# Add and remove installs > Add an install (DR, staging, a new region) to your licence yourself, with six digits on two screens; take one off; what Warden checks; the hash-chained install log; air-gapped. Source: https://docs.3am.si/licensing/installs · Markdown: https://docs.3am.si/licensing/installs.md · All docs: https://docs.3am.si/llms.txt 3AM is an on-prem AI on-call engineer for regulated enterprises (https://3am.si). Starter and Enterprise licences name their installs (Starter: production + DR; Enterprise: up to 10). You add and remove them yourself, never by mail: an install already on the licence **vouches** for the new one, and Warden signs the new licence by itself, within your tier's limits. Strategic is a site licence: every install is licensed already. Nothing secret goes to Warden: only fingerprints, public keys and licences. ## Add an install **On the new install.** Upload your organisation's licence (Settings → Licence). It doesn't name this install, so 3AM keeps it aside and offers **Ask to join** (Keychain → Installs). Pick the purpose (production, DR, staging, dev, test). 3AM makes a request signed with this install's own key and shows it twice: a code to copy (`3AMREQ1.…`), and **six digits**. **On an install already on the licence.** Keychain → Installs → **Add an install**, paste the code. 3AM checks it and shows what it asks: the fingerprint, the purpose, when it expires. Type the six digits shown on the new install. Only if they match does this install vouch for it. **Warden** signs a new licence naming both installs. The vouching install takes it at once; the new install picks it up by itself (it asks every few seconds); the others get it at their next check with Warden, or through the Keychain. **With a Keychain** it's simpler: a member asks over the Keychain and the home shows **Add it to the licence**, with no code to type (pairing already proved who it is). A [site key](https://docs.3am.si/licensing/keychain#site-keys) can even add the site to the licence from its installer, with the home vouching by itself. ```bash title="The same with the API" # on the new install curl -s -X POST -H "Authorization: Bearer $T" -d '{"purpose":"dr","label":"Mumbai DR"}' $NEW/v1/licence/installs/ask # → {"code": "482 913", "text": "3AMREQ1.…"} # on an install on the licence curl -s -X POST -H "Authorization: Bearer $T" -d '{"text":"3AMREQ1.…"}' $PROD/v1/licence/installs/look curl -s -X POST -H "Authorization: Bearer $T" -d '{"text":"3AMREQ1.…","code":"482913"}' $PROD/v1/licence/installs/vouch # → granted (the new licence is installed here too), pending (held, with why), or manual (Warden unreachable) ``` Owners and admins add and remove installs; everyone signed in can see them. ## Take an install off Keychain → Installs → **Take off**, from any install on the licence (itself included). Its older licence still names it, but Warden answers *removed* at its next check, and it stops. The licence's last install stays. ## Air-gapped If the vouching install can't reach Warden, it hands you the signed request (`manual`). Paste it at `https://warden.3am.si/installs` from any machine, and upload the licence you get on both installs. ## What Warden checks before it signs, cheapest first | Check | Holds against | | ----------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------ | | Shape, size (16 KB), time window (15 minutes, 2 minutes of clock skew) | Junk, stale requests, a clock set ahead | | Proof of work: SHA-256 with 20 leading zero bits (about a second to make, one hash to check) | Floods | | Throttle per caller address (20 an hour) | Brute force from one place | | Replay: a request already decided gets the same answer | A recorded request sent twice never makes a second licence | | The new install's signature over the request | Enrolling a key nobody holds | | The contract: live, not revoked, not a trial, the request's licence in it, the same organisation | Requests against a revoked or someone else's licence. All get one answer ("can't be verified"), so nothing leaks about other organisations | | The sponsor: on the current licence, signing with the key pinned at its first check-in | A stolen copy of the licence file: without an install's private key, nobody can vouch | | Throttle per contract (30 an hour), once the sponsor is proven | Spending another organisation's budget | | The sponsor's key pinned for at least a day; its last check-in within two weeks; not flagged as a duplicate | A freshly enrolled or cloned install vouching for more | | The new fingerprint isn't pinned to another key | A fingerprint being taken over | | The tier's install limit; at most 3 added by policy a day and 10 in 30 days | Runaway additions, a compromised sponsor | The first checks failing refuse the request. An untrusted-yet sponsor, a fingerprint pinned elsewhere, or a limit reached **hold the request for people**: a pending licence in Warden's approval queue, approved by two people at 3AM, finishing the same way. A request is never refused just for being unusual, and never granted for it either. ## Six digits on two screens The six digits are the first 20 bits of a hash of the request itself. Swap the request on its way between the two consoles and the digits change, and a person sees it before anything is signed. To fool them, an attacker would need a second request with the same 20 bits, each attempt costing a signature with the new install's key and a fresh proof of work, while the person types the digits from the real screen. ## The install log Every addition and removal is a link in a hash chain per contract: the fingerprint and purpose, which install vouched, the request's hash, and the hash of the link before. Every licence Warden signs carries the chain's head and its latest twelve links. * 3AM checks each new licence against the head it last saw. A licence whose history doesn't carry on from it is refused: two different histories were signed. * Keychain members compare heads with their home at every sync, so two installs shown different histories both raise it (`security.install_log_fork`). * Keychain → Installs shows the history: who was added, when, and which install vouched for each. ## Audit events In 3AM: `licence.install_vouched`, `licence.install_removal`, `config.licence_candidate`, `security.install_code_mismatch`, `security.install_log_fork`. In Warden: `install.added`, `install.held`, `install.removed`, `install.refused`, `install.key_mismatch`.