fuel_data_status

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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false, so the safety profile is fully covered by structured data. The description adds the diagnostic purpose (checking credentials, stations, cache age to diagnose empty results), which is useful context beyond what annotations provide. However, it doesn't describe the output format or how the agent should interpret the return values.

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 concise sentences with zero waste. The description is front-loaded with a clear verb ('Check') and immediately follows with the diagnostic use case. Both sentences earn their place.

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-parameter diagnostic tool with a full safety profile from annotations and an output schema, the description is reasonably complete. It states what's checked (credentials, stations, cache age) and when to use it (diagnose empty results). The tool is simple enough that this level of detail is 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?

The tool has zero parameters and 100% schema description coverage (trivially, since there are no properties). The baseline of 4 for zero params applies here. The description doesn't need to document parameters that don't exist.

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 uses a specific verb ('Check') with clear resources (server's data: credentials, stations, cache age) and explicitly states its diagnostic purpose. It clearly distinguishes from sibling tools, which all perform lookups or queries, whereas this tool inspects the data layer itself.

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 explicitly gives a usage context: 'Use this to diagnose empty results.' This tells the agent when to invoke this tool versus the sibling lookup tools. However, it doesn't provide exclusions or when-not-to-use guidance, which is a minor gap for a diagnostic tool.

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