Healthchecks README
The full upstream README, mirrored here for reference. Install config, tool schemas, adoption signals, and an original overview live on the Healthchecks listing page.
healthchecks-mcp
A Model Context Protocol (MCP) server for Healthchecks, the dead man's switch for cron jobs and scheduled tasks — it alerts you when a job stops checking in. Works against the hosted service and against a self-hosted instance alike.
Lets MCP clients like Claude Code, Claude Desktop or Codex see which scheduled jobs are healthy, read the output the failing one reported, and create or adjust checks — with the irreversible operations behind a confirmation token and the write tools switchable off entirely.
Fourteen tools is the ceiling, not the floor:
HEALTHCHECKS_ALLOW_TOOLS=essential registers a curated seven instead, and a
model picks the right tool far more reliably from seven than from fourteen — see
choosing which tools load.
What makes it different
It reads the ping bodies. get_ping_body returns what a job actually printed
when it reported failure. Every other question — which check is down, since when,
how often — is one step away from that one, and it is the endpoint the other
Healthchecks MCP servers leave out.
Read-only API keys work properly. Healthchecks hands a read-only key a
different object: no uuid, no ping_url, no channels — a 40-character
unique_key instead. This server addresses checks by either, and
get_api_key_info tells you up front which kind of key you configured and which
tools it cannot reach, rather than leaving you with a 401 missing api key for a
key that was sent.
It never pings a check. Pinging is how a job reports that it ran. A tool that could ping would let a model make a dead job look alive, which is the one thing monitoring must not allow — see Not exposed, on purpose.
It knows where this API is sharp. timeout and schedule cannot be combined
because the upstream silently discards one of them; tags are validated against
their space separator and keywords against their comma; a new check is given
every integration unless you say otherwise, because the API's own default is a
check that alerts nobody.
Requirements
- Node.js ≥ 22
- A Healthchecks project API key — Project Settings → API Access. Keys are per project, not per account, and are exactly 32 characters long.
Configuration
| Variable | Required | Description |
|---|---|---|
HEALTHCHECKS_API_KEY | yes | Project API key. A read-only key works for part of the tool surface — see below |
HEALTHCHECKS_URL | no | Site root of a self-hosted instance, e.g. https://hc.example.net. Default https://healthchecks.io |
HEALTHCHECKS_READ_ONLY | no | true registers only the read tools |
HEALTHCHECKS_ALLOW_TOOLS | no | Comma-separated tool names, list_* prefixes, or essential for a curated preset |
HEALTHCHECKS_DENY_TOOLS | no | Same syntax; removed from whatever HEALTHCHECKS_ALLOW_TOOLS left |
HEALTHCHECKS_INSECURE_TLS | no | true accepts self-signed certificates (scoped to this connection) |
ELICITATION | no | false replaces the approval dialog with the two-call token. Not prefixed |
HEALTHCHECKS_URL is the site root, not the API root: https://hc.example.net,
not https://hc.example.net/api/v3. Both are accepted — the suffix is trimmed —
because the API documentation spells every example the long way.
Use
https://. Over plain http the API key travels unencrypted; the server prints a warning unless the host is local. For self-signed certificates prefer a proper internal CA overHEALTHCHECKS_INSECURE_TLS.
Without an API key the server still starts and lists its tools (so registries and
inspectors can introspect it), but every call except get_status fails with setup
instructions instead of reaching the API.
Read-only keys. Healthchecks gates three tools that only read — list_pings,
get_ping_body and list_integrations — behind a read-write key anyway. With a
read-only key those fail, along with all five write tools.
The failure does not look like a permission problem: the API answers
401 {"error": "wrong api key"}, which reads as if the key were wrong or
missing. It is not — those three tools translate it into what actually happened.
get_api_key_info reports which kind of key is configured, and
HEALTHCHECKS_DENY_TOOLS is the tidy way to stop offering them at all.
Choosing which tools load
HEALTHCHECKS_ALLOW_TOOLS and HEALTHCHECKS_DENY_TOOLS take comma-separated tool
names; a trailing * matches a whole family. essential is a curated preset —
list_checks, get_check, list_pings, list_flips, create_check,
update_check and resume_check — marked as such in the
tool reference.
An entry that matches no tool aborts startup and names it, so a typo cannot silently
hide a tool — an absent tool is not something anyone traces back to an environment
variable. A filtered tool is never registered, so it is absent from tools/list and
unknown to tools/call alike, exactly like a write tool under
HEALTHCHECKS_READ_ONLY.
If you run several of these servers at once, mcp-hub is
the other answer — its /hub endpoint replaces every server's tools with six
meta-tools.
Installation
Claude Code
Claude Desktop
Codex
Docker
Add -e HEALTHCHECKS_URL=https://hc.example.net for a self-hosted instance.
