Offer the development server and the browser to LLM nodes

A flow could write software but never run it: the coding agent edits files and
that is where it ended. These two entries close the loop - start the code the
execution wrote, then open it in a browser and read what the page says.

Both are streamable-http, so an LLM node binds them with no new Java: the
retriever already filtered the catalogue by transport and the draft normalizer
already dropped unknown servers. The development server's preview is pinned to
the execution with x-preview-key, the way the coding agent's workspace already
is, so the scope travels in a header the service fills in rather than in an
argument a model could choose for itself.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

src/main/resources/mcp-servers.json

@@ -122,6 +122,83 @@
           }
         }
       }
+    },
+    {
+      "id": "dev-server-mcp",
+      "name": "Development Server MCP Server",
+      "description": "Starts and observes preconfigured development services. One instance per execution, in a throwaway copy of that execution's workspace, each on its own port. The caller chooses a service id and nothing else: commands, arguments and directories belong to the operator.",
+      "transport": "streamable-http",
+      "url": "${{host}}/dev-server/mcp",
+      "headers": {
+        "Authorization": "Bearer ${{key}}",
+        "x-preview-key": "${{context.rootExecutionId}}"
+      },
+      "configurationSchema": {
+        "type": "object",
+        "additionalProperties": false,
+        "required": ["host", "key"],
+        "properties": {
+          "host": {
+            "type": "string",
+            "title": "Host",
+            "description": "Base host for the development server MCP endpoint, including scheme and without a trailing slash.",
+            "examples": ["https://host.it"],
+            "minLength": 1
+          },
+          "key": {
+            "type": "string",
+            "title": "API Key",
+            "description": "Bearer token used to authorize requests to the development server MCP server.",
+            "format": "password",
+            "writeOnly": true,
+            "minLength": 1,
+            "x-ui-bindable-as-input": true,
+            "x-ui-binding-static-label": "static value",
+            "x-ui-binding-input-label": "node input",
+            "x-ui-input-name": "key",
+            "x-ui-input-type": "TEXT",
+            "x-ui-input-multiple": false
+          }
+        }
+      }
+    },
+    {
+      "id": "browser-mcp",
+      "name": "Browser MCP Server",
+      "description": "Drives a headless browser against the origins its operator allows, and reports what the page says: text snapshots, console messages and network errors. Screenshots are taken but a text-only caller receives a placeholder, not the image.",
+      "transport": "streamable-http",
+      "url": "${{host}}/browser/mcp",
+      "headers": {
+        "Authorization": "Bearer ${{key}}"
+      },
+      "configurationSchema": {
+        "type": "object",
+        "additionalProperties": false,
+        "required": ["host", "key"],
+        "properties": {
+          "host": {
+            "type": "string",
+            "title": "Host",
+            "description": "Base host for the browser MCP endpoint, including scheme and without a trailing slash.",
+            "examples": ["https://host.it"],
+            "minLength": 1
+          },
+          "key": {
+            "type": "string",
+            "title": "API Key",
+            "description": "Bearer token used to authorize requests to the browser MCP server.",
+            "format": "password",
+            "writeOnly": true,
+            "minLength": 1,
+            "x-ui-bindable-as-input": true,
+            "x-ui-binding-static-label": "static value",
+            "x-ui-binding-input-label": "node input",
+            "x-ui-input-name": "key",
+            "x-ui-input-type": "TEXT",
+            "x-ui-input-multiple": false
+          }
+        }
+      }
     }
   ]
 }

src/test/java/it/cnr/isti/workflow/manager/controllers/RetrieverControllerTest.java

@@ -49,10 +49,27 @@ public class RetrieverControllerTest {
         List<String> values = retrieverController.getValues("MCPServers", "streamableHttpServers", Map.of());
 
         assertTrue(values.contains("coding-agent-mcp"));
+        // The three that make a development loop: write the code, run it, look at it in a browser.
+        assertTrue(values.contains("dev-server-mcp"));
+        assertTrue(values.contains("browser-mcp"));
         assertFalse(values.contains("postgres"));
         assertFalse(values.contains("url-downloader"));
     }
 
+    @Test
+    public void pinsTheDevServerPreviewToTheExecutionThatAskedForIt() {
+        // The key names a scope the model may not choose for itself, so it travels as a header the
+        // service fills in - the same way the coding agent's workspace is pinned. A tool argument
+        // would let one execution ask for another's preview by name.
+        MCPServersProvider.MCPServerDefinition devServer = mcpServersProvider.getServers().stream()
+                .filter(server -> "dev-server-mcp".equals(server.id()))
+                .findFirst()
+                .orElseThrow();
+
+        assertEquals("${{context.rootExecutionId}}", devServer.headers().get("x-preview-key"));
+        assertEquals("streamable-http", devServer.transport());
+    }
+
     @Test
     public void llmModelsAreOpenForAProviderThatCannotListThem() {
         // Gemini's catalogue is not listable without a credential and its names move constantly, so