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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false, so safety is covered. The description adds valuable context about data provenance ('each with its source and check date') and measurement ('measured all-in cost'), which informs the agent about data freshness and methodology. No contradiction with annotations.

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, dense sentence that front-loads the core content ('Base maker and taker rates') and lists all returned components efficiently. No filler or repetition; every element earns its place. Slightly long but appropriately packed.

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 read-only tool with one parameter and no output schema, the description covers the main return items comprehensively. It doesn't specify numeric formats or error behavior, but the list of data elements is sufficient for an agent to understand what to expect. The absence of an output schema is partially compensated by the detailed content list.

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 schema description covers the venue parameter fully (enum with example). The tool description adds the qualifier 'perp venue', which clarifies the domain but doesn't alter parameter semantics. Since schema coverage is 100%, the baseline of 3 is appropriate; the description provides minimal additional meaning beyond what the schema already gives.

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 precisely states the resource ('one perp venue') and enumerates the specific data returned: base maker/taker rates, volume fee ladder, leverage, funding terms, source/check date, and measured all-in cost of BTC/ETH market buys. This clearly distinguishes it from siblings like get_cheapest_venue (comparison) and get_funding (funding only).

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 purpose implies usage: call this when you need detailed fee breakdown for a specific venue. However, it does not explicitly mention when to use alternatives, such as get_cheapest_venue for cost comparison or get_volume_ranking for relative volume. No exclusions or when-not guidance is provided.

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