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

Annotations already declare readOnlyHint and openWorldHint. The description usefully adds behavior the annotations don't cover: the tool is a paid endpoint costing $0.05 (50000 atomic USDC on Base) via x402, which is critical for an agent to know before calling. However, it says nothing about data freshness, staleness, or what happens if payment fails.

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 short sentences, front-loaded with purpose followed by cost. No filler. Minor deduction because the payment mechanics (x402, atomic units, chain) are stated telegraphically without explaining what the agent must do to satisfy them.

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 carries the burden of explaining return values, and 'as JSON' is thin — no indication of the signal fields, count, or shape. The payment precondition is well covered, but the payload an agent will receive remains opaque.

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, so there is nothing for the description to disambiguate; baseline for a parameterless tool applies. The relevant 'parameter' is really the payment precondition, which the description does address.

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 names a specific resource ('Current trade signals') and its source ('the desk signals file'), so the agent knows exactly what it retrieves. It doesn't need sibling differentiation because no other sibling is a trade-signal source, but it also relies on 'signals' being self-explanatory rather than defining the content.

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 statement of when to use this tool versus alternatives, nor any guidance on how often to poll or whether the signals are time-sensitive. The only implicit usage signal is the price line, which tells the agent the call costs money but not when the cost is justified.

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