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

Adds substantial behavior beyond the annotations: the backup is applied at the screen's next check-in (every few hours), the failover swap semantics are spelled out, and the one-backup-per-screen replacement rule is disclosed. The annotations only cover idempotency and non-destructiveness, so this latency and state-transition detail is genuinely new information.

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?

Purpose is front-loaded and every sentence carries distinct behavioral content, but the swap clause restates itself ('if that joins the two swap places: the backup becomes its WiFi and the old WiFi becomes the backup'). Tightening that redundancy would make it fully economical.

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 3-parameter mutation with full schema coverage, annotations, and an output schema, the description covers the remaining gaps an agent would care about: propagation delay, replacement behavior, and what happens on failover. Nothing needed to call this correctly is missing.

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 ssid, password (empty for open networks), and device_id are already documented in the schema. The description adds no parameter-level meaning beyond that, so the baseline of 3 applies.

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 and resource ('Give a screen a backup WiFi network') and implicitly distinguishes itself from the sibling host.screens.clear_wifi by making the object 'backup WiFi' explicit. An agent can tell this apart from clearing WiFi without opening either 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?

Provides clear when-to-use context — 'ahead of a network change, or while it is offline' — which is exactly the scenario an agent needs to recognize. It does not name the alternative sibling (host.screens.clear_wifi) or state when not to use it, so it stops short of full routing guidance.

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