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

Annotations only declare readOnlyHint=true; the description adds genuinely new behavioral facts: no authentication required and the presence of a 'delayed' flag per row, which hints at data freshness characteristics. It stops short of pagination, rate limits, or result-size limits, so it is not exhaustive.

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?

Three sentences, front-loaded with purpose, then return shape, then usage. Every sentence carries distinct information and there is 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?

With no output schema, describing the return envelope and row fields is exactly the right compensation, and the no-auth note removes a common pre-call uncertainty for a discovery tool. Nothing an agent needs to call it correctly 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?

Schema description coverage is 100% and the single family_filter parameter is fully documented in the schema, including examples and case-sensitivity. The description says nothing about the filter, so it adds no value here; baseline 3 applies.

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?

States a specific verb and resource ('List all public FLOPS compute-price indices') with a clear scope qualifier ('public'). An agent can distinguish this enumeration tool from get_index/search_indices without inspecting schemas.

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?

Explicitly states the use case: 'Use this to discover available indices before calling get_price or verify,' which gives a clear call-ordering signal. It does not, however, contrast itself against the sibling search_indices or get_index, which is the one remaining ambiguity in a family of four lookup tools.

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