web-debug-mcp

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Close web debug session

web_session_close

DestructiveIdempotent

Close an active browser debugging session and release all associated browser resources to free memory and avoid lingering connections.

Instructions

Close the selected session and release any browser resources owned by it.

Input Schema

TableJSON Schema

Name	Required	Description	Default
`sessionId`	Yes
`artifactPolicy`	No		retain

Output Schema

TableJSON Schema

Name	Required	Description	Default
`ok`	Yes
`data`	No
`error`	No
`warnings`	Yes
`artifacts`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

Changed9 schema fields changedv0.10.0Sep 8, 2026

addedOutput schema / definitions / BrowserRuntimeCapabilitiesOutput

Added value: +{
+  "additionalProperties": false,
+  "properties": {
+    "accessibility": {
+      "$ref": "#/definitions/RuntimeCapabilityOutput"
+    },
+    "actions": {
+      "$ref": "#/definitions/RuntimeCapabilityOutput"
+    },
+    "authSeeding": {
+      "$ref": "#/definitions/RuntimeCapabilityOutput"
+    },
+    "browser": {
+      "enum": [
+        "chromium",
+        "safari"
+      ],
+      "type": "string"
+    },
+    "console": {
+      "$ref": "#/definitions/RuntimeCapabilityOutput"
+    },
+    "dom": {
+      "$ref": "#/definitions/RuntimeCapabilityOutput"
+    },
+    "evaluation": {
+      "$ref": "#/definitions/RuntimeCapabilityOutput"
+    },
+    "javascriptDebugger": {
+      "$ref": "#/definitions/RuntimeCapabilityOutput"
+    },
+    "locators": {
+      "additionalProperties": false,
+      "properties": {
+        "css": {
+          "$ref": "#/definitions/RuntimeCapabilityOutput"
+        },
+        "semantic": {
+          "$ref": "#/definitions/RuntimeCapabilityOutput"
+        }
+      },
+      "required": [
+        "css",
+        "semantic"
+      ],
+      "type": "object"
+    },
+    "network": {
+      "$ref": "#/definitions/RuntimeCapabilityOutput"
+    },
+    "pageRuntimeEnrichment": {
+      "$ref": "#/definitions/RuntimeCapabilityOutput"
+    },
+    "schemaVersion": {
+      "const": 2,
+      "type": "number"
+    },
+    "screenshots": {
+      "$ref": "#/definitions/RuntimeCapabilityOutput"
+    },
+    "tlsBypass": {
+      "$ref": "#/definitions/RuntimeCapabilityOutput"
+    },
+    "transport": {
+      "enum": [
+        "chromium-launch",
+        "chromium-cdp-attach",
+        "safari-webdriver"
+      ],
+      "type": "string"
+    },
+    "viewportMatrix": {
+      "$ref": "#/definitions/RuntimeCapabilityOutput"
+    },
+    "webmcp": {
+      "$ref": "#/definitions/RuntimeCapabilityOutput"
+    }
+  },
+  "required": [
+    "schemaVersion",
+    "browser",
+    "transport",
+    "actions",
+    "locators",
+    "dom",
+    "console",
+    "network",
+    "screenshots",
+    "javascriptDebugger",
+    "evaluation",
+    "accessibility",
+    "pageRuntimeEnrichment",
+    "viewportMatrix",
+    "tlsBypass",
+    "authSeeding",
+    "webmcp"
+  ],
+  "type": "object"
+}

addedOutput schema / definitions / DebugSessionSummaryOutput

Added value: +{
+  "additionalProperties": false,
+  "properties": {
+    "artifactDir": {
+      "maxLength": 4096,
+      "type": "string"
+    },
+    "artifactState": {
+      "enum": [
+        "retained",
+        "deleted"
+      ],
+      "type": "string"
+    },
+    "authFixture": {
+      "enum": [
+        "seeded-disposable",
+        "none"
+      ],
+      "type": "string"
+    },
+    "createdAt": {
+      "maxLength": 100,
+      "type": "string"
+    },
+    "id": {
+      "format": "uuid",
+      "pattern": "^([0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[1-8][0-9a-fA-F]{3}-[89abAB][0-9a-fA-F]{3}-[0-9a-fA-F]{12}|00000000-0000-0000-0000-000000000000|ffffffff-ffff-ffff-ffff-ffffffffffff)$",
+      "type": "string"
+    },
+    "projectCapabilities": {
+      "$ref": "#/definitions/ProjectCapabilitiesOutput"
+    },
+    "projectRoot": {
+      "maxLength": 4096,
+      "type": "string"
+    },
+    "runtimeCapabilities": {
+      "anyOf": [
+        {
+          "$ref": "#/definitions/BrowserRuntimeCapabilitiesOutput"
+        },
+        {
+          "type": "null"
+        }
+      ]
+    },
+    "schemaVersion": {
+      "const": 3,
+      "type": "number"
+    },
+    "status": {
+      "enum": [
+        "starting",
+        "ready",
+        "paused",
+        "failed",
+        "closed"
+      ],
+      "type": "string"
+    },
+    "target": {
+      "anyOf": [
+        {
+          "additionalProperties": false,
+          "properties": {
+            "browser": {
+              "enum": [
+                "chromium",
+                "safari"
+              ],
+              "type": "string"
+            },
+            "isolated": {
+              "type": "boolean"
+            },
+            "isolation": {
+              "additionalProperties": false,
+              "properties": {
+                "browserProcess": {
+                  "type": "boolean"
+                },
+                "cache": {
+                  "type": "boolean"
+                },
+                "context": {
+                  "type": "boolean"
+                },
+                "navigation": {
+                  "type": "boolean"
+                },
+                "profile": {
+                  "type": "boolean"
+                },
+                "serverState": {
+                  "type": "boolean"
+                },
+                "serviceWorkers": {
+                  "type": "boolean"
+                },
+                "storage": {
+                  "type": "boolean"
+                }
+              },
+              "required": [
+                "browserProcess",
+                "context",
+                "profile",
+                "storage",
+                "cache",
+                "serviceWorkers",
+                "navigation",
+                "serverState"
+              ],
+              "type": "object"
+            },
+            "mode": {
+              "enum": [
+                "launch",
+                "attach",
+                "webdriver"
+              ],
+              "type": "string"
+            },
+            "remote": {
+              "type": "boolean"
+            },
+            "schemaVersion": {
+              "const": 1,
+              "type": "number"
+            },
+            "targetId": {
+              "maxLength": 200,
+              "type": "string"
+            },
+            "title": {
+              "maxLength": 300,
+              "type": "string"
+            },
+            "url": {
+              "maxLength": 2560,
+              "type": "string"
+            },
+            "viewport": {
+              "anyOf": [
+                {
+                  "additionalProperties": false,
+                  "properties": {
+                    "height": {
+                      "maximum": 9007199254740991,
+                      "minimum": -9007199254740991,
+                      "type": "integer"
+                    },
+                    "width": {
+                      "maximum": 9007199254740991,
+                      "minimum": -9007199254740991,
+                      "type": "integer"
+                    }
+                  },
+                  "required": [
+                    "width",
+                    "height"
+                  ],
+                  "type": "object"
+                },
+                {
+                  "type": "null"
+                }
+              ]
+            }
+          },
+          "required": [
+            "schemaVersion",
+            "browser",
+            "remote",
+            "url",
+            "title",
+            "viewport",
+            "isolated"
+          ],
+          "type": "object"
+        },
+        {
+          "type": "null"
+        }
+      ]
+    },
+    "tls": {
+      "enum": [
+        "strict",
+        "allow-insecure-loopback"
+      ],
+      "type": "string"
+    },
+    "url": {
+      "maxLength": 2560,
+      "type": "string"
+    },
+    "warnings": {
+      "items": {
+        "maxLength": 500,
+        "type": "string"
+      },
+      "maxItems": 100,
+      "type": "array"
+    }
+  },
+  "required": [
+    "schemaVersion",
+    "id",
+    "projectRoot",
+    "url",
+    "status",
+    "createdAt",
+    "artifactDir",
+    "target",
+    "projectCapabilities",
+    "runtimeCapabilities",
+    "warnings"
+  ],
+  "type": "object"
+}

