fix: instance completions use server.name, smart attach/detach

- Instances have no name field — use server.name for completions
- attach-server: show only servers NOT in the project
- detach-server: show only servers IN the project
- Add helper functions for project-aware server completion
- 5 new tests covering all three fixes

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

completions/mcpctl.fish

@@ -72,7 +72,12 @@ function __mcpctl_resource_names
     if test -z "$resource"
         return
     end
-    mcpctl get $resource -o json 2>/dev/null | jq -r '.[][].name' 2>/dev/null
+    # Instances don't have a name field — use server.name instead
+    if test "$resource" = "instances"
+        mcpctl get instances -o json 2>/dev/null | jq -r '.[][].server.name' 2>/dev/null
+    else
+        mcpctl get $resource -o json 2>/dev/null | jq -r '.[][].name' 2>/dev/null
+    end
 end
 
 # Fetch project names for --project value
@@ -80,6 +85,43 @@ function __mcpctl_project_names
     mcpctl get projects -o json 2>/dev/null | jq -r '.[][].name' 2>/dev/null
 end
 
+# Helper: get the --project value from the command line
+function __mcpctl_get_project_value
+    set -l tokens (commandline -opc)
+    for i in (seq (count $tokens))
+        if test "$tokens[$i]" = "--project"; and test $i -lt (count $tokens)
+            echo $tokens[(math $i + 1)]
+            return
+        end
+    end
+end
+
+# Servers currently attached to the project (for detach-server)
+function __mcpctl_project_servers
+    set -l proj (__mcpctl_get_project_value)
+    if test -z "$proj"
+        return
+    end
+    mcpctl --project $proj get servers -o json 2>/dev/null | jq -r '.[][].name' 2>/dev/null
+end
+
+# Servers NOT attached to the project (for attach-server)
+function __mcpctl_available_servers
+    set -l proj (__mcpctl_get_project_value)
+    if test -z "$proj"
+        # No project — show all servers
+        mcpctl get servers -o json 2>/dev/null | jq -r '.[][].name' 2>/dev/null
+        return
+    end
+    set -l all (mcpctl get servers -o json 2>/dev/null | jq -r '.[][].name' 2>/dev/null)
+    set -l attached (mcpctl --project $proj get servers -o json 2>/dev/null | jq -r '.[][].name' 2>/dev/null)
+    for s in $all
+        if not contains -- $s $attached
+            echo $s
+        end
+    end
+end
+
 # --project value completion
 complete -c mcpctl -l project -xa '(__mcpctl_project_names)'
 
@@ -117,6 +159,12 @@ complete -c mcpctl -n "__fish_seen_subcommand_from edit; and __mcpctl_needs_reso
 # Resource names — after resource type is selected
 complete -c mcpctl -n "__fish_seen_subcommand_from get describe delete edit; and not __mcpctl_needs_resource_type" -a '(__mcpctl_resource_names)' -d 'Resource name'
 
+# attach-server: show servers NOT in the project
+complete -c mcpctl -n "__fish_seen_subcommand_from attach-server" -a '(__mcpctl_available_servers)' -d 'Server'
+
+# detach-server: show servers IN the project
+complete -c mcpctl -n "__fish_seen_subcommand_from detach-server" -a '(__mcpctl_project_servers)' -d 'Server'
+
 # get/describe options
 complete -c mcpctl -n "__fish_seen_subcommand_from get" -s o -l output -d 'Output format' -xa 'table json yaml'
 complete -c mcpctl -n "__fish_seen_subcommand_from describe" -s o -l output -d 'Output format' -xa 'detail json yaml'