diff --git a/actions/setup/js/mount_mcp_as_cli.cjs b/actions/setup/js/mount_mcp_as_cli.cjs
index 81702623441..ffaeba68818 100644
--- a/actions/setup/js/mount_mcp_as_cli.cjs
+++ b/actions/setup/js/mount_mcp_as_cli.cjs
@@ -311,6 +311,16 @@ exec node "${safeBridge}" \\
 `;
 }
 
+/**
+ * Format mounted server names into prompt-ready bullet lines.
+ *
+ * @param {string[]} mountedServers - Successfully mounted server names
+ * @returns {string}
+ */
+function formatMountedServersPromptList(mountedServers) {
+  return mountedServers.map(name => `- \`${name}\` — run \`${name} --help\` to see available tools`).join("\n");
+}
+
 /**
  * Mount MCP servers as CLI tools by reading the manifest and generating wrapper scripts.
  *
@@ -445,6 +455,7 @@ async function main() {
   }
   core.info(`CLI bin directory added to PATH: ${CLI_BIN_DIR}`);
   core.setOutput("mounted-servers", mountedServers.join(","));
+  core.setOutput("mounted-servers-list", formatMountedServersPromptList(mountedServers));
 }
 
-module.exports = { main, fetchMCPTools, generateCLIWrapperScript, isValidServerName, shellEscapeDoubleQuoted, parseMCPResponseBody };
+module.exports = { main, fetchMCPTools, generateCLIWrapperScript, isValidServerName, shellEscapeDoubleQuoted, parseMCPResponseBody, formatMountedServersPromptList };
diff --git a/actions/setup/js/mount_mcp_as_cli.test.cjs b/actions/setup/js/mount_mcp_as_cli.test.cjs
index cd86c1f53be..233858cce08 100644
--- a/actions/setup/js/mount_mcp_as_cli.test.cjs
+++ b/actions/setup/js/mount_mcp_as_cli.test.cjs
@@ -1,7 +1,7 @@
 // @ts-check
 import { describe, expect, it } from "vitest";
 
-import { parseMCPResponseBody } from "./mount_mcp_as_cli.cjs";
+import { formatMountedServersPromptList, parseMCPResponseBody } from "./mount_mcp_as_cli.cjs";
 
 describe("mount_mcp_as_cli.cjs", () => {
   it("parses JSON object responses unchanged", () => {
@@ -38,4 +38,9 @@ describe("mount_mcp_as_cli.cjs", () => {
       },
     });
   });
+
+  it("formats mounted servers for prompt rendering", () => {
+    expect(formatMountedServersPromptList(["safeoutputs", "playwright"])).toBe("- `safeoutputs` — run `safeoutputs --help` to see available tools\n- `playwright` — run `playwright --help` to see available tools");
+    expect(formatMountedServersPromptList([])).toBe("");
+  });
 });
diff --git a/pkg/workflow/mcp_cli_mount.go b/pkg/workflow/mcp_cli_mount.go
index 92008009f34..260bed34349 100644
--- a/pkg/workflow/mcp_cli_mount.go
+++ b/pkg/workflow/mcp_cli_mount.go
@@ -297,28 +297,22 @@ func GetMCPCLIPathSetup(data *WorkflowData) string {
 	return `export PATH="${RUNNER_TEMP}/gh-aw/mcp-cli/bin:$PATH"`
 }
 
-// buildMCPCLIPromptSection returns a PromptSection describing the CLI tools available
-// to the agent, or nil if there are no servers to mount.
-// The prompt is loaded from actions/setup/md/mcp_cli_tools_prompt.md at runtime,
-// with the __GH_AW_MCP_CLI_SERVERS_LIST__ placeholder substituted by the substitution step.
+// buildMCPCLIPromptSection returns a PromptSection describing CLI wrappers available
+// to the agent, or nil if no servers are configured for mounting.
+// The prompt content is loaded from actions/setup/md/mcp_cli_tools_prompt.md at runtime.
+// The server list comes from the mount step output so only successfully mounted wrappers
+// are advertised to the model.
 func buildMCPCLIPromptSection(data *WorkflowData) *PromptSection {
 	servers := getMCPCLIServerNames(data)
 	if len(servers) == 0 {
 		return nil
 	}
 
-	// Build the human-readable list of servers with example usage
-	var listLines []string
-	for _, name := range servers {
-		listLines = append(listLines, fmt.Sprintf("- `%s` — run `%s --help` to see available tools", name, name))
-	}
-	serversList := strings.Join(listLines, "\n")
-
 	return &PromptSection{
 		Content: mcpCLIToolsPromptFile,
 		IsFile:  true,
 		EnvVars: map[string]string{
-			"GH_AW_MCP_CLI_SERVERS_LIST": serversList,
+			"GH_AW_MCP_CLI_SERVERS_LIST": "${{ steps.mount-mcp-clis.outputs.mounted-servers-list }}",
 		},
 	}
 }
diff --git a/pkg/workflow/mcp_cli_mount_test.go b/pkg/workflow/mcp_cli_mount_test.go
index 205cfa178b5..207ca774742 100644
--- a/pkg/workflow/mcp_cli_mount_test.go
+++ b/pkg/workflow/mcp_cli_mount_test.go
@@ -226,4 +226,5 @@ func TestBuildMCPCLIPromptSection_PromptFileUsesNonHeadingLabels(t *testing.T) {
 	assert.NotRegexp(t, `(?m)^\s*(>\s*)?##\s+`, prompt, "prompt must not contain H2 Markdown headings")
 	assert.NotRegexp(t, `(?m)^\s*(>\s*)?###\s+`, prompt, "prompt must not contain H3 Markdown headings")
 	assert.Contains(t, prompt, "Use `<server> --help` for tool names, parameters, and examples before calling any command.")
+	assert.Equal(t, "${{ steps.mount-mcp-clis.outputs.mounted-servers-list }}", section.EnvVars["GH_AW_MCP_CLI_SERVERS_LIST"])
 }