Show the default team channel location

internal/api/queries/team.graphql

@@ -1400,3 +1400,15 @@ mutation TeamStopSignalLift($appRef: String!, $id: ID!) {
     signal { ...StopSignalFields }
   }
 }
+
+# Default-channel identity only, no transcript/cursor read or cursor mutation.
+query TeamChannelLocation($appRef: ID!) {
+  app(ref: $appRef) {
+    id
+    urn
+    defaultChannel {
+      id
+      chatRootNodeId
+    }
+  }
+}

internal/cmd/agentic/agentic-usage.md

@@ -3460,3 +3460,17 @@ format delegates the provider default. No local output-file or remote document
 creation option. Server delegates format/binary/size guarantees to its tool;
 file_too_large and unknown failures retain existing error mapping/refusal text,
 with no retry/reconnect guess. No hidden discovery, writes or uploads.
+
+## Default team channel location (#489)
+
+`hadron team channel [--app <ref>]` answers where the default team channel lives.
+It uses the existing team App resolution (--app, configured context, binding),
+reports that source, and copies the server-built URL verbatim. The destination
+is the channel root node's own page and channel view, not an App conversation
+selector. No route is composed. JSON is {app,appSource,channelId,portalUrl};
+portalUrl is present and nullable. Text prints URL: only when supplied, otherwise
+says no channel URL is available. One metadata read and one best-effort authorized
+root node read, no transcript fetch or cursor/binding write. The root read records
+a read and may decrypt internally. A concealed/missing/failed root read leaves
+the URL null; initial lookup failures remain errors. Existing channel get/list
+commands are unchanged.

internal/cmd/team/channel_location.go

@@ -0,0 +1,85 @@
+package team
+
+import (
+	"fmt"
+	"io"
+
+	"github.com/hadron-memory/hadron-cli/internal/api"
+	"github.com/hadron-memory/hadron-cli/internal/api/gen"
+	"github.com/hadron-memory/hadron-cli/internal/cmdutil"
+	"github.com/hadron-memory/hadron-cli/internal/exitcode"
+	"github.com/hadron-memory/hadron-cli/internal/output"
+	"github.com/spf13/cobra"
+)
+
+type teamChannelLocationDTO struct {
+	App       string  `json:"app"`
+	AppSource string  `json:"appSource"`
+	ChannelID string  `json:"channelId"`
+	PortalURL *string `json:"portalUrl"`
+}
+
+func newCmdTeamChannel(f *cmdutil.Factory) *cobra.Command {
+	return &cobra.Command{
+		Use: "channel", Short: "Show the default team channel's server-built URL",
+		Long: `Find the default team channel without knowing its id or address.
+
+The team App resolves from --app, the configured App context, or the worktree
+binding, just as other team commands do. Output names the App and scope source.
+The server-built URL opens the channel root node's own page and channel view;
+this does not select an App-level conversation or create a new portal route.
+
+One default-channel metadata read is followed by one authorized root-node read
+for identity and URL only. That node read records a read and may decrypt
+internally; no transcript is fetched, no cursor is advanced, and no binding
+is started or changed. No URL is composed by the client. If the server supplies
+no link, or the optional root read fails or is concealed, portalUrl is null in
+JSON and text says no channel URL is available. The default-channel lookup
+itself must succeed.`,
+		Example: "  hadron team channel\n  hadron team channel --app acme.com:team --json",
+		Args:    cobra.NoArgs,
+		RunE: func(cmd *cobra.Command, _ []string) error {
+			ctx := cmd.Context()
+			b, err := readBindingOrNilWithApp(ctx, f)
+			if err != nil {
+				return err
+			}
+			scope, err := resolveTeamAppScope(ctx, f, b)
+			if err != nil {
+				return err
+			}
+			client, err := f.GraphQLClient()
+			if err != nil {
+				return err
+			}
+			resp, err := gen.TeamChannelLocation(ctx, client, scope.Ref)
+			if err != nil {
+				return api.MapError(err)
+			}
+			if resp.App == nil {
+				return exitcode.Newf(exitcode.NotFound, "no team App is readable here")
+			}
+			if resp.App.DefaultChannel == nil {
+				return exitcode.Newf(exitcode.NotFound, "the App has no default team channel")
+			}
+			d := teamChannelLocationDTO{App: resp.App.Urn, AppSource: scope.Source, ChannelID: resp.App.DefaultChannel.Id}
+			if ref := resp.App.DefaultChannel.ChatRootNodeId; ref != "" {
+				pointer, pointerErr := gen.NodePortal(ctx, client, ref)
+				if pointerErr == nil && pointer != nil && pointer.Node != nil {
+					d.PortalURL = pointer.Node.PortalUrl
+				}
+			}
+			return output.Write(f.IOStreams, f.JSON, d, func(w io.Writer) error {
+				if _, err := fmt.Fprintf(w, "app: %s (%s)\nchannel: %s\n", d.App, d.AppSource, d.ChannelID); err != nil {
+					return err
+				}
+				if d.PortalURL != nil {
+					_, err := fmt.Fprintf(w, "URL: %s\n", *d.PortalURL)
+					return err
+				}
+				_, err := fmt.Fprintln(w, "no channel URL is available")
+				return err
+			})
+		},
+	}
+}

internal/cmd/team/team.go

@@ -97,6 +97,7 @@ and ` + "`hadron app agent list <app>`" + ` (the installed cast pool).`,
 	cmd.AddCommand(newCmdRole(f))
 	cmd.AddCommand(newCmdSession(f))
 	cmd.AddCommand(newCmdTeamChat(f))
+	cmd.AddCommand(newCmdTeamChannel(f))
 	cmd.AddCommand(newCmdAttention(f))
 	cmd.AddCommand(newCmdTeamTask(f))
 	cmd.AddCommand(newCmdTeamRoster(f))