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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so the safety profile is covered. The description adds useful behavioral detail beyond that: it names the reported counters (paused/mocked/aborted/passedThrough/errors) and warns that a non-matching route yields mocked: 0, which is a real diagnostic gotcha.

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?

Two tight sentences with no filler. The core purpose and the full list of reported fields are front-loaded, and the diagnostic caveat follows only after the essential content.

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?

With no output schema, the description carries the burden of describing return content, and it does: interception armed state, attached page target, active routes, and named counter buckets. An agent has enough to call it and to interpret the result without further documentation.

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?

There is only one parameter (udid) and schema description coverage is 100%, so the schema fully documents it. The description adds no extra meaning about the parameter, which is the expected baseline when the schema already does the work.

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 opens with a specific verb and resource ('Report whether browser interception is currently armed on this device') and then enumerates exactly what is reported: page target, active routes, and per-outcome hit counters. This clearly separates it from the sibling mock_list/mock_add/mock_remove tools, which manage rather than report state.

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?

Usage is only implied. 'Check the counters to confirm a mock is actually firing' tells the agent how to interpret output, but there is no explicit statement of when to call this versus webpage_mock_list or webpage_mock_add, and no prerequisites or exclusions are given.

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