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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed-world), and the description adds genuinely useful context beyond them: a one-minute refresh cadence, 600+ market breadth, and a per-call cost of EUR 0.002. The cost disclosure is especially valuable for agent decision-making; only the return/pagination behavior is left unstated.

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 tight sentences with zero filler, and the core capability plus coverage is front-loaded before the optional filter and pricing details.

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 simple two-parameter read tool with no output schema, the description supplies the returned fields, freshness, coverage, filter behavior, and cost — nearly everything an agent needs. Only the semantics of the limit parameter are 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 coverage is 50%: symbol is documented in the schema and merely restated with an example in the description, while limit has no description anywhere despite a 1-1000 range and default of 100. The description does not compensate for that gap, so it adds little meaning 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 resource (latest crypto tickers) and enumerates the returned fields (last, bid, ask), plus the market coverage of 600+ markets. This clearly distinguishes it from get_crypto_meta or get_fx_rates, though it never names a sibling explicitly.

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 mentions the optional symbol filter with an example, which implies how to narrow a query, but gives no explicit when-to-use guidance or exclusions relative to alternatives like get_crypto_meta or get_equity_history. Usage is inferable rather than stated.

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