Show which Roblox client this session targets

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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so the safety profile is covered; the description restates it but also adds useful behavioral detail beyond the annotations, namely that the result reports current selection and can indicate ambiguous or offline resolution. The 'On failure: inspect tool-schema' pointer is also helpful.

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 purpose is correctly front-loaded, but the trailing metadata block is partly redundant: 'idempotency=read-only' and 'Safety: read-only' restate the readOnlyHint/idempotentHint annotations, and 'Requires: none' is derivable from the empty schema. 'Phase: observe; cost=low' does add value, so the padding is moderate rather than severe.

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 zero-argument read-only observation tool with no output schema, the description covers what it returns (client selection, ambiguity, offline state), when to reach for it, and where to look for field details, which is nearly everything an agent needs. Only the exact return shape is left to the tool-schema pointer.

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 (baseline 4) and schema coverage is 100%, so there are no parameter semantics to explain. The empty 'Signature: {}' correctly signals a no-argument call.

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 description states a specific verb and resource: it reports which live Roblox client THIS session resolves to, including selection state and ambiguity/offline status. The phrase 'THIS session currently resolves to' implicitly separates it from list-clients and select-client, but no sibling is named explicitly, so it stops short of the top score.

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?

It gives a clear usage condition: 'Use it to confirm routing before running code, especially when multiple games are connected or after a rejoin.' That is concrete when-to-use context, but there is no explicit when-not guidance and no alternative tool (e.g. list-clients) is named.

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