Skip to main content
Glama
Sign In
SuperDev

SuperDev

by Xsxdot
OverviewSchemaSourceRelated ServersDiscussionsAdmin
Go
Local

Browser evaluate

browser_evaluate

Evaluates a JavaScript expression within a specified browser debug session and returns the serializable result.

Instructions

Evaluate JavaScript in a browser debug session page and return the serializable result.

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "session_id": "<session_id>",
      "expression": "<expression>"
    },
    "name": "browser_evaluate"
  }
}

Input Schema

NameRequiredDescriptionDefault
expressionYes
session_idYes

Schema Changelog

Changes observed during successful MCP inspections.

  1. First observedv0.1.0

TDQS

C2.9/5.0
Behavior2/5

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

With no annotations provided, the description bears the full burden of behavioral disclosure. It mentions 'serializable result' but omits important behaviors such as side effects of JavaScript execution, whether the page state may be mutated, or any permission or session requirements. This is a significant gap for a tool that executes arbitrary code.

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 a single, front-loaded sentence with no redundant words. It efficiently communicates the core action and result type.

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

Completeness2/5

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

Given the tool executes arbitrary JavaScript and has no output schema or annotations, the description is too sparse. It fails to mention prerequisites (active debug session), side effects, serialization limitations, or what happens when results are not serializable. This leaves the agent underinformed for safe and correct invocation.

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

Parameters1/5

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

Schema description coverage is 0%, and the description fails to explain either parameter. 'expression' is only implicitly JavaScript, and 'session_id' is not described at all. The description adds no meaning beyond the bare schema field names.

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 clearly states the action (evaluate JavaScript) and the target resource (browser debug session page), and specifies the outcome (return the serializable result). This distinguishes it from generic debug_evaluate or browser snapshot tools by emphasizing the browser debug session context.

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

Usage Guidelines2/5

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

The description gives no guidance on when to use this tool versus alternatives. There is no mention of exclusions, prerequisites, or comparisons to sibling tools like debug_evaluate or browser_console_logs. The context is implied but not explicit.

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

Deploy Server

Other Tools