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

Annotations already establish this is a read-only, idempotent, non-destructive, closed-world operation, so the bar is lower. The description still adds context the annotations do not: the venue-omission resolution rule ('the busiest market wins') and a precise manifest of returned metrics. It omits error behavior for bad symbols/venues and how many 'latest trades' come back, keeping it below a 5.

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?

The payload-carrying content is front-loaded in the first sentence, followed by the shortest possible calling instruction and an example. It is dense but every clause names a returned data point or a usage rule. The example slightly duplicates the schema, which is minor waste rather than filler.

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?

There is no output schema, so the description correctly carries the return-value burden by listing every reported metric. With only two well-documented parameters and annotations covering the safety profile, an agent has enough to call it correctly. Gaps are limited to failure modes and trade-count semantics for the 'latest trades' section.

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%, so the baseline is 3. The description adds a worked example mapping the abstract 'market' field to a real value ('BTC') paired with a valid venue, which clarifies symbol format and the optional-venue combination beyond the schema text. Its restatement of the 'busiest' default duplicates what the venue property already says, capping the gain.

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 a single, concrete resource (one perpetual futures market on Sui) and enumerates exactly what it reports: mark/index price, 24h change and volume, open interest, funding, max leverage, fees, recent trades and backing pools. That inventory separates it from siblings like price, candles and order_book without naming them. It never states an explicit verb ('fetch'/'get'), which keeps it just short of a 5.

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 tells the agent to pass a symbol and that venue is optional because the busiest market wins, which is real invocation guidance. However, it gives no when-to-use/when-not guidance relative to overlapping siblings (price, candles, order_book) and does not say what happens for an unknown symbol or unsupported venue. Usage is implied rather than routed.

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