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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so the safety profile is fully covered. The description adds one genuinely new behavioral fact, that it returns 'last-known-good' data, implying possible staleness or fallback when the current read fails. It says nothing about what happens on a device with no display set, which is the main behavioral ambiguity left.

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?

A single front-loaded sentence with no filler; the distinguishing constraint (no rendered HTML) is placed where it will be read. Nothing could be removed without losing 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?

An output schema exists, so return fields need not be enumerated, and the description correctly focuses on scope and payload shape instead. The remaining gap is the unexplained required 'device' parameter and the no-display fallback case, which is modest for a single-parameter read tool.

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 a single required 'device' parameter with 0% schema description coverage, and the description never mentions it, so neither the schema nor the text explains whether it is a device ID, name, or where to obtain it. With one undocumented parameter the description needed to compensate and does not.

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 (returns) and resource (current and last-known-good view metadata) and scopes it by excluding rendered HTML, which differentiates it from the render/broadcast siblings. It stops short of naming those siblings explicitly, so the differentiation is inferential rather than stated.

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 implied rather than stated: the agent can infer this is the call for display state when the HTML payload is not wanted, and the mention of 'without the rendered HTML' hints that display_render_html is the alternative. There is no explicit when-to-use or when-not-to-use guidance, and no mention of prerequisites such as an active display.

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