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

Given the annotations already declare readOnlyHint, idempotentHint, and destructiveHint false, the description adds useful behavioral context: it specifies the data source (DefiLlama), timeframes (24h/7d/30d), output characteristics (top DEXes, share, change), and pricing (free). It doesn't repeat annotation data, so this is valuable additional transparency.

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 description is compact and front-loaded with the core purpose. The extra details (source, price, optional scoping) are relevant, but the confusing phrasing around 'perps' and 'derivatives volume' slightly undermines clarity. Still, the overall structure is efficient and free of excess.

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?

The description provides a good overview of what the tool returns (top DEXes, share, change, timeframes, chain scope), which is helpful given there is no output schema. However, it omits the limit parameter semantics and gives an inaccurate type value, leaving gaps in the information an agent needs to make a fully informed call.

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?

The description adds some meaning for the type parameter (derivatives volume, aggregators) and chain (optional scoping), but it introduces a critical mismatch: it says 'type=perps' while the schema enum uses 'derivatives', which can mislead an agent into sending an invalid value. It also completely omits the 'limit' parameter, and with schema coverage at only 33%, the description fails to adequately compensate for the undocumented parameters.

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 clearly states it retrieves DEX trading volume rankings with specific timeframes, chain scoping, and output details (top DEXes, share, change). It distinguishes itself from siblings like cex_ticker or price by naming the resource (DEX volume) and data source (DefiLlama), making it easy for an agent to tell apart.

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 description gives clear context on when to use the tool (DEX volume queries) and how to scope it (by chain, type). It doesn't explicitly exclude alternatives or name neighboring tools, but the specificity of the purpose makes usage conditions reasonably clear.

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