addedOutput schema / definitions / ProjectCapabilitiesOutput

Added value: +{
+  "additionalProperties": false,
+  "properties": {
+    "angular": {
+      "type": "boolean"
+    },
+    "browserTarget": {
+      "type": "boolean"
+    },
+    "next": {
+      "type": "boolean"
+    },
+    "react": {
+      "type": "boolean"
+    },
+    "serverRuntime": {
+      "type": "boolean"
+    },
+    "vite": {
+      "type": "boolean"
+    },
+    "vue": {
+      "type": "boolean"
+    }
+  },
+  "required": [
+    "browserTarget",
+    "react",
+    "angular",
+    "vue",
+    "vite",
+    "next",
+    "serverRuntime"
+  ],
+  "type": "object"
+}

addedOutput schema / definitions / RuntimeCapabilityOutput

Added value: +{
+  "additionalProperties": false,
+  "properties": {
+    "provenance": {
+      "items": {
+        "enum": [
+          "playwright",
+          "chromium-cdp",
+          "safari-webdriver",
+          "safari-bidi",
+          "performance-resource-timing",
+          "session-policy",
+          "webmcp-page-api"
+        ],
+        "type": "string"
+      },
+      "maxItems": 2,
+      "type": "array"
+    },
+    "reason": {
+      "maxLength": 500,
+      "type": "string"
+    },
+    "state": {
+      "enum": [
+        "supported",
+        "degraded",
+        "unsupported"
+      ],
+      "type": "string"
+    }
+  },
+  "required": [
+    "state",
+    "provenance"
+  ],
+  "type": "object"
+}

removedOutput schema / properties / data / additionalProperties
```
Removed value: -false
```

addedOutput schema / properties / data / allOf

Added value: +[
+  {
+    "$ref": "#/definitions/DebugSessionSummaryOutput"
+  }
+]

