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

Annotations already declare readOnly, idempotent, closed-world, non-destructive behavior, so the safety profile is covered. The description adds one genuinely new behavioral fact not present in any structured field: a cost of EUR 0.002 per call, which matters for agent budgeting. It stops short of saying anything about result size, pagination, or whether the metadata is static or refreshed.

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 with no filler, and the resource identity is front-loaded before the cost caveat. The parenthetical "coverage and market descriptors" is the only slightly soft phrase, but it earns its place by sketching the return shape in the absence of an output schema.

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 no-required-param read tool with annotations covering safety, the definition is close to sufficient, and the cost disclosure is valuable. Missing are the meaning of the limit parameter and any indication of what the returned metadata looks like, which matters because there is no output schema to fall back on.

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 0% for the single parameter, so the description carries the full burden of explaining the limit argument, and it says nothing. It is unclear whether limit caps markets, coverage entries, or descriptor records, nor what the default of 50 yields in practice. With one undocumented parameter, this is a real gap rather than the zero-parameter baseline case.

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 identifies the resource as "crypto market metadata" and parenthetically names its contents (coverage and market descriptors), which is more specific than the title alone. However, it is a noun phrase with no verb and does not contrast itself with siblings such as get_crypto_tickers or list_sources, so an agent must infer the boundary between metadata and actual market data.

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?

There is no statement of when to reach for this tool versus get_crypto_tickers, get_commodities, or list_sources, and no prerequisites or preconditions are given. The only practical guidance present is an incidental cost note, which is not usage routing.

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