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

Adds real context beyond the annotations (destructiveHint/idempotent/readOnly already declare the safety profile): it discloses that existing screen content is displaced, that display persists until a time or manual revert, and that the screen must be online with a paired player. The return value ('what the screen shows afterwards', including online/paired) is described. It does not say what happens to the displaced content or whether the disruption is user-visible to viewers.

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?

Three tightly packed sentences, with the core action and persistence rule front-loaded and prerequisites/return info after. Dense but every sentence carries distinct information; no filler.

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 4-parameter mutation tool with no output schema, the description covers preconditions, persistence, split-screen targeting, and the shape of the response. Remaining gaps are minor: no mention of required permissions/account scope or how a failed push manifests.

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 only 25% (only 'until' is documented), so the description must compensate. It does explain subscreen_id's requirement for split screens and the indefinite behavior when 'until' is omitted, but screen_id and content_id get no added meaning beyond their names — e.g. whether content_id must pre-exist or which content types are valid is unstated.

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 ('show content on one screen, or on one sub-screen of a split screen') with precise scope: it replaces current output and persists until a time or until reverted. This implicitly distinguishes it from the release_* siblings, which restore normal state rather than assign content.

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?

Gives clear conditional guidance: a split-screen target requires subscreen_id, and omitting 'until' means indefinite display. It does not name release_screen or release_all as the way to undo the push, nor state when a different tool (e.g. activate_scene) would be preferred, so it falls short of full when/when-not routing.

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