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

Beyond the annotations (readOnly=false, destructive=false, openWorld=false, idempotent=false), the description discloses substantial behavioral context: routes are stored per-device, take effect live with no restart, the 'abort' mode kills the connection so the app sees a network failure, and certificate-pinned apps can never be intercepted so such routes silently never match. These are exactly the operational traits an agent needs and cannot derive from the annotations.

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?

It is a single dense paragraph, front-loaded with the core verb and the add-or-update behavior before moving to mode semantics, prerequisites, and limitations. There is mild redundancy with the schema on mode defaults, but for a 12-parameter mutation tool the length is justified and every sentence carries information.

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 12-parameter mutation tool with no output schema, the description supplies the missing context: the prerequisite capture session, per-device live-effect storage, the two mode behaviors, and the pinning limitation. Nothing critical to invoking it correctly is absent; only the exact return payload is unspecified, which is acceptable without an output schema.

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%, so the baseline is 3, but the description adds meaning by explaining the mock-vs-abort mode semantics (status/headers/body only apply to mock), the in-place update behavior when `id` matches, and that routes are per-device. It stops short of detailing matchType or delayMs syntax, which the schema already covers.

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 states a specific verb (add/update in place) and resource (a mock/abort rule for HTTPS traffic in the TLS-inspecting proxy), and clearly distinguishes this from plain capture by explaining that matching requests never reach the real server. An agent can immediately tell this apart from ios_traffic_flows or ios_traffic_start without opening the schema.

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?

It states the prerequisite explicitly ('Requires TLS capture to already be running on this device (ios_traffic_start)') and explains the two operating modes with their effect. It does not, however, name the sibling tools an agent would use to inspect or remove routes (ios_traffic_mock_list / ios_traffic_mock_remove) or give explicit when-not-to-use guidance.

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