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

Annotations already declare readOnly, idempotent, openWorld, and non-destructive, so safety is covered. The description adds a genuinely useful behavioral fact beyond the structured fields: this is a paid call costing 0.005 USDC via x402 and the accepted payment chains, which an agent must know before invoking.

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 what the tool returns and reserving the second for cost. No filler, no redundancy.

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?

An output schema exists so return values need not be explained, and the description covers both content and payment cost. Complete for a zero-parameter, paid read tool, with only the deliberate sibling-routing guidance left implicit.

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 clarify; the baseline for a no-param tool applies. The description correctly avoids inventing parameter guidance.

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 verb-implied resource (a market snapshot) and enumerates its exact contents: SOL+BTC prices, funding rates, and Fear & Greed. The phrase 'in one call' distinguishes it from the single-purpose siblings (get_btc_price, get_sol_price, get_fear_greed, get_funding_rate), though it never explicitly names them.

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?

'In one call' implies this is a bundle useful when several of these datapoints are needed at once, which is reasonable implied guidance. However there is no explicit statement of when to prefer this aggregate over the individual sibling tools, nor any when-not-to-use condition.

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