Browser Network Block

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It mentions that blocking applies 'across all sessions' and uses URL globs, which is useful. However, it does not disclose whether the blocking is immediate, whether it requires a page reload to take effect, whether it is reversible, or any side effects (e.g., breaking pages that depend on blocked resources). Given the lack of annotations, this is a significant gap.

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

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

The description is succinct: two sentences and an example list. The core purpose is front-loaded in the first sentence, and the examples are immediately actionable. There is no fluff or repetition. Every word earns its place.

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

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

For a simple tool with one parameter and an output schema, the description covers the essential aspects: what it does, how to specify the globs, and a typical use case. It does not mention reversibility (unblocking) or potential side effects, but given the tool's simplicity and the presence of an output schema, this is a minor gap. Overall, it is adequately complete for an agent to call it correctly.

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

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

The schema has only one parameter, url_globs, with no description in the schema itself (0% coverage). The description compensates by explaining the glob format and providing concrete examples (e.g., ['**/*.css', '**/ads.js']). This gives the agent clear guidance on what values to provide, well beyond the raw schema.

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

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

The description states a specific verb and resource: 'Block requests matching URL globs across all sessions.' It clearly identifies the action (blocking), the target (requests), and the scope (all sessions). It also gives concrete examples of glob patterns and the intended use case (blocking ads/trackers to speed up automation). This makes the tool's purpose unambiguous and distinguishes it from siblings like browser_network_unblock.

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

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

The description implies usage ('Blocks ads and trackers to speed up automation dramatically') but does not explicitly state when to use this tool versus alternatives such as browser_network_unblock or browser_network_capture_start. There is no mention of when not to use it or how it interacts with other network-related tools. The guidance is implicit rather than explicit, so a middle score is appropriate.

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