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browser_network_capture_start

Start capturing browser network traffic through Chrome DevTools Protocol for a session, with optional URL filtering and headers or post data collection.

Instructions

Start CDP-level network capture.

Input Schema

TableJSON Schema
NameRequiredDescriptionDefault
url_regexNo
session_idYes
max_entriesNo
include_headersNo
include_post_dataNo

Output Schema

TableJSON Schema
NameRequiredDescriptionDefault

No arguments

Schema Changelog

Changes observed during successful MCP inspections.

  1. First observedv0.5.1

TDQS

C2.4/5.0
Behavior2/5

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

With no annotations, the description carries the full behavioral burden and discloses almost nothing. It does not mention that capture is bounded by max_entries (default 2000), whether starting a capture overwrites a prior one, whether capture continues until explicitly stopped, or any memory/performance implications of protocol-level recording.

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

Conciseness2/5

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

A single fragmentary sentence with no waste, but at this length it is under-specified rather than concise — the brevity comes at the cost of any usable detail for a five-parameter tool. Front-loading is fine; substance is missing.

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?

An output schema exists so return values need not be described, but for a capture-start tool with five undocumented parameters, no annotations, and a four-tool capture family, the description omits everything an agent needs: prerequisites, filtering behavior, and the stop/read lifecycle.

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 mentions none of the five parameters. The meaning of url_regex (what syntax, does null mean capture-all), max_entries, include_headers, and include_post_data is left entirely undocumented in both schema and prose.

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

Purpose4/5

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

States a specific verb ('Start') and resource ('CDP-level network capture'), and the 'CDP-level' qualifier hints at a lower-level capture than sibling browser_network_requests. However, it never explicitly contrasts itself with the closely-named siblings browser_network_capture_stop, browser_network_capture_get, or browser_network_capture_status.

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?

No when-to-use guidance at all: it does not say whether an active session is required, whether capture must be paired with browser_network_capture_stop, or how it differs from reading browser_network_requests. The agent must infer the whole lifecycle from sibling names.

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