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

Goes well beyond the readOnly/openWorld annotations by disclosing signature semantics (v1 does not cover tier/confidence/dispersionBps/interval/sources/engine/cadence; v2 signs them with the price), that priceText must be preserved verbatim, and the critical failure mode that a stale or unavailable response means no price, never zero. This is exactly the kind of behavioral context annotations cannot carry.

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?

Front-loads verb, resource, and endpoint, then layers verification and signing caveats. Four dense sentences with little waste, though the v1/v2 signing sentence is heavy enough that it borders on overload for a single-parameter read tool.

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?

Even though an output schema exists, the description fills the gaps that schema cannot: which returned fields are signed by which version, how to forward the print, and how to interpret an empty/stale result. An agent has everything needed to call and correctly chain this tool.

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 symbol parameter is already documented with example tickers, so baseline 3 applies. The 'coverage changes: use list_index_assets' note hints that some symbols may be uncovered, but it does not explain symbol format or validity rules beyond the schema.

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 ('Get a current signed crypto index price') plus the underlying endpoint, which immediately distinguishes it from history/batch siblings. The mention of verify_print and list_index_assets anchors it in the tool family so an agent can place it without opening a 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?

Gives clear follow-up routing: pass the whole print (v2 included) to verify_print, and use list_index_assets to discover assets. However, it never says when to prefer this over get_index_batch or get_index_history, so selection among the price-fetch siblings is left to inference.

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