diff --git a/backend/windmill-worker/src/ai_executor.rs b/backend/windmill-worker/src/ai_executor.rs
index 456a34fcb0..a995864bf9 100644
--- a/backend/windmill-worker/src/ai_executor.rs
+++ b/backend/windmill-worker/src/ai_executor.rs
@@ -276,16 +276,12 @@ fn narrow_roster(
                 .is_some_and(|s| enabled.iter().any(|n| n == s));
             match &t.value {
                 ToolValue::Mcp(mcp) => {
-                    // An MCP entry is added with no summary and the roster displays it by its
-                    // resource path, so that path is the only name the form can offer for it. Match
-                    // it too, or naming one tool would be the sole way to keep a whole server.
-                    // Both sides are stripped: the roster stores the path as authored, so the name
-                    // the picker offers carries the `$res:` prefix while `McpToolSource` does not.
+                    // An MCP entry is added with no summary and shows as its resource path, so that
+                    // path is the only name the form can offer for the server as a whole. It is
+                    // matched bare: a name carrying the `$res:` the roster stores would be resolved
+                    // to the resource itself before the worker is handed its args.
                     let path = mcp.resource_path.trim_start_matches("$res:");
-                    let named = named
-                        || enabled
-                            .iter()
-                            .any(|n| n.trim_start_matches("$res:") == path);
+                    let named = named || enabled.iter().any(|n| n == path);
                     if named {
                         enabled_mcp_paths.insert(path.to_string());
                     }
@@ -329,12 +325,7 @@ fn unmatched_enabled_tools_message(
     let unmatched: Vec<&str> = enabled_tools
         .iter()
         .map(|name| name.as_str())
-        // An MCP server is named by the path the roster shows, which carries the `$res:` the
-        // matched paths are stripped of, so the two are compared without it.
-        .filter(|name| {
-            let bare = name.trim_start_matches("$res:");
-            !advertised.iter().any(|a| a == name || *a == bare)
-        })
+        .filter(|name| !advertised.contains(name))
         .collect();
     if unmatched.is_empty() {
         return None;
@@ -2067,30 +2058,19 @@ mod tests {
         assert_eq!(names(&kept), ["github"]);
         assert!(paths.is_empty());
 
-        // An MCP entry is added with no summary, and the form offers it by the path the roster
-        // displays it as. Without this the only way to keep such a server would be naming one of
-        // the tools it has not been asked for yet.
-        let unnamed = || {
-            vec![AgentTool {
-                summary: None,
-                ..mcp("c", "github", "$res:u/test/gh")
-            }]
-        };
-        let (kept, paths) = narrow_roster(unnamed(), Some(&["u/test/gh".to_string()]));
-        assert_eq!(kept.len(), 1);
-        assert_eq!(paths.into_iter().collect::<Vec<_>>(), ["u/test/gh"]);
-        let (dropped, paths) = narrow_roster(unnamed(), Some(&["u/test/other".to_string()]));
-        assert!(dropped.is_empty());
-        assert!(paths.is_empty());
-
-        // The roster stores the path as authored, so the name the picker offers is the `$res:` form
-        // while the loader's own key is not — a run that selects a server from the form sends this.
-        let selected = ["$res:u/test/gh".to_string()];
-        let (kept, paths) = narrow_roster(unnamed(), Some(&selected));
+        // An MCP entry is added with no summary, and the form names it by its resource path, bare.
+        // Without this the only way to keep such a server would be naming one of the tools it has
+        // not been asked for yet.
+        let unnamed = || vec![AgentTool { summary: None, ..mcp("c", "github", "$res:u/test/gh") }];
+        let named_server = ["u/test/gh".to_string()];
+        let (kept, paths) = narrow_roster(unnamed(), Some(&named_server));
         assert_eq!(kept.len(), 1);
         assert_eq!(paths.into_iter().collect::<Vec<_>>(), ["u/test/gh"]);
         // And having matched, it is not reported as having named nothing.
-        assert!(unmatched_enabled_tools_message(&selected, &["u/test/gh"]).is_none());
+        assert!(unmatched_enabled_tools_message(&named_server, &["u/test/gh"]).is_none());
+        let (dropped, paths) = narrow_roster(unnamed(), Some(&["u/test/other".to_string()]));
+        assert!(dropped.is_empty());
+        assert!(paths.is_empty());
     }
 
     /// The two sides of the server-entry match are different types, and getting it wrong advertises
diff --git a/frontend/src/lib/components/flows/agentToolUtils.ts b/frontend/src/lib/components/flows/agentToolUtils.ts
index c46868c46e..44600ea1bd 100644
--- a/frontend/src/lib/components/flows/agentToolUtils.ts
+++ b/frontend/src/lib/components/flows/agentToolUtils.ts
@@ -99,6 +99,16 @@ export function toolDisplayName(tool: AgentTool): string | undefined {
 	return tool?.summary || value?.path || value?.resource_path || undefined
 }
 
+/** The name `enabled_tools` holds a tool by, which is what the roster shows it as except for an MCP
+ *  server displayed by the resource path it was authored with: a name carrying that `$res:` is
+ *  resolved to the resource's own value before the step runs, so it would reach the worker as an
+ *  object where a name is expected and fail the step outright. */
+export function toolEnabledName(tool: AgentTool): string | undefined {
+	const name = toolDisplayName(tool)
+	const value = tool?.value as Record<string, any>
+	return name && name === value?.resource_path ? name.replace(/^\$res:/, '') : name
+}
+
 /**
  * Create an AI Agent tool (nested agent)
  */
diff --git a/frontend/src/lib/components/flows/content/AiAgentStepInputs.svelte b/frontend/src/lib/components/flows/content/AiAgentStepInputs.svelte
index da78d2d50f..b9643334e9 100644
--- a/frontend/src/lib/components/flows/content/AiAgentStepInputs.svelte
+++ b/frontend/src/lib/components/flows/content/AiAgentStepInputs.svelte
@@ -46,7 +46,7 @@
 	import { Plus, X } from 'lucide-svelte'
 	import type { PickableProperties } from '../previousResults'
 	import type { FlowCopilotContext } from '$lib/components/copilot/flow'
-	import { toolDisplayName, type AgentTool } from '../agentToolUtils'
+	import { toolEnabledName, type AgentTool } from '../agentToolUtils'
 	import {
 		AGENT_FIELDS,
 		AGENT_FIELD_GROUPS,
@@ -168,15 +168,11 @@
 	// field's shape from; `flowInfers` hands every step its own copy, so this stays this step's.
 	// A linked step gets the resource's roster here, which is the one it narrows.
 	$effect(() => {
-		// By the name the roster shows, not the summary alone: an MCP entry is added without one and
-		// displays as its resource path, so keying on `summary` would leave a whole server with no
-		// name to pick. `narrow_roster` matches that path for the same reason.
-		//
-		// Stripped of `$res:`, which the roster keeps: a static input transform holding one is
-		// resolved to the resource's own value before the step runs, so the prefixed form would
-		// reach the worker as an object where a name is expected, and the step would fail outright.
+		// By what each tool is named, not the summary alone: an MCP entry is added without one and is
+		// named by its resource path, so keying on `summary` would leave a whole server with no name
+		// to pick. `narrow_roster` matches that path for the same reason.
 		const names = tools
-			.map((tool) => toolDisplayName(tool)?.replace(/^\$res:/, ''))
+			.map((tool) => toolEnabledName(tool))
 			.filter((name): name is string => !!name)
 		const properties = schemaProperties
 		untrack(() => {