tv_playback_status

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

Annotations already establish readOnly, non-destructive, closed-world behavior, so the description's added value is the data-quality disclosure: results are app-reported, may omit titles, and sessions may be absent or stale. That is exactly the kind of caveat an agent needs before trusting the output, though it does not cover freshness timing or what an absent session looks like structurally.

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 compact sentence, front-loaded with the verb and resource, with two qualifying clauses that each carry real information. Nothing is redundant with the title or schema, and no filler is present.

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 parameters and an output schema available, the description does not need to explain return values, and it covers scope plus the absent/stale caveat. The only shortfall is the absence of routing guidance relative to the nearby tv_playback and tv_status tools.

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?

The tool takes zero parameters, so there is nothing for the description to disambiguate and the baseline of 4 applies. The description correctly spends its words on scope and result reliability instead of inventing parameter detail.

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?

"Read app-reported playback states" gives a specific verb plus a tightly scoped resource, and "excluding titles" narrows what data is returned. It is clear on its own, but with siblings named tv_playback and tv_status present, it never states which of those it is not, leaving the agent to infer the boundary.

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: an agent can infer it should call this when it needs current playback state. The caveat "sessions can be absent or stale" is a useful warning about results, but there is no explicit when-to-use versus tv_playback or tv_status, and no stated prerequisite for having connected to the TV first.

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