Sign-in profile & quota usage

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

Annotations already declare readOnlyHint, idempotentHint and non-destructive, and the description adds genuinely new context: the tool makes no network call, so it is free to invoke and safe as a pre-check, and it reports session-level counters plus limiter state. Not a 5 only because it says nothing about the shape or staleness of those counters.

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?

Two clauses front-load the three things returned, and the trailing 'Makes no API call' is a high-value single sentence that earns its place. 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?

An output schema exists, so return values need no elaboration, yet the description still names the three data points an agent cares about. For a zero-param, read-only diagnostic tool this is fully adequate.

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?

Zero parameters, so the baseline of 4 applies. The description correctly implies nothing is configurable, consistent with the empty schema.

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 names a specific resource class (sign-in scope profile, session request count, rate limiter state) and explicitly notes it makes no API call, which cleanly separates it from the many read siblings that do hit the API. It never names a sibling directly, keeping it short of a 5.

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 content implies diagnostic usage — an agent would infer this is the pre-flight check for whether it has write scope or has hit its limiter — but the description never states when to call it or when not to. There is no explicit routing to or away from alternatives such as the list/get tools.

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