removedOutput schema / properties / data / properties

Removed value: -{
-  "artifactDir": {
-    "maxLength": 4096,
-    "type": "string"
-  },
-  "artifactState": {
-    "enum": [
-      "retained",
-      "deleted"
-    ],
-    "type": "string"
-  },
-  "authFixture": {
-    "enum": [
-      "seeded-disposable",
-      "none"
-    ],
-    "type": "string"
-  },
-  "createdAt": {
-    "maxLength": 100,
-    "type": "string"
-  },
-  "id": {
-    "format": "uuid",
-    "pattern": "^([0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[1-8][0-9a-fA-F]{3}-[89abAB][0-9a-fA-F]{3}-[0-9a-fA-F]{12}|00000000-0000-0000-0000-000000000000|ffffffff-ffff-ffff-ffff-ffffffffffff)$",
-    "type": "string"
-  },
-  "projectCapabilities": {
-    "additionalProperties": false,
-    "properties": {
-      "angular": {
-        "type": "boolean"
-      },
-      "browserTarget": {
-        "type": "boolean"
-      },
-      "next": {
-        "type": "boolean"
-      },
-      "react": {
-        "type": "boolean"
-      },
-      "serverRuntime": {
-        "type": "boolean"
-      },
-      "vite": {
-        "type": "boolean"
-      },
-      "vue": {
-        "type": "boolean"
-      }
-    },
-    "required": [
-      "browserTarget",
-      "react",
-      "angular",
-      "vue",
-      "vite",
-      "next",
-      "serverRuntime"
-    ],
-    "type": "object"
-  },
-  "projectRoot": {
-    "maxLength": 4096,
-    "type": "string"
-  },
-  "runtimeCapabilities": {
-    "anyOf": [
-      {
-        "additionalProperties": false,
-        "properties": {
-          "accessibility": {
-            "additionalProperties": false,
-            "properties": {
-              "provenance": {
-                "items": {
-                  "enum": [
-                    "playwright",
-                    "chromium-cdp",
-                    "safari-webdriver",
-                    "safari-bidi",
-                    "performance-resource-timing",
-                    "session-policy",
-                    "webmcp-page-api"
-                  ],
-                  "type": "string"
-                },
-                "maxItems": 2,
-                "type": "array"
-              },
-              "reason": {
-                "maxLength": 500,
-                "type": "string"
-              },
-              "state": {
-                "enum": [
-                  "supported",
-                  "degraded",
-                  "unsupported"
-                ],
-                "type": "string"
-              }
-            },
-            "required": [
-              "state",
-              "provenance"
-            ],
-            "type": "object"
-          },
-          "actions": {
-            "additionalProperties": false,
-            "properties": {
-              "provenance": {
-                "items": {
-                  "enum": [
-                    "playwright",
-                    "chromium-cdp",
-                    "safari-webdriver",
-                    "safari-bidi",
-                    "performance-resource-timing",
-                    "session-policy",
-                    "webmcp-page-api"
-                  ],
-                  "type": "string"
-                },
-                "maxItems": 2,
-                "type": "array"
-              },
-              "reason": {
-                "maxLength": 500,
-                "type": "string"
-              },
-              "state": {
-                "enum": [
-                  "supported",
-                  "degraded",
-                  "unsupported"
-                ],
-                "type": "string"
-              }
-            },
-            "required": [
-              "state",
-              "provenance"
-            ],
-            "type": "object"
-          },
-          "authSeeding": {
-            "additionalProperties": false,
-            "properties": {
-              "provenance": {
-                "items": {
-                  "enum": [
-                    "playwright",
-                    "chromium-cdp",
-                    "safari-webdriver",
-                    "safari-bidi",
-                    "performance-resource-timing",
-                    "session-policy",
-                    "webmcp-page-api"
-                  ],
-                  "type": "string"
-                },
-                "maxItems": 2,
-                "type": "array"
-              },
-              "reason": {
-                "maxLength": 500,
-                "type": "string"
-              },
-              "state": {
-                "enum": [
-                  "supported",
-                  "degraded",
-                  "unsupported"
-                ],
-                "type": "string"
-              }
-            },
-            "required": [
-              "state",
-              "provenance"
-            ],
-            "type": "object"
-          },
-          "browser": {
-            "enum": [
-              "chromium",
-              "safari"
-            ],
-            "type": "string"
-          },
-          "console": {
-            "additionalProperties": false,
-            "properties": {
-              "provenance": {
-                "items": {
-                  "enum": [
-                    "playwright",
-                    "chromium-cdp",
-                    "safari-webdriver",
-                    "safari-bidi",
-                    "performance-resource-timing",
-                    "session-policy",
-                    "webmcp-page-api"
-                  ],
-                  "type": "string"
-                },
-                "maxItems": 2,
-                "type": "array"
-              },
-              "reason": {
-                "maxLength": 500,
-                "type": "string"
-              },
-              "state": {
-                "enum": [
-                  "supported",
-                  "degraded",
-                  "unsupported"
-                ],
-                "type": "string"
-              }
-            },
-            "required": [
-              "state",
-              "provenance"
-            ],
-            "type": "object"
-          },
-          "dom": {
-            "additionalProperties": false,
-            "properties": {
-              "provenance": {
-                "items": {
-                  "enum": [
-                    "playwright",
-                    "chromium-cdp",
-                    "safari-webdriver",
-                    "safari-bidi",
-                    "performance-resource-timing",
-                    "session-policy",
-                    "webmcp-page-api"
-                  ],
-                  "type": "string"
-                },
-                "maxItems": 2,
-                "type": "array"
-              },
-              "reason": {
-                "maxLength": 500,
-                "type": "string"
-              },
-              "state": {
-                "enum": [
-                  "supported",
-                  "degraded",
-                  "unsupported"
-                ],
-                "type": "string"
-              }
-            },
-            "required": [
-              "state",
-              "provenance"
-            ],
-            "type": "object"
-          },
-          "evaluation": {
-            "additionalProperties": false,
-            "properties": {
-              "provenance": {
-                "items": {
-                  "enum": [
-                    "playwright",
-                    "chromium-cdp",
-                    "safari-webdriver",
-                    "safari-bidi",
-                    "performance-resource-timing",
-                    "session-policy",
-                    "webmcp-page-api"
-                  ],
-                  "type": "string"
-                },
-                "maxItems": 2,
-                "type": "array"
-              },
-              "reason": {
-                "maxLength": 500,
-                "type": "string"
-              },
-              "state": {
-                "enum": [
-                  "supported",
-                  "degraded",
-                  "unsupported"
-                ],
-                "type": "string"
-              }
-            },
-            "required": [
-              "state",
-              "provenance"
-            ],
-            "type": "object"
-          },
-          "javascriptDebugger": {
-            "additionalProperties": false,
-            "properties": {
-              "provenance": {
-                "items": {
-                  "enum": [
-                    "playwright",
-                    "chromium-cdp",
-                    "safari-webdriver",
-                    "safari-bidi",
-                    "performance-resource-timing",
-                    "session-policy",
-                    "webmcp-page-api"
-                  ],
-                  "type": "string"
-                },
-                "maxItems": 2,
-                "type": "array"
-              },
-              "reason": {
-                "maxLength": 500,
-                "type": "string"
-              },
-              "state": {
-                "enum": [
-                  "supported",
-                  "degraded",
-                  "unsupported"
-                ],
-                "type": "string"
-              }
-            },
-            "required": [
-              "state",
-              "provenance"
-            ],
-            "type": "object"
-          },
-          "locators": {
-            "additionalProperties": false,
-            "properties": {
-              "css": {
-                "additionalProperties": false,
-                "properties": {
-                  "provenance": {
-                    "items": {
-                      "enum": [
-                        "playwright",
-                        "chromium-cdp",
-                        "safari-webdriver",
-                        "safari-bidi",
-                        "performance-resource-timing",
-                        "session-policy",
-                        "webmcp-page-api"
-                      ],
-                      "type": "string"
-                    },
-                    "maxItems": 2,
-                    "type": "array"
-                  },
-                  "reason": {
-                    "maxLength": 500,
-                    "type": "string"
-                  },
-                  "state": {
-                    "enum": [
-                      "supported",
-                      "degraded",
-                      "unsupported"
-                    ],
-                    "type": "string"
-                  }
-                },
-                "required": [
-                  "state",
-                  "provenance"
-                ],
-                "type": "object"
-              },
-              "semantic": {
-                "additionalProperties": false,
-                "properties": {
-                  "provenance": {
-                    "items": {
-                      "enum": [
-                        "playwright",
-                        "chromium-cdp",
-                        "safari-webdriver",
-                        "safari-bidi",
-                        "performance-resource-timing",
-                        "session-policy",
-                        "webmcp-page-api"
-                      ],
-                      "type": "string"
-                    },
-                    "maxItems": 2,
-                    "type": "array"
-                  },
-                  "reason": {
-                    "maxLength": 500,
-                    "type": "string"
-                  },
-                  "state": {
-                    "enum": [
