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

Annotations already declare readOnly, openWorld, and idempotent, so the safety profile is covered. The description adds genuinely useful behavioral context beyond them: the source is public price feeds, results are cached for 60 s (implying staleness), and the result carries a signed receipt (verifiability). It stops short of stating rate limits or error behavior for unknown symbols.

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 short sentences, front-loaded with what is priced and from where, then the cache and receipt facts. No filler and nothing repeated.

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?

An output schema exists, so return-value explanation is not required, and the signed-receipt mention is a helpful pointer. Caching and source are disclosed, but error handling for unrecognized symbols and any rate limiting are absent.

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 there is only one parameter, so the schema already documents the ticker-vs-CoinGecko-id duality fully. The description restates the same accepted forms without adding format or validation detail, matching the baseline 3 for a schema-complete tool.

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+resource: spot USD price for a crypto ticker or CoinGecko id. The 'USD' and 'crypto ticker' qualifiers implicitly separate it from fiat siblings like fx_spot_price_oracle, but it never names or explicitly contrasts any sibling, so disambiguation is left to inference.

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?

No when-to-use guidance, no when-not-to-use, and no mention of alternatives such as check_price or fx_spot_price_oracle. The only contextual detail is the data source and cache TTL, which is not routing guidance.

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