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

With no annotations provided, the description carries the full burden, and it does a strong job: it discloses the update-in-place semantics for matching 'id', the immediate effect, survival across navigation, and the explicit non-goal (native app interception). It also discloses the subtle iOS charset behavior in headers. It falls slightly short of a 5 only because it doesn't specify what the response looks like or address failure modes such as 'what happens if id is missing'.

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 dense but every sentence adds value: scope, modes, defaults, navigation behavior, and an explicit pointer to the sibling tool. It is somewhat long with capitalized emphasis that may be unnecessary, but it remains highly informative and well-organized, leading with the core purpose before caveats.

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 13-parameter tool with no output schema, the description covers the conceptual model, the update semantics, and the critical scope limitation, which is enough for an agent to know when and how to use it. Minor gaps remain—there is no mention of how to verify a route was added or how to remove it—but the sibling list and parameter descriptions already cover removal. Overall it is complete for selection and invocability.

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 description coverage is 100%, so the schema already documents each parameter thoroughly. The tool description adds important semantic context beyond that: it explains 'mock' vs 'abort' behavior, clarifies the default mode, and notes that routes apply immediately and survive navigation. It also clarifies that the tool covers only WebView/browser content, which affects how matchUrl and pageId parameters are interpreted.

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 begins with a specific verb ('Add (or update in place)') and clearly identifies the resource: a mock/abort rule for Safari/WKWebView requests on this device. It distinguishes itself from related tools by explicitly stating the native-scope sibling tool to use instead, and the named modes 'mock' and 'abort' precisely define the behavior.

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 explicitly states when to use this tool versus alternatives, saying 'For requests made by native app code use ios_traffic_mock_add instead.' It also explains the WEB CONTENT ONLY scope, provides default behavior, and clears up that no device-wide changes or certificates are installed. This gives the agent clear selection guidance.

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