fetch_mark_price

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

With no annotations, the description carries the full behavioral burden. It does disclose the key trait that this is a public, unauthenticated read, which is genuinely valuable; but it says nothing about error behavior for an invalid market_id, snapshot freshness, or whether the result reflects live or last-known state.

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 the action and scope, followed by the access constraint. Nothing is redundant or padded.

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 single-parameter read with a fully documented schema and no output schema, the description covers action, scope, and auth — nearly enough. The remaining gap is the absence of any disambiguation from get_mark_price, which matters in this densely populated sibling set.

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 100% and the schema already documents market_id with an example ("BTC-USDX-PERP"), so the baseline is 3. The description's "one market" phrasing adds no syntax or format detail beyond what the schema provides.

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 the current mark price") and constrains scope to "one market," which is clear. However, it does not distinguish itself from the near-identical sibling get_mark_price (or from fetch_tickers/get_ticker), so an agent cannot tell from the text alone which of these to call.

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?

"Public — no credentials needed" gives useful access context, but there is no when-to-use guidance and no routing versus the sibling get_mark_price or the broader ticker tools. Usage is only implied from the name.

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