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

Annotations already declare readOnlyHint=true, so the agent knows this does not mutate state; the description reinforces that by framing it as a quote 'before committing'. Beyond that it adds nothing behavioral — no indication of what the quote returns, whether it expires, or any rate/ownership constraints. With the safety profile already carried by annotations, this is a minimum-viable 3.

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, front-loading the core action before the semantic clarification. Every clause earns its place.

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 4-parameter trading tool with no output schema and 0% schema description coverage, the definition is thin. It does not explain the return payload (a price/quote), the role of amount/address/market, or any constraints, so an agent is under-informed about how to call and interpret it.

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%, so the description carries the full burden, yet it only clarifies the 'side' enum ('a buy spends the stock; a sell spends the coin'). The three other parameters — amount, address, and market — receive no explanation, and even 'side' is described in symbolic terms rather than as a spending-currency notion tied to the enums.

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 states a specific verb and resource ('Price a buy or sell against one of a coin's stock markets'), which is clearly distinct from the read-only informational siblings (list_coins, get_coin, list_markets, fee_schedule). It also adds a purpose qualifier ('before committing') that clarifies this is a preview step. No sibling is explicitly named, but none is close enough to require differentiation.

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?

The phrase 'before committing' implies the tool is used as a pre-execution quote, which is useful implied timing guidance. However, it never states prerequisites (e.g., required auth/address ownership) or explicitly contrasts this with any alternative action, leaving the 'when' to inference.

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