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

With no annotations provided, the description carries the full burden of disclosure. It clearly states that the tool returns auth status, tier, server version, time, and rate-limit state, and explicitly notes that it does not consume extra quota beyond the call itself. This covers the key behavioral traits an agent needs to know for a status probe. It does not explicitly say it never modifies anything, but the read-only nature is strongly implied by the diagnostic framing and the listed outputs, so the slight gap is minor.

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 description is about 90 words and is well-structured: it opens with the core question, then lists outputs, then gives usage guidance and the quota note. Every sentence contributes new information, and the most important guidance ('call this first when other tools fail') is front-loaded near the middle rather than buried at the end. It is slightly longer than strictly necessary, but the density of actionable detail justifies the length.

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?

Given that the tool has no parameters, no output schema, and no annotations, the description needs to fully explain what the agent will get and when to use it. It does exactly that: it enumerates all the returned data categories, explains how to interpret them for troubleshooting, and explicitly promises no extra quota consumption. The sibling set is large and all getter-like, so this description successfully carves out a unique diagnostic role. Nothing essential is missing.

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 has zero parameters, so schema coverage is trivially 100%. The description goes beyond the empty schema by explaining what the returned fields mean (key kind, tier, time, rate-limit state) and how they map to troubleshooting actions. With no parameters to document, a baseline of 4 is appropriate; the description adds semantic value about the output context even though it cannot describe input semantics.

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 opens with a customer-facing question ('Am I connected, and what can this key do?') and then enumerates exactly what it returns: auth status (key kind and tier), server version, current UTC time, and rate-limit state. This is a specific verb+resource with no ambiguity. It also distinguishes itself from the many sibling getter tools by positioning itself as the diagnostic endpoint to call when other tools fail, which clearly sets it apart from the rest of the arena_* family.

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 explicit, actionable guidance: 'Call this first when other tools fail' and then tells the agent how to interpret results by separating auth problems (reconnect), tier problems (upgrade), and rate limits (wait) from real outages. It also states that the call itself does not consume extra quota, which is a practical constraint. This is textbook when-to-use and when-not-to-use guidance.

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