tools

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

With no annotations, the description carries full disclosure duty and handles the important traits well: it is free, needs no account, and reads a live public API. It stops short of stating rate limits, caching/freshness guarantees, or failure behavior, so the operational profile is only partly covered.

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 tight sentences, front-loaded with what is returned and followed by cost/auth facts and the scope boundary. Every clause carries information; nothing is redundant padding.

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 correctly compensates by listing the returned fields, and it clarifies the paid-route boundary. The one unresolved point is which market row is returned given there is no selector parameter, which leaves a small ambiguity for the agent.

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 zero parameters, and the schema is fully self-describing at 100% coverage, so the baseline of 4 applies. No parameter-level meaning is required from the description.

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 states a specific verb and resource ('Get one live row from Lighter's perpetuals markets') and enumerates the exact returned fields (symbol, mark price, 24h change %, 24h volume USD). An agent knows precisely what it gets back without opening anything else, and there are no siblings requiring differentiation.

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 gives clear context for use ('Free, no account, reads Lighter's public API live') and draws an explicit exclusion boundary: the fuller funding-rate/cross-exchange-spread snapshot lives on a separate paid HTTP route not exposed over MCP. That tells the agent when this tool is and isn't the right choice, though it doesn't spell out a positive use scenario in so many words.

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