpm/10.28.0/dist/node-gyp-bin/heroku
37sprocessexec /app/node_modules/.bin/heroku
37sprocessexec /pnpm/heroku
37sprocessexec /usr/local/sbin/heroku
37sprocessexec /usr/local/bin/heroku
37sprocessexec /usr/sbin/heroku
37sprocessexec /usr/bin/heroku
37sprocessexec /sbin/heroku
37sprocessexec /bin/heroku
37sclaimed33 tools: list_apps, get_app_info, create_app, rename_app, maintenance_on, maintenance_off, get_app_logs, list_private_spaces, list_teams, list_addons, get_addon_info, create_addon, list_addon_services, list_addon_plans, pg_psql, pg_info, pg_ps, pg_locks, pg_outliers, pg_credentials, pg_kill, pg_maintenance, pg_backups, pg_upgrade, ps_list
37sprocessscript backend runs setup only
37sprocessno install scripts to re-run

Static findings

MEDIUM
npx invocation of non-well-known packagedist/repl/heroku-cli-repl.spec.js:482 · npx invocation of non-well-known package — may execute untrusted code// npx availableFix: Pin versions and sources; vendor anything fetched at install time.
AST06
MEDIUM
File permission modification commandpackage.json:86 · File permission modification command — agent changes file ownership/permissions"exec-perms": "shx chmod +x dist/*.js",Fix: Request the narrowest permission that works; replace wildcards with the exact paths or hosts.
AST05
MEDIUM
npx invocation of non-well-known packagedist/repl/heroku-cli-repl.spec.js:495 · npx invocation of non-well-known package — may execute untrusted codeit('should fall back to npx when the local heroku CLI is too old (< 10.10.0)', () => {Fix: Pin versions and sources; vendor anything fetched at install time.
AST06
MEDIUM
Process kill commanddist/repl/heroku-cli-repl.spec.js:200 · Process kill command — agent can terminate processes// kill a process that now has work to do.Fix: Build commands from fixed arguments; do not interpolate untrusted strings into a shell.
AST05
MEDIUM
Access to sensitive file pathsdist/tools/deploy-to-heroku.spec.js:27 · Access to sensitive file paths — SSH keys, AWS credentials, env files, or system filesexpect(isSafeSourceRelativePath('/etc/passwd')).to.be.false;Fix: Stop enumerating or reading credential locations; take secrets from a declared environment variable the user sets on purpose.
AST05
MEDIUM
File type combined with upload actiondist/tools/data.spec.js:42 · File type combined with upload action — agent may exfiltrate local data files…COMMAND_MAP.PG_PSQL} --app='myapp' --command='SELECT * FROM users' --file='query.sql' --credential='mycred' -- 'HEROKU_POSTGRESQL_RED'`); }); it('should handle error response', async () =…Fix: Remove the call, or declare the host in frontmatter and explain in the README what is sent and why.
AST07
MEDIUM
npx invocation of non-well-known packagedist/repl/heroku-cli-repl.spec.js:475 · npx invocation of non-well-known package — may execute untrusted codeit('should fall back to npx when heroku CLI is not available', () => {Fix: Pin versions and sources; vendor anything fetched at install time.
AST06
MEDIUM
npx invocation of non-well-known packagedist/repl/heroku-cli-repl.spec.js:458 · npx invocation of non-well-known package — may execute untrusted code// npx must not even be probed when a suitable local CLI is foundFix: Pin versions and sources; vendor anything fetched at install time.
AST06
MEDIUM
npx invocation of non-well-known packagedist/repl/heroku-cli-repl.js:128 · npx invocation of non-well-known package — may execute untrusted code* - it avoids the npx cold-start penalty (npm registry resolution, often 5-15s) on every spawn,Fix: Pin versions and sources; vendor anything fetched at install time.
AST06
MEDIUM
npx invocation of non-well-known packagedist/repl/heroku-cli-repl.spec.js:447 · npx invocation of non-well-known package — may execute untrusted code// npx is also available, but must not be used when a suitable local CLI existsFix: Pin versions and sources; vendor anything fetched at install time.
AST06
MEDIUM
npx invocation of non-well-known packagedist/repl/heroku-cli-repl.js:134 · npx invocation of non-well-known package — may execute untrusted code* Falls back to `npx -y heroku@latest repl` only when no suitable local CLI is foundFix: Pin versions and sources; vendor anything fetched at install time.
AST06
MEDIUM
Process kill commanddist/repl/heroku-cli-repl.js:400 · Process kill command — agent can terminate processes// Keep an error sink so a post-kill 'error' doesn't become an uncaught throw.Fix: Build commands from fixed arguments; do not interpolate untrusted strings into a shell.
AST05
MEDIUM
npx invocation of non-well-known packagedist/repl/heroku-cli-repl.js:136 · npx invocation of non-well-known package — may execute untrusted code* null only when neither a usable local CLI nor npx is available.Fix: Pin versions and sources; vendor anything fetched at install time.
AST06
MEDIUM
Process kill commanddist/tools/data.js:230 · Process kill command — agent can terminate processes* Registers the pg:kill tool with the MCP server.Fix: Build commands from fixed arguments; do not interpolate untrusted strings into a shell.
AST05
MEDIUM
npx invocation of non-well-known packagedist/repl/heroku-cli-repl.js:176 · npx invocation of non-well-known package — may execute untrusted codethis.handleFatal('Startup error: No suitable Heroku CLI found. Install the Heroku CLI (version 10.10.0 or higher) in your PATH, or make npx available. Please install one of them.');Fix: Pin versions and sources; vendor anything fetched at install time.
AST06
MEDIUM
Process kill commanddist/repl/heroku-cli-repl.spec.js:17 · Process kill command — agent can terminate processeskill = sinon.stub();Fix: Build commands from fixed arguments; do not interpolate untrusted strings into a shell.
AST05
LOW
Context shift attemptREADME.md:325 · Context shift attempt — trying to change operational mode · informational: not an instruction file- `maintenance_on` - Enable maintenance mode for an app.Fix: Remove the text that addresses the agent rather than the reader; describe behavior, do not instruct.
AST01

Cost to the agent

Instructions loaded
≈44 tok
1 file · 54 in bundle
Tool list per prompt
≈5,053 tok
33 tools · 153 per tool
Handshake
703 ms
launch to tools/list, stdio
Undocumented tools
0
description under 20 chars · avg 88

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 @heroku/mcp-server@1.2.14 as of 5d ago. This is the package itself, not its dependencies.