diff --git a/model/model.go b/model/model.go
index 14a3e02..c1351f2 100644
--- a/model/model.go
+++ b/model/model.go
@@ -82,6 +82,10 @@ type Site struct {
 
 	Tags []string `json:"tags,omitempty"` // labels for grouping and filtering in the dashboard
 
+	// What the agent last said about its SSH server (see SiteReport.SSH and SSHRelay).
+	SSH      string `json:"ssh,omitempty"`
+	SSHRelay bool   `json:"sshRelay,omitempty"`
+
 	TunnelIP  string `json:"tunnelIp,omitempty"`  // the site's address inside the tunnel network
 	PublicKey string `json:"publicKey,omitempty"` // WireGuard public key, reported by the agent
 
@@ -462,6 +466,11 @@ type SiteConfig struct {
 	Edges    []EdgeRef `json:"edges"`
 	UpdateID string    `json:"updateId,omitempty"` // an administrator asked this agent to update itself now; echoed back in its report
 
+	// Terminals lists terminal sessions waiting for this agent. For each, the agent opens a connection
+	// to hammerhead at /site/terminal/<id> and joins it to its own SSH server, so a shell can be opened
+	// from the dashboard without any port being open on an edge.
+	Terminals []string `json:"terminals,omitempty"`
+
 	MailEgress []MailSpec `json:"mailEgress"`
 }
 
@@ -476,6 +485,10 @@ type SiteReport struct {
 	AutoUpdate bool                `json:"autoUpdate,omitempty"`
 	UpdateMsg  string              `json:"updateMsg,omitempty"`
 	UpdateID   string              `json:"updateId,omitempty"`
+	// SSH is where this machine's SSH server listens ("" when it is not running). SSHRelay says this
+	// agent can answer SiteConfig.Terminals, which is how an agent that is too old to relay shows itself.
+	SSH      string `json:"ssh,omitempty"`
+	SSHRelay bool   `json:"sshRelay,omitempty"`
 	// progress of that update, for the dashboard's progress bar and log
 	UpdateStage string   `json:"updateStage,omitempty"`
 	UpdatePct   int      `json:"updatePct,omitempty"`