-                      "supported",
-                      "degraded",
-                      "unsupported"
-                    ],
-                    "type": "string"
-                  }
-                },
-                "required": [
-                  "state",
-                  "provenance"
-                ],
-                "type": "object"
-              }
-            },
-            "required": [
-              "css",
-              "semantic"
-            ],
-            "type": "object"
-          },
-          "network": {
-            "additionalProperties": false,
-            "properties": {
-              "provenance": {
-                "items": {
-                  "enum": [
-                    "playwright",
-                    "chromium-cdp",
-                    "safari-webdriver",
-                    "safari-bidi",
-                    "performance-resource-timing",
-                    "session-policy",
-                    "webmcp-page-api"
-                  ],
-                  "type": "string"
-                },
-                "maxItems": 2,
-                "type": "array"
-              },
-              "reason": {
-                "maxLength": 500,
-                "type": "string"
-              },
-              "state": {
-                "enum": [
-                  "supported",
-                  "degraded",
-                  "unsupported"
-                ],
-                "type": "string"
-              }
-            },
-            "required": [
-              "state",
-              "provenance"
-            ],
-            "type": "object"
-          },
-          "pageRuntimeEnrichment": {
-            "additionalProperties": false,
-            "properties": {
-              "provenance": {
-                "items": {
-                  "enum": [
-                    "playwright",
-                    "chromium-cdp",
-                    "safari-webdriver",
-                    "safari-bidi",
-                    "performance-resource-timing",
-                    "session-policy",
-                    "webmcp-page-api"
-                  ],
-                  "type": "string"
-                },
-                "maxItems": 2,
-                "type": "array"
-              },
-              "reason": {
-                "maxLength": 500,
-                "type": "string"
-              },
-              "state": {
-                "enum": [
-                  "supported",
-                  "degraded",
-                  "unsupported"
-                ],
-                "type": "string"
-              }
-            },
-            "required": [
-              "state",
-              "provenance"
-            ],
-            "type": "object"
-          },
-          "schemaVersion": {
-            "const": 2,
-            "type": "number"
-          },
-          "screenshots": {
-            "additionalProperties": false,
-            "properties": {
-              "provenance": {
-                "items": {
-                  "enum": [
-                    "playwright",
-                    "chromium-cdp",
-                    "safari-webdriver",
-                    "safari-bidi",
-                    "performance-resource-timing",
-                    "session-policy",
-                    "webmcp-page-api"
-                  ],
-                  "type": "string"
-                },
-                "maxItems": 2,
-                "type": "array"
-              },
-              "reason": {
-                "maxLength": 500,
-                "type": "string"
-              },
-              "state": {
-                "enum": [
-                  "supported",
-                  "degraded",
-                  "unsupported"
-                ],
-                "type": "string"
-              }
-            },
-            "required": [
-              "state",
-              "provenance"
-            ],
-            "type": "object"
-          },
-          "tlsBypass": {
-            "additionalProperties": false,
-            "properties": {
-              "provenance": {
-                "items": {
-                  "enum": [
-                    "playwright",
-                    "chromium-cdp",
-                    "safari-webdriver",
-                    "safari-bidi",
-                    "performance-resource-timing",
-                    "session-policy",
-                    "webmcp-page-api"
-                  ],
-                  "type": "string"
-                },
-                "maxItems": 2,
-                "type": "array"
-              },
-              "reason": {
-                "maxLength": 500,
-                "type": "string"
-              },
-              "state": {
-                "enum": [
-                  "supported",
-                  "degraded",
-                  "unsupported"
-                ],
-                "type": "string"
-              }
-            },
-            "required": [
-              "state",
-              "provenance"
-            ],
-            "type": "object"
-          },
-          "transport": {
-            "enum": [
-              "chromium-launch",
-              "chromium-cdp-attach",
-              "safari-webdriver"
-            ],
-            "type": "string"
-          },
-          "viewportMatrix": {
-            "additionalProperties": false,
-            "properties": {
-              "provenance": {
-                "items": {
-                  "enum": [
-                    "playwright",
-                    "chromium-cdp",
-                    "safari-webdriver",
-                    "safari-bidi",
-                    "performance-resource-timing",
-                    "session-policy",
-                    "webmcp-page-api"
-                  ],
-                  "type": "string"
-                },
-                "maxItems": 2,
-                "type": "array"
-              },
-              "reason": {
-                "maxLength": 500,
-                "type": "string"
-              },
-              "state": {
-                "enum": [
-                  "supported",
-                  "degraded",
-                  "unsupported"
-                ],
-                "type": "string"
-              }
-            },
-            "required": [
-              "state",
-              "provenance"
-            ],
-            "type": "object"
-          },
-          "webmcp": {
-            "additionalProperties": false,
-            "properties": {
-              "provenance": {
-                "items": {
-                  "enum": [
-                    "playwright",
-                    "chromium-cdp",
-                    "safari-webdriver",
-                    "safari-bidi",
-                    "performance-resource-timing",
-                    "session-policy",
-                    "webmcp-page-api"
-                  ],
-                  "type": "string"
-                },
-                "maxItems": 2,
-                "type": "array"
-              },
-              "reason": {
-                "maxLength": 500,
-                "type": "string"
-              },
-              "state": {
-                "enum": [
-                  "supported",
-                  "degraded",
-                  "unsupported"
-                ],
-                "type": "string"
-              }
-            },
-            "required": [
-              "state",
-              "provenance"
-            ],
-            "type": "object"
-          }
-        },
-        "required": [
-          "schemaVersion",
-          "browser",
-          "transport",
-          "actions",
-          "locators",
-          "dom",
-          "console",
-          "network",
-          "screenshots",
-          "javascriptDebugger",
-          "evaluation",
-          "accessibility",
-          "pageRuntimeEnrichment",
-          "viewportMatrix",
-          "tlsBypass",
-          "authSeeding",
-          "webmcp"
-        ],
-        "type": "object"
-      },
-      {
-        "type": "null"
-      }
-    ]
-  },
-  "schemaVersion": {
-    "const": 3,
-    "type": "number"
-  },
-  "status": {
-    "enum": [
-      "starting",
-      "ready",
-      "paused",
-      "failed",
-      "closed"
-    ],
-    "type": "string"
-  },
-  "target": {
-    "anyOf": [
-      {
-        "additionalProperties": false,
-        "properties": {
-          "browser": {
-            "enum": [
-              "chromium",
-              "safari"
-            ],
-            "type": "string"
-          },
-          "isolated": {
-            "type": "boolean"
-          },
-          "isolation": {
-            "additionalProperties": false,
-            "properties": {
-              "browserProcess": {
-                "type": "boolean"
-              },
-              "cache": {
-                "type": "boolean"
-              },
-              "context": {
-                "type": "boolean"
-              },
-              "navigation": {
-                "type": "boolean"
-              },
-              "profile": {
-                "type": "boolean"
-              },
-              "serverState": {
-                "type": "boolean"
-              },
-              "serviceWorkers": {
-                "type": "boolean"
-              },
-              "storage": {
-                "type": "boolean"
-              }
-            },
-            "required": [
-              "browserProcess",
-              "context",
-              "profile",
-              "storage",
-              "cache",
-              "serviceWorkers",
-              "navigation",
-              "serverState"
-            ],
-            "type": "object"
-          },
-          "mode": {
-            "enum": [
-              "launch",
-              "attach",
-              "webdriver"
-            ],
-            "type": "string"
-          },
-          "remote": {
-            "type": "boolean"
-          },
-          "schemaVersion": {
-            "const": 1,
-            "type": "number"
-          },
-          "targetId": {
-            "maxLength": 200,
-            "type": "string"
-          },
-          "title": {
-            "maxLength": 300,
-            "type": "string"
-          },
-          "url": {
-            "maxLength": 2560,
-            "type": "string"
-          },
-          "viewport": {
-            "anyOf": [
-              {
-                "additionalProperties": false,
-                "properties": {
-                  "height": {
-                    "maximum": 9007199254740991,
-                    "minimum": -9007199254740991,
-                    "type": "integer"
-                  },
-                  "width": {
-                    "maximum": 9007199254740991,
-                    "minimum": -9007199254740991,
-                    "type": "integer"
-                  }
-                },
-                "required": [
-                  "width",
-                  "height"
-                ],
-                "type": "object"
-              },
-              {
-                "type": "null"
-              }
-            ]
-          }
-        },
-        "required": [
-          "schemaVersion",
-          "browser",
-          "remote",
-          "url",
-          "title",
-          "viewport",
-          "isolated"
-        ],
-        "type": "object"
-      },
-      {
-        "type": "null"
-      }
-    ]
-  },
-  "tls": {
-    "enum": [
-      "strict",
-      "allow-insecure-loopback"
-    ],
-    "type": "string"
-  },
-  "url": {
-    "maxLength": 2560,
-    "type": "string"
-  },
-  "warnings": {
-    "items": {
-      "maxLength": 500,
-      "type": "string"
-    },
-    "maxItems": 100,
-    "type": "array"
-  }
-}

