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

readOnlyHint=true already establishes the safe-read profile, and the description adds genuinely useful context beyond it: the payload is deliberately source-opaque and contains no source-level detail, which is decision-relevant information about what this tool will and will not return. It does not cover error behavior or any freshness/latency characteristics, keeping it below 5.

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 tightly front-loaded sentences: the purpose and output shape come first, the disambiguation rule last. The ten-field enumeration is long but earns its place because no output schema exists to carry that information.

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, the description compensates by enumerating the exact returned fields, and the read-only annotation covers the safety profile, so an agent has enough to call it correctly. Remaining gaps — failure mode for an unknown index and whether the value can be stale — are minor.

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 index_id parameter already documents its format with concrete slug examples ('FLOPS-H100-OD'). The description adds no syntax, aliasing, or lookup guidance beyond the schema, so the 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?

The description gives a specific verb ('Resolve') and resource ('FLOPS index') and states exactly what is produced: a 'source-opaque PUBLIC citation payload' with an enumerated field list. The clause 'Prefer get_index when you intend to CITE the value' orients it against get_price without the agent needing to open either schema.

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 provides a clear selection rule — use this tool when you intend to cite the value — which implicitly steers the agent away from get_price for citation workflows. It stops short of naming the alternative explicitly or stating exclusions/error conditions (e.g., unknown index_id), so it is strong but not exhaustive.

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