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

Without annotations, the description carries the full transparency burden. It discloses the exact return fields, clarifies that confidence is a label not a numeric weight, and explicitly states that it 'carries no methodology or source attribution by design.' These are important behavioral traits that go beyond schema. It doesn't cover error handling or staleness, but the disclosed caveats are significant.

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 compact and front-loaded with the core action. Each sentence adds value: purpose, return structure, use case, confidence semantics, and attribution limitation. There is no fluff or repetition, making it highly efficient.

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 single-parameter tool with no output schema, the description is remarkably complete. It covers what the tool does, what it returns, when to use it, and notable caveats. The inclusion of the return fields compensates for the lack of an output schema, and the caveat about missing attribution helps set expectations fully.

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 already fully describes the single parameter 'slug' with its accepted formats. The description adds no additional parameter-level meaning beyond what the schema provides. With 100% schema coverage, a baseline of 3 is appropriate.

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 clearly states a specific verb and resource: 'Fetch the current published value for a FLOPS compute price index.' It also distinguishes from siblings by framing it as the 'Cheapest way to answer what does X trade at right now?' This makes it clear this is a lightweight price lookup compared to tools like get_index or search_indices.

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 provides clear usage context: it is the 'cheapest way to answer what does X trade at right now,' which implies a quick, minimal-data need. However, it does not explicitly name alternative tools or say when not to use it, so it earns a 4 rather than a 5.

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