removedOutput schema / properties / data / required

Removed value: -[
-  "schemaVersion",
-  "id",
-  "projectRoot",
-  "url",
-  "status",
-  "createdAt",
-  "artifactDir",
-  "target",
-  "projectCapabilities",
-  "runtimeCapabilities",
-  "warnings"
-]

removedOutput schema / properties / data / type
```
Removed value: -"object"
```

Changed7 schema fields changedv0.7.0Sep 1, 2026

removedOutput schema / definitions / __schema1

Removed value: -{
-  "anyOf": [
-    {
-      "type": "string"
-    },
-    {
-      "type": "number"
-    },
-    {
-      "type": "boolean"
-    },
-    {
-      "type": "null"
-    },
-    {
-      "items": {
-        "$ref": "#/definitions/__schema1"
-      },
-      "type": "array"
-    },
-    {
-      "additionalProperties": {
-        "$ref": "#/definitions/__schema1"
-      },
-      "propertyNames": {
-        "type": "string"
-      },
-      "type": "object"
-    }
-  ]
-}

addedOutput schema / properties / data / additionalProperties
```
Added value: +false
```

removedOutput schema / properties / data / allOf

Removed value: -[
-  {
-    "$ref": "#/definitions/__schema0"
-  }
-]

addedOutput schema / properties / data / properties

Added value: +{
+  "artifactDir": {
+    "maxLength": 4096,
+    "type": "string"
+  },
+  "artifactState": {
+    "enum": [
+      "retained",
+      "deleted"
+    ],
+    "type": "string"
+  },
+  "authFixture": {
+    "enum": [
+      "seeded-disposable",
+      "none"
+    ],
+    "type": "string"
+  },
+  "createdAt": {
+    "maxLength": 100,
+    "type": "string"
+  },
+  "id": {
+    "format": "uuid",
+    "pattern": "^([0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[1-8][0-9a-fA-F]{3}-[89abAB][0-9a-fA-F]{3}-[0-9a-fA-F]{12}|00000000-0000-0000-0000-000000000000|ffffffff-ffff-ffff-ffff-ffffffffffff)$",
+    "type": "string"
+  },
+  "projectCapabilities": {
+    "additionalProperties": false,
+    "properties": {
+      "angular": {
+        "type": "boolean"
+      },
+      "browserTarget": {
+        "type": "boolean"
+      },
+      "next": {
+        "type": "boolean"
+      },
+      "react": {
+        "type": "boolean"
+      },
+      "serverRuntime": {
+        "type": "boolean"
+      },
+      "vite": {
+        "type": "boolean"
+      },
+      "vue": {
+        "type": "boolean"
+      }
+    },
+    "required": [
+      "browserTarget",
+      "react",
+      "angular",
+      "vue",
+      "vite",
+      "next",
+      "serverRuntime"
+    ],
+    "type": "object"
+  },
+  "projectRoot": {
+    "maxLength": 4096,
+    "type": "string"
+  },
+  "runtimeCapabilities": {
+    "anyOf": [
+      {
+        "additionalProperties": false,
+        "properties": {
+          "accessibility": {
+            "additionalProperties": false,
+            "properties": {
+              "provenance": {
+                "items": {
+                  "enum": [
+                    "playwright",
+                    "chromium-cdp",
+                    "safari-webdriver",
+                    "safari-bidi",
+                    "performance-resource-timing",
+                    "session-policy",
+                    "webmcp-page-api"
+                  ],
+                  "type": "string"
+                },
+                "maxItems": 2,
+                "type": "array"
+              },
+              "reason": {
+                "maxLength": 500,
+                "type": "string"
+              },
+              "state": {
+                "enum": [
+                  "supported",
+                  "degraded",
+                  "unsupported"
+                ],
+                "type": "string"
+              }
+            },
+            "required": [
+              "state",
+              "provenance"
+            ],
+            "type": "object"
+          },
+          "actions": {
+            "additionalProperties": false,
+            "properties": {
+              "provenance": {
+                "items": {
+                  "enum": [
+                    "playwright",
+                    "chromium-cdp",
+                    "safari-webdriver",
+                    "safari-bidi",
+                    "performance-resource-timing",
+                    "session-policy",
+                    "webmcp-page-api"
+                  ],
+                  "type": "string"
+                },
+                "maxItems": 2,
+                "type": "array"
+              },
+              "reason": {
+                "maxLength": 500,
+                "type": "string"
+              },
+              "state": {
+                "enum": [
+                  "supported",
+                  "degraded",
+                  "unsupported"
+                ],
+                "type": "string"
+              }
+            },
+            "required": [
+              "state",
+              "provenance"
+            ],
+            "type": "object"
+          },
+          "authSeeding": {
+            "additionalProperties": false,
+            "properties": {
+              "provenance": {
+                "items": {
+                  "enum": [
+                    "playwright",
+                    "chromium-cdp",
+                    "safari-webdriver",
+                    "safari-bidi",
+                    "performance-resource-timing",
+                    "session-policy",
+                    "webmcp-page-api"
+                  ],
+                  "type": "string"
+                },
+                "maxItems": 2,
+                "type": "array"
+              },
+              "reason": {
+                "maxLength": 500,
+                "type": "string"
+              },
+              "state": {
+                "enum": [
+                  "supported",
+                  "degraded",
+                  "unsupported"
+                ],
+                "type": "string"
+              }
+            },
+            "required": [
+              "state",
+              "provenance"
+            ],
+            "type": "object"
+          },
+          "browser": {
+            "enum": [
+              "chromium",
+              "safari"
+            ],
+            "type": "string"
+          },
+          "console": {
+            "additionalProperties": false,
+            "properties": {
+              "provenance": {
+                "items": {
+                  "enum": [
+                    "playwright",
+                    "chromium-cdp",
+                    "safari-webdriver",
+                    "safari-bidi",
+                    "performance-resource-timing",
+                    "session-policy",
+                    "webmcp-page-api"
+                  ],
+                  "type": "string"
+                },
+                "maxItems": 2,
+                "type": "array"
+              },
+              "reason": {
+                "maxLength": 500,
+                "type": "string"
+              },
+              "state": {
+                "enum": [
+                  "supported",
+                  "degraded",
+                  "unsupported"
+                ],
+                "type": "string"
+              }
+            },
+            "required": [
+              "state",
+              "provenance"
+            ],
+            "type": "object"
+          },
+          "dom": {
+            "additionalProperties": false,
+            "properties": {
+              "provenance": {
+                "items": {
+                  "enum": [
+                    "playwright",
+                    "chromium-cdp",
+                    "safari-webdriver",
+                    "safari-bidi",
+                    "performance-resource-timing",
+                    "session-policy",
+                    "webmcp-page-api"
+                  ],
+                  "type": "string"
+                },
+                "maxItems": 2,
+                "type": "array"
+              },
+              "reason": {
+                "maxLength": 500,
+                "type": "string"
+              },
+              "state": {
+                "enum": [
+                  "supported",
+                  "degraded",
+                  "unsupported"
+                ],
