web-debug-mcp

Overview Schema Related Servers Score Discussions

Start web debug session

web_session_start

Destructive

Start or attach to a specific local Chromium or Safari page for debugging using an explicit URL and CDP, WebDriver, or executable settings. Optionally pin the exact page with a target ID.

Instructions

Start or attach to an explicitly selected local Chromium or Safari page using an explicit URL and CDP, WebDriver, or executable settings. Chromium can opt into one guarded HTTPS loopback origin and a project-contained disposable auth fixture; attached Chromium can supply targetId to pin the exact page. Safari remains strict and CSS-only.

Input Schema

TableJSON Schema

Name	Required	Default
`tls`	No	strict
`url`	Yes
`browser`	No	chromium
`headless`	No
`targetId`	No
`viewport`	No
`allowRemote`	No
`authFixture`	No
`cdpEndpoint`	No
`projectRoot`	No	/app
`executablePath`	No
`webdriverEndpoint`	No

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. Dates show when Glama detected each change.

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

A4.4/5.0

Behavior4/5

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

Annotations already mark the operation as non-read-only, non-idempotent, and destructive, and the description adds useful behavioral nuance: optional guarded loopback TLS, a disposable auth fixture, targetId pinning for attached Chromium, and the stricter Safari/CSS-only path. These details shape agent expectations without contradicting 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?

The description is two dense sentences with no filler and starts with the action. Every clause adds a distinct constraint or mode, so it remains tightly packed despite the technical jargon.

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

Completeness4/5

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

For a 12-parameter tool with no schema-level descriptions, the description covers the core choices, browser differences, and attach behavior, while the output schema covers return details. It leaves some parameters (e.g., allowRemote, viewport) mostly to inference, but the remaining information is largely recoverable from names, defaults, and enums. This is adequate but not exhaustively complete.

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

Parameters4/5

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

Schema description coverage is 0%, so the prose carries the semantic load. It meaningfully explains key parameters: CDP/WebDriver/executable settings, targetId for precise attachment, tls via guarded loopback, and authFixture/projectRoot through the disposable fixture. A few parameters like headless, viewport, and allowRemote rely on name/type inference, but the most decision-critical ones are covered.

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 names a concrete action ('Start or attach'), a specific resource ('local Chromium or Safari page'), and the invocation route ('explicit URL and CDP, WebDriver, or executable settings'). This goes beyond the title and clearly distinguishes the tool from session-status, capture, and close siblings.

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

Usage Guidelines4/5

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

The opening phrase makes the intended context clear: use this when a browser debugging session needs to be started or attached to a specific page. It does not explicitly name sibling tools or provide when-not-to-use guidance, but the transport-mode options and targetId attach behavior give enough contextual direction.

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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