fail_requests

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

No annotations are provided, so the description carries the full burden. It explains that the tool fails every request matching a pattern with a specified error reason, and lists valid error values. However, it does not disclose the scope (e.g., persistent or per-session), how to revert the interception, or any side effects.

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 concise—two sentences that front-load the purpose and then detail the error_reason constraint. Every sentence adds necessary information, and there is no redundancy.

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?

Given the tool's 2 parameters and presence of an output schema, the description covers the core behavior but lacks information on operation scope (e.g., does it affect all tabs or current session?), how to stop the interception, and what the return value signifies. These gaps reduce completeness.

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?

With schema_description_coverage at 0%, the description adds significant meaning. It explains url_pattern as a pattern for matching requests and enumerates valid error_reason values (a CDP list). This goes beyond the bare schema, though it could be more precise about the pattern matching format (e.g., regex or substring).

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's action: 'Fail every request matching url_pattern with error_reason.' This distinguishes it from sibling tools like mock_response (which mocks responses) and block_urls (which blocks URLs), as it specifically introduces failure with an error reason.

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 for failing network requests but does not provide explicit guidance on when to use this tool versus alternatives like block_urls or mock_response. It mentions the constraint that error_reason must be a valid CDP value but omits context on prerequisites or post-conditions.

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