+                "type": "string"
+              }
+            },
+            "required": [
+              "state",
+              "provenance"
+            ],
+            "type": "object"
+          },
+          "evaluation": {
+            "additionalProperties": false,
+            "properties": {
+              "provenance": {
+                "items": {
+                  "enum": [
+                    "playwright",
+                    "chromium-cdp",
+                    "safari-webdriver",
+                    "safari-bidi",
+                    "performance-resource-timing",
+                    "session-policy",
+                    "webmcp-page-api"
+                  ],
+                  "type": "string"
+                },
+                "maxItems": 2,
+                "type": "array"
+              },
+              "reason": {
+                "maxLength": 500,
+                "type": "string"
+              },
+              "state": {
+                "enum": [
+                  "supported",
+                  "degraded",
+                  "unsupported"
+                ],
+                "type": "string"
+              }
+            },
+            "required": [
+              "state",
+              "provenance"
+            ],
+            "type": "object"
+          },
+          "javascriptDebugger": {
+            "additionalProperties": false,
+            "properties": {
+              "provenance": {
+                "items": {
+                  "enum": [
+                    "playwright",
+                    "chromium-cdp",
+                    "safari-webdriver",
+                    "safari-bidi",
+                    "performance-resource-timing",
+                    "session-policy",
+                    "webmcp-page-api"
+                  ],
+                  "type": "string"
+                },
+                "maxItems": 2,
+                "type": "array"
+              },
+              "reason": {
+                "maxLength": 500,
+                "type": "string"
+              },
+              "state": {
+                "enum": [
+                  "supported",
+                  "degraded",
+                  "unsupported"
+                ],
+                "type": "string"
+              }
+            },
+            "required": [
+              "state",
+              "provenance"
+            ],
+            "type": "object"
+          },
+          "locators": {
+            "additionalProperties": false,
+            "properties": {
+              "css": {
+                "additionalProperties": false,
+                "properties": {
+                  "provenance": {
+                    "items": {
+                      "enum": [
+                        "playwright",
+                        "chromium-cdp",
+                        "safari-webdriver",
+                        "safari-bidi",
+                        "performance-resource-timing",
+                        "session-policy",
+                        "webmcp-page-api"
+                      ],
+                      "type": "string"
+                    },
+                    "maxItems": 2,
+                    "type": "array"
+                  },
+                  "reason": {
+                    "maxLength": 500,
+                    "type": "string"
+                  },
+                  "state": {
+                    "enum": [
+                      "supported",
+                      "degraded",
+                      "unsupported"
+                    ],
+                    "type": "string"
+                  }
+                },
+                "required": [
+                  "state",
+                  "provenance"
+                ],
+                "type": "object"
+              },
+              "semantic": {
+                "additionalProperties": false,
+                "properties": {
+                  "provenance": {
+                    "items": {
+                      "enum": [
+                        "playwright",
+                        "chromium-cdp",
+                        "safari-webdriver",
+                        "safari-bidi",
+                        "performance-resource-timing",
+                        "session-policy",
+                        "webmcp-page-api"
+                      ],
+                      "type": "string"
+                    },
+                    "maxItems": 2,
+                    "type": "array"
+                  },
+                  "reason": {
+                    "maxLength": 500,
+                    "type": "string"
+                  },
+                  "state": {
+                    "enum": [
+                      "supported",
+                      "degraded",
+                      "unsupported"
+                    ],
+                    "type": "string"
+                  }
+                },
+                "required": [
+                  "state",
+                  "provenance"
+                ],
+                "type": "object"
+              }
+            },
+            "required": [
+              "css",
+              "semantic"
+            ],
+            "type": "object"
+          },
+          "network": {
+            "additionalProperties": false,
+            "properties": {
+              "provenance": {
+                "items": {
+                  "enum": [
+                    "playwright",
+                    "chromium-cdp",
+                    "safari-webdriver",
+                    "safari-bidi",
+                    "performance-resource-timing",
+                    "session-policy",
+                    "webmcp-page-api"
+                  ],
+                  "type": "string"
+                },
+                "maxItems": 2,
+                "type": "array"
+              },
+              "reason": {
+                "maxLength": 500,
+                "type": "string"
+              },
+              "state": {
+                "enum": [
+                  "supported",
+                  "degraded",
+                  "unsupported"
+                ],
+                "type": "string"
+              }
+            },
+            "required": [
+              "state",
+              "provenance"
+            ],
+            "type": "object"
+          },
+          "pageRuntimeEnrichment": {
+            "additionalProperties": false,
+            "properties": {
+              "provenance": {
+                "items": {
+                  "enum": [
+                    "playwright",
+                    "chromium-cdp",
+                    "safari-webdriver",
+                    "safari-bidi",
+                    "performance-resource-timing",
+                    "session-policy",
+                    "webmcp-page-api"
+                  ],
+                  "type": "string"
+                },
+                "maxItems": 2,
+                "type": "array"
+              },
+              "reason": {
+                "maxLength": 500,
+                "type": "string"
+              },
+              "state": {
+                "enum": [
+                  "supported",
+                  "degraded",
+                  "unsupported"
+                ],
+                "type": "string"
+              }
+            },
+            "required": [
+              "state",
+              "provenance"
+            ],
+            "type": "object"
+          },
+          "schemaVersion": {
+            "const": 2,
+            "type": "number"
+          },
+          "screenshots": {
+            "additionalProperties": false,
+            "properties": {
+              "provenance": {
+                "items": {
+                  "enum": [
+                    "playwright",
+                    "chromium-cdp",
+                    "safari-webdriver",
+                    "safari-bidi",
+                    "performance-resource-timing",
+                    "session-policy",
+                    "webmcp-page-api"
+                  ],
+                  "type": "string"
+                },
+                "maxItems": 2,
+                "type": "array"
+              },
+              "reason": {
+                "maxLength": 500,
