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

Annotations cover the safety profile (readOnly, idempotent, openWorld, non-destructive), and the description adds substantial context beyond that: the actual data sources, the session taxonomy returned, explicit 'indicative, never an exchange quote' caveat, 503 error condition when no source has liquidity, and a pay-per-call cost of 0.01 USDC via x402 across named chains.

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?

The purpose and asset class are front-loaded, and the trailing sentences carry distinct information (caveat, error behavior, cost). The first sentence is a dense run-on with many stacked clauses, which is slightly heavy, but nearly every element earns its place.

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 single-parameter pricing tool with an output schema already present, the description supplies everything an agent needs: scope, sources, session/return semantics, error behavior, and payment model. Nothing needed to invoke it correctly is missing.

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?

Schema coverage is 100% and the single symbol parameter is already documented with examples, so the baseline is 3. The description adds example tickers (TSLA, NVDA, S&P 500, Nasdaq) but these largely restate the schema examples (which use SP500, XYZ100), adding little new meaning.

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?

States a specific verb/resource and scope: an indicative 24/7 price for US stocks or indices sourced from Hyperliquid stock perps and a tokenized-stocks DEX. It clearly separates itself from crypto-price siblings like get_btc_price, get_eth_price, get_sol_price by naming the equity asset class explicitly.

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?

Implied usage is clear from the framing ('Weekend price for US stocks', session labels including weekend), so an agent can infer it is for off-hours equity pricing. However, it never explicitly says when to use this versus alternatives such as get_tradfi_perps, get_spot, or get_tradfi_radar, leaving routing to inference.

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