Through mcp-hub
A client that cannot spawn a local process — ChatGPT connectors, Claude on the web,
Cursor, LibreChat — reaches healthchecks-mcp through mcp-hub: one
container serves many stdio MCP servers over Streamable HTTP, with an OAuth 2.1 login
behind a single password and long-lived tokens for the clients that cannot do OAuth. Its
/hub endpoint puts every server behind six meta-tools, so one connector reaches all of
them without N×tool schemas in the model's context, and it speaks both protocol revisions
— a question this server asks travels through it to the person at the far end.
Its /config/mcp.json uses Claude Code's format, so the entry is the one you already
have:
allowTools and denyTools there are the hub's own per-server filter, which is not
the same thing as *_ALLOW_TOOLS in env — the difference, and the mistake it invites,
are in the client guide.
Tools
Read tools are always registered. 🔑 marks the ones Healthchecks requires a read-write key for even though they only read; 👤 marks the ones that ask for a confirmation token before acting.
| Tool | Description |
|---|---|
list_checks | Checks in the project, with tag, slug and status filters |
get_check | One check with every field, by UUID or unique_key |
list_pings 🔑 | Recent pings of a check, newest first |
get_ping_body 🔑 | The body a job POSTed with one ping — its output |
list_flips | Up/down transitions of a check, with a time window |
list_integrations 🔑 | Notification integrations and the UUIDs the write tools accept |
list_badges | Status badge URLs, per tag and for the project |
get_status | Whether the instance is reachable — needs no API key at all |
get_api_key_info | Which instance, which kind of key, and what that key cannot do |
Write tools are registered unless HEALTHCHECKS_READ_ONLY=true.
| Tool | Description |
|---|---|
create_check | Creates a check. Notifies every integration unless channels says otherwise |
update_check | Changes the given fields. channels replaces the list rather than adding to it; an empty list is refused |
pause_check | Stops the check expecting pings — and alerting. resume_check puts it back |
resume_check | Puts a paused check back into the new state |
delete_check 👤 | Deletes a check. The UUID is not recoverable |
Structured output
Every tool declares an outputSchema and answers with structuredContent
alongside the text block, so a client can use the result without parsing prose:
Every tool that reports anything from the instance carries untrusted: true
and source: "healthchecks" as fields — a check name, a description and above
all a logged ping body are written by whoever pinged, and a ping URL sits in a
cron job on every monitored host. get_api_key_info is without it, and
get_status carries it only when the instance answered something other than
OK: a plain OK is this server's own sentence, and a marker on everything is
a marker that means nothing.
Fields this server builds are described exactly; a check record is left open,
because normalizeCheck passes through whatever a self-hosted release chose to
add and the SDK validates every result against its schema before it goes out.
Not exposed, on purpose
- Pinging. The server never calls a ping URL. Pinging is how a job says it ran; a tool that could ping would let a model — or text a model read — report success for a job that never executed, and a monitoring system that can be talked into a green status is worse than none.
- Ping keys. They are not readable through the Management API, and this server does not ask for one.
- Creating integrations. The API has no endpoint for it; they are configured
in the web UI.
list_integrationsreads them. - The
uniqueupsert as a default.create_checkaccepts it and says loudly in its result when it was used, because it turns a create into a silent update of a check that already exists.
Safety
delete_checkasks a person. Where the client supports MCP elicitation it raises a real dialog that the model cannot answer on its behalf; where it does not, it falls back to a short-lived token bound to that exact check and that exact operation, and says so rather than implying somebody approved.pause_checkis deliberately not asked about —resume_checkputs it back and nothing is lost in between, and a dialog in front of a reversible change is how people learn to tick without reading. See Asking a person.- Confirmation prompts never quote content from Healthchecks — a check's name and description are free text this server does not control, and that text is read by a model.
- Ping bodies and check descriptions are marked as untrusted data, because anything that can ping a check can write into them.
- Error bodies are truncated, HTML error pages are dropped, and every response has a byte ceiling enforced while it streams — the Management API paginates nothing.
HEALTHCHECKS_READ_ONLY=truedoes not register the write tools at all, andHEALTHCHECKS_DENY_TOOLScuts finer along the same line — a filtered tool is never built, not refused at call time.- The API key is deleted from
process.envonce it has been read, and never travels in a request body.
Documentation
The full guide, tool reference and security notes live at
healthchecks-mcp.ni-c.de (source in docs/).
Development
Releasing
- Add the CHANGELOG entry and bump
package.json. npm run lint && npm run build && npm run test:coverage- Commit, then push a signed tag:
git tag -s vX.Y.Z -m "vX.Y.Z" && git push origin main vX.Y.Z
The release workflow publishes to npm (Trusted Publishing, with provenance), creates the GitHub release from the CHANGELOG section and updates the MCP Registry entry.
Contributing
Issues, discussions and pull requests are welcome — see CONTRIBUTING.md. For vulnerabilities please use private reporting rather than a public issue; the policy is in SECURITY.md.
License
MIT © Willi Thiel