+                "type": "string"
+              },
+              "state": {
+                "enum": [
+                  "supported",
+                  "degraded",
+                  "unsupported"
+                ],
+                "type": "string"
+              }
+            },
+            "required": [
+              "state",
+              "provenance"
+            ],
+            "type": "object"
+          },
+          "tlsBypass": {
+            "additionalProperties": false,
+            "properties": {
+              "provenance": {
+                "items": {
+                  "enum": [
+                    "playwright",
+                    "chromium-cdp",
+                    "safari-webdriver",
+                    "safari-bidi",
+                    "performance-resource-timing",
+                    "session-policy",
+                    "webmcp-page-api"
+                  ],
+                  "type": "string"
+                },
+                "maxItems": 2,
+                "type": "array"
+              },
+              "reason": {
+                "maxLength": 500,
+                "type": "string"
+              },
+              "state": {
+                "enum": [
+                  "supported",
+                  "degraded",
+                  "unsupported"
+                ],
+                "type": "string"
+              }
+            },
+            "required": [
+              "state",
+              "provenance"
+            ],
+            "type": "object"
+          },
+          "transport": {
+            "enum": [
+              "chromium-launch",
+              "chromium-cdp-attach",
+              "safari-webdriver"
+            ],
+            "type": "string"
+          },
+          "viewportMatrix": {
+            "additionalProperties": false,
+            "properties": {
+              "provenance": {
+                "items": {
+                  "enum": [
+                    "playwright",
+                    "chromium-cdp",
+                    "safari-webdriver",
+                    "safari-bidi",
+                    "performance-resource-timing",
+                    "session-policy",
+                    "webmcp-page-api"
+                  ],
+                  "type": "string"
+                },
+                "maxItems": 2,
+                "type": "array"
+              },
+              "reason": {
+                "maxLength": 500,
+                "type": "string"
+              },
+              "state": {
+                "enum": [
+                  "supported",
+                  "degraded",
+                  "unsupported"
+                ],
+                "type": "string"
+              }
+            },
+            "required": [
+              "state",
+              "provenance"
+            ],
+            "type": "object"
+          },
+          "webmcp": {
+            "additionalProperties": false,
+            "properties": {
+              "provenance": {
+                "items": {
+                  "enum": [
+                    "playwright",
+                    "chromium-cdp",
+                    "safari-webdriver",
+                    "safari-bidi",
+                    "performance-resource-timing",
+                    "session-policy",
+                    "webmcp-page-api"
+                  ],
+                  "type": "string"
+                },
+                "maxItems": 2,
+                "type": "array"
+              },
+              "reason": {
+                "maxLength": 500,
+                "type": "string"
+              },
+              "state": {
+                "enum": [
+                  "supported",
+                  "degraded",
+                  "unsupported"
+                ],
+                "type": "string"
+              }
+            },
+            "required": [
+              "state",
+              "provenance"
+            ],
+            "type": "object"
+          }
+        },
+        "required": [
+          "schemaVersion",
+          "browser",
+          "transport",
+          "actions",
+          "locators",
+          "dom",
+          "console",
+          "network",
+          "screenshots",
+          "javascriptDebugger",
+          "evaluation",
+          "accessibility",
+          "pageRuntimeEnrichment",
+          "viewportMatrix",
+          "tlsBypass",
+          "authSeeding",
+          "webmcp"
+        ],
+        "type": "object"
+      },
+      {
+        "type": "null"
+      }
+    ]
+  },
+  "schemaVersion": {
+    "const": 3,
+    "type": "number"
+  },
+  "status": {
+    "enum": [
+      "starting",
+      "ready",
+      "paused",
+      "failed",
+      "closed"
+    ],
+    "type": "string"
+  },
+  "target": {
+    "anyOf": [
+      {
+        "additionalProperties": false,
+        "properties": {
+          "browser": {
+            "enum": [
+              "chromium",
+              "safari"
+            ],
+            "type": "string"
+          },
+          "isolated": {
+            "type": "boolean"
+          },
+          "isolation": {
+            "additionalProperties": false,
+            "properties": {
+              "browserProcess": {
+                "type": "boolean"
+              },
+              "cache": {
+                "type": "boolean"
+              },
+              "context": {
+                "type": "boolean"
+              },
+              "navigation": {
+                "type": "boolean"
+              },
+              "profile": {
+                "type": "boolean"
+              },
+              "serverState": {
+                "type": "boolean"
+              },
+              "serviceWorkers": {
+                "type": "boolean"
+              },
+              "storage": {
+                "type": "boolean"
+              }
+            },
+            "required": [
+              "browserProcess",
+              "context",
+              "profile",
+              "storage",
+              "cache",
+              "serviceWorkers",
+              "navigation",
+              "serverState"
+            ],
+            "type": "object"
+          },
+          "mode": {
+            "enum": [
+              "launch",
+              "attach",
+              "webdriver"
+            ],
+            "type": "string"
+          },
+          "remote": {
+            "type": "boolean"
+          },
+          "schemaVersion": {
+            "const": 1,
+            "type": "number"
+          },
+          "targetId": {
+            "maxLength": 200,
+            "type": "string"
+          },
+          "title": {
+            "maxLength": 300,
+            "type": "string"
+          },
+          "url": {
+            "maxLength": 2560,
+            "type": "string"
+          },
+          "viewport": {
+            "anyOf": [
+              {
+                "additionalProperties": false,
+                "properties": {
+                  "height": {
+                    "maximum": 9007199254740991,
+                    "minimum": -9007199254740991,
+                    "type": "integer"
+                  },
+                  "width": {
+                    "maximum": 9007199254740991,
+                    "minimum": -9007199254740991,
+                    "type": "integer"
+                  }
+                },
+                "required": [
+                  "width",
+                  "height"
+                ],
+                "type": "object"
+              },
+              {
+                "type": "null"
+              }
+            ]
+          }
+        },
+        "required": [
+          "schemaVersion",
+          "browser",
+          "remote",
+          "url",
+          "title",
+          "viewport",
+          "isolated"
+        ],
+        "type": "object"
+      },
+      {
+        "type": "null"
+      }
+    ]
+  },
+  "tls": {
+    "enum": [
+      "strict",
+      "allow-insecure-loopback"
+    ],
+    "type": "string"
+  },
+  "url": {
+    "maxLength": 2560,
+    "type": "string"
+  },
+  "warnings": {
+    "items": {
+      "maxLength": 500,
+      "type": "string"
+    },
+    "maxItems": 100,
+    "type": "array"
+  }
+}

