block_urls

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

With no annotations, the description must disclose behavioral traits. It doesn't mention whether blocking is reversible, whether it affects all contexts or just the current one, what happens to blocked navigations (error, silent?), or any statefulness. It only states the action without context.

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?

Single sentence, front-loaded with verb and object. Efficient but perhaps too sparse; still it's well-structured for what it says.

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?

No output schema, no annotations, and the description is minimal. For a tool that modifies browser/navigation behavior, it's very incomplete. It doesn't explain persistence, scope, or interaction with other navigation tools.

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?

Schema coverage is 0%, so the description must compensate. It mentions 'glob-style URL patterns' but gives no details on pattern syntax, examples, or constraints. It doesn't add much beyond the schema's array-of-strings.

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 clearly states the tool blocks navigations based on glob-style URL patterns, using a specific verb ('block') and resource ('navigations'). It distinguishes from siblings like stop_network_capture and navigate by focusing on blocking rather than navigating or capturing.

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?

No guidance on when to use this tool versus alternatives, no conditions or exclusions. It simply states what it does without context.

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