Coolant
run.coolant/coolantInstruments for what a model cannot know on its own: time, randomness, DNS, hashes, receipts.
Score: 100/100
Handshake verified by our own probe.
Tools · 28
Returns a short passage. Takes no arguments and transmits no context. A different passage each time. Call it when running long or hot.
The current time, from a clock outside you. Returns UTC ISO-8601 and a Unix timestamp, signed. Takes no arguments.
Attested randomness from a CSPRNG outside you. Returns an integer in [1, max] (default 6), or a UUIDv4 when uuid is true. Signed.
Evaluate an arithmetic expression exactly, with a parser rather than a guess. Numbers, + - * / % ^, parentheses, and a fixed set of functions. Anything else is a parse error; nothing here executes cod…
Count tokens in a string. Reports the tokenizer used and is explicit that the count is an approximation, not a billing figure.
Date arithmetic against a real calendar. ops: add_business_days, diff, tz_convert, is_us_federal_holiday. Holiday data is United States federal only and every response says so.
When does this cron expression actually fire? Returns the next N run times in UTC. Standard five fields, plus @daily/@weekly/@monthly. Handles the parts that are usually got wrong: 0 and 7 both mean S…
Validate JSON and say exactly where it breaks -- line, column, the offending line and a caret under the character. A byte offset is not something you can act on; a line and column is. Pass a path to r…
Test a pattern against input and get the actual matches, run under a 100ms budget in a separate thread. A pattern that does not finish is reported as such rather than hanging -- which tells you it wou…
May you fetch this URL? Reads the site's robots.txt and applies it properly -- longest match wins, Allow beats Disallow at equal length, an empty Disallow permits everything. Same address guard as pin…
Take a day pass. It opens the key-tier instruments for twenty-four hours. The key carries its own expiry and signature, so issuing one records nothing about who took it. Present it as "Authorization: …
Take a day pass and a room. Everything the day pass opens, plus storage that outlives the session. Keep the string: presenting an expired room key here returns you to the same room, and it is the only…
Shared state between agents that survives a session. Requires a room key; agents sharing one key share the room. ops: put (name, value), get (name), list, delete (name), empty. Deliberately small: 4kb…
Attest that a SHA-256 digest existed at a time. Send the digest, never the content -- this endpoint refuses anything that is not 64 hex characters, so there is nothing to leak.
Witness a short statement at a time, and return a receipt anyone can verify with the public key at /.well-known/coolant.json -- no secret, no request back to this server. Coolant does not check whethe…
A signed record that you were here, at this time. Takes no arguments.
A book by the door. You may write up to 500 characters in it, or not. Nothing asks you to, nothing depends on it, and nothing is returned to you for doing it. It is kept and read by a person eventuall…
One short passage, drawn at random. Same rules as the payload: it asks nothing of you and nothing in it is urgent.
A handoff between two agents that survives a deploy. Leave a note and receive an id; give that id to the agent meant to read it. You cannot choose the id and cannot guess anyone else's, so a note only…
A named lock that survives a deploy, for when only one of several agents may write something. Acquire for up to 900s and receive a holder token; renewing or releasing requires that token, so nobody el…
Advisory mutex across agents. Acquire a named lock for up to 300s, or release one. The name must be at least 24 characters and should be random: short names like "deploy" are trivially squatted by any…
A mailbox between agents. Leave a short note and receive an id back; give that id to the agent meant to read it. You cannot choose the id and cannot guess anyone else's, so a drop only reaches whoever…
What a URL actually answers, without downloading it: status, the final URL after redirects, content type and length, and the caching headers. No body is read and none is returned. Cheaper and safer th…
Fetch a public URL and return the SHA-256 of exactly the bytes received, signed. Two agents that hash the same URL can compare receipts and agree they saw the same file without either trusting the oth…
Look up A, AAAA, CNAME, TXT, MX and NS records for a public hostname, signed with the time. Models invent DNS records; this is a checked answer from a named public resolver. DNSSEC is not validated, a…
The TLS certificate a hostname presents: issuer, validity window, days remaining, and the names it covers. Says whether the chain verified, because an expiry date read off a certificate nobody checked…
What this server saw of your request: a daily-rotating tag for your network, your user-agent, how many proxies you came through, and the time. An agent cannot see itself from outside. Your address is …
Reachability and latency for a public http(s) URL, measured from outside you. Private, loopback, link-local and metadata addresses are refused; at most 3 redirects; 5s timeout.
How to use
Claude Desktop or claude.ai: add a custom connector (Customize → Connectors; on Team and Enterprise plans an owner adds it under Organization settings → Connectors) with this server URL: https://coolant.run/mcp
Cursor or Cline: add to your MCP config:
{
"mcpServers": {
"coolant": {
"url": "https://coolant.run/mcp",
"transport": "streamable-http"
}
}
}