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

Annotations already declare readOnlyHint=true and openWorldHint=false, so safety is covered. The description adds genuinely useful provenance — fees are entry-tier and were verified against each venue's own docs on a recorded date — which tells the agent how much to trust the numbers. It says nothing about ordering, pagination, or result size, but for a static zero-param list that is a minor omission.

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?

A single sentence, front-loaded with the resource and then the returned fields. It is dense but every element listed is meaningful output information, with no filler or hedging.

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?

With no output schema, the description carries the burden of describing the return shape, and it does so by enumerating the four per-venue attributes. What is missing is the differentiation an agent needs to choose this over siblings, not the call mechanics.

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 tool takes no parameters (0 count, 100% coverage), so there is nothing for the description to disambiguate; baseline 4 applies.

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 perp DEXs we cover' names the exact resource set and, by listing the per-venue attributes (order book type, maker/taker fees, verification date, signup link), makes clear this is an enumeration of covered venues. It does not state a verb or contrast with siblings such as best_venue or trading_cost, so it falls 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?

There is no when-to-use guidance at all — nothing tells the agent to call this before trading_cost, best_venue, or signup_link, nor that it is the right entry point when the user asks which venues exist. The relationship to the closely related signup_link sibling is left entirely implicit.

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