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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed-world), and the description adds genuinely new behavioral context: the web-content-only interception scope, that nothing device-wide changes, and that no certificate is installed. That scope/certificate clarification is exactly the kind of context annotations cannot convey.

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?

Front-loads the core action before the scoping caveats, which is correct ordering. It is slightly verbose in the emphatic negation ('are NOT intercepted and never will be by this tool'), but the extra clauses earn their place by preventing a common misinterpretation.

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 read-only list tool with no output schema, the description conveys what is returned (registered routes in match order). It does not describe the shape/fields of each returned route, but otherwise an agent has everything needed 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?

Schema coverage is 100% for the single 'udid' parameter, so the schema already documents it fully. The description only alludes to the device via 'for this device' and adds no syntax or format detail beyond the schema, making the baseline 3 appropriate.

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?

States a specific verb (List) and resource (Safari/WKWebView mock/abort routes registered for this device) plus the ordering semantics ('match order, first match wins'). An agent can immediately distinguish this read operation from the sibling mock_add/mock_remove/mock_clear/mock_status tools.

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?

Clearly scopes when the tool is relevant ('WEB CONTENT ONLY', intercepts browser/WebView page requests) and gives an explicit exclusion (native app code is NOT intercepted). It stops short of naming alternative tools or stating a when-to-inspect workflow (e.g., after mock_add), so it is clear context without full alternative routing.

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