break_on_xhr

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

Annotations indicate mutation (readOnlyHint=false) and non-destructive (destructiveHint=false). Description adds that the breakpoint is for future requests only, does not inspect past traffic, and requires subsequent steps. Also explains how the URL pattern ties to list_breakpoints and remove_breakpoint.

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?

Description is a single paragraph of about 100 words, front-loaded with purpose, then usage sequence, then relation to other tools. Every sentence contributes. Could be slightly more compact, but efficient overall.

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 existence of an output schema, return values are not needed in description. Covers what, when, how, and parameter details. Could explicitly mention that the breakpoint causes a pause on request, but context is fairly complete.

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 has one parameter 'url' with description. Tool description adds context: case-sensitive, should be a narrow endpoint path from list_network_requests, retain exact string for removal. This goes beyond the schema description. With 100% schema coverage, baseline is 3, but added value justifies 4.

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 purpose: setting a URL-substring breakpoint for future XHR/Fetch to inspect runtime arguments, variables, or payloads. It distinguishes from get_request_initiator, which handles already captured requests.

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?

Provides explicit guidance: use when need to inspect request details at runtime, avoid for already captured requests (use get_request_initiator instead). Specifies the workflow: set before reproducing action, then call get_paused_info/evaluate_script, then step/resume. Also notes it does not inspect past traffic.

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