addedOutput schema / properties / data / required

Added value: +[
+  "schemaVersion",
+  "id",
+  "projectRoot",
+  "url",
+  "status",
+  "createdAt",
+  "artifactDir",
+  "target",
+  "projectCapabilities",
+  "runtimeCapabilities",
+  "warnings"
+]

addedOutput schema / properties / data / type
```
Added value: +"object"
```

changedOutput schema / properties / error / properties / details / allOf

Previous value: -[
-  {
-    "$ref": "#/definitions/__schema1"
-  }
-]New value: +[
+  {
+    "$ref": "#/definitions/__schema0"
+  }
+]

First observedv0.5.0-next.0Aug 30, 2026

TDQS

A3.8/5.0

Behavior4/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare destructiveHint=true and idempotentHint=true. The description adds value beyond those flags by specifying that browser resources owned by the session are released, clarifying what gets affected. It does not contradict the annotations.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

One sentence, front-loaded action, no filler, and no repetition of schema details. Every word contributes to the meaning.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness3/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

The tool has an output schema and useful annotations, so return values and safety profile are covered. However, the artifactPolicy parameter is central to the close operation's side effects, and its semantics are completely unexplained, leaving an agent uncertain about artifact deletion.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters2/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 0%, so the description needed to compensate, but it only refers vaguely to the 'selected session' and never explains artifactPolicy. The meaning of retain vs delete and their side effects on artifacts is absent, leaving a destructive parameter under-documented.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description uses a specific verb ('Close') and names the resource ('session') plus a concrete consequence ('release any browser resources owned by it'). This clearly distinguishes it from sibling tools like web_session_start and web_session_status, making the call intent unambiguous.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines3/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The usage is implied: an agent should call this when it wants to close a selected debug session. However, the description provides no explicit guidance on when to choose this over alternatives, such as checking status first or using web_debug_control for finer-grained control, and it names no exclusions.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

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