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

With no annotations, the description carries the full disclosure burden, and it provides substantive constraints: media keys are sealed through the feed and never reach the relay, and calls require a media-capable client. This corrects a likely false assumption that the agent could participate directly in calls. It could be stronger by stating what the tool itself returns or that it is strictly read-only.

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?

The roughly 40-word description is dense and front-loaded: the capability list appears first, followed by the two most decision-relevant constraints. There is no filler or repetition of the title, and each of the three sentences contributes a distinct fact.

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 parameterless informational tool without an output schema, the description explains scope, a critical security property, and the agent's role in handoff. It is mostly complete, but it leaves domain terms like 'posture' and 'join flow' undefined and never states what response shape to expect. Still, given the tool's simplicity, the gaps are minor.

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 input schema has zero parameters, giving a baseline of 4; there is nothing for the description to add about parameter meaning. The description instead clarifies what the returned information covers (capabilities, security posture, join flow), which is appropriate for a parameterless info tool.

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 tool's purpose is readable from the title and first sentence: it describes the capabilities of the IP-blind voice/video relay, including 1:1/conference, codecs, and the join-token model. It is distinguishable from the null_* sibling set because it is the only tool about calls and relay capabilities. However, the description never states an explicit action like 'returns' or 'lists'—it speaks from the relay's perspective rather than the tool's.

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?

The description gives concrete context for use: because calls need a browser-based media client, an agent should use this information to read the relay's posture and hand a human the join flow. This effectively tells the agent when to treat calls as a human handoff rather than an agent-executable action. It does not name alternative sibling tools or state explicit when-not conditions, so it misses a 5.

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