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

Annotations already declare readOnly/idempotent/non-destructive, and the description goes well beyond that: 422 for an unsupported pair with the 'not charged' caveat, typical latency of 0.2-1s, $0.002 price, a 10-reads-per-IP-per-UTC-day free tier, and a prompt-injection warning about treating returned page text and on-chain strings as untrusted. This is unusually rich disclosure for a paid, open-world tool.

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?

Front-loaded with the core verb+resource in the first clause, then alternatives, error/cost/latency facts, and a safety note. Dense but each sentence carries actionable information; the pricing/free-tier detail makes it slightly heavier than strictly necessary.

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 an output schema present, return values need not be described. The description covers the remaining gaps an agent needs: alternatives, failure semantics, cost, latency, free tier, and untrusted-data handling. Nothing material is missing for correct invocation.

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 both params carry enum lists with descriptions already covering the pair allow-list and the Ethereum/Base-only constraint. The description adds only the pair×chain failure mode (422 on an unavailable pair), so the baseline 3 is appropriate.

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 ('read a token price from a Chainlink on-chain price feed') and immediately frames the scope qualitatively as a deterministic oracle answer rather than a DEX spot price. It names two sibling tools it is not, so an agent can distinguish it without opening a schema.

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?

Explicitly routes alternatives: use get_swap_quote for a DEX quote of any token, and get_solana_token_price for Solana. Combined with the 'oracle not DEX spot' framing, the selection condition between oracle pricing and DEX pricing is clear.

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