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debugger_targets

Read-onlyIdempotent

List all CDP-attachable browser targets, including service workers and extension background pages, even when no tabs are open.

Instructions

List every CDP-attachable target, including service workers and extension background pages that list_tabs never shows. Works with no tabs open.

Input Schema

TableJSON Schema
NameRequiredDescriptionDefault
session_idNo

Output Schema

TableJSON Schema
NameRequiredDescriptionDefault

No arguments

Schema Changelog

Changes observed during successful MCP inspections.

  1. First observedv0.1.0

TDQS

A3.9/5.0
Behavior4/5

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

Annotations already declare the tool read-only, idempotent, open-world, and non-destructive. The description adds useful behavioral context about the scope of targets returned and the fact that it works without open tabs, which goes beyond the annotations and helps the agent predict behavior.

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 tight sentences with no filler. The core action and scope are front-loaded, and the contrast with list_tabs earns its place by adding useful differentiation.

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 simple read-only list tool, the description covers the main use case, scope, and an important edge case (no tabs open), while an output schema exists so return values do not need explanation. The only clear gap is the undocumented optional session_id parameter.

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 does not mention the optional session_id parameter at all. Since the description bears the burden of explaining parameters when the schema does not, this is a significant gap.

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 ('List') and a precise resource ('every CDP-attachable target'), and differentiates itself from list_tabs by explicitly naming service workers and extension background pages. This makes the tool's purpose unmistakable and distinguishes it from siblings without opening schemas.

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 description gives clear context: it is the tool to use when you need CDP targets beyond what list_tabs shows, and it works even with no tabs open. It does not explicitly discuss when not to use it or compare it to other siblings like list_all_tabs, but the intended usage is evident.

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