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

Annotations already cover read-only/non-destructive, and the description adds value beyond them: the 422-and-uncharged error path, the $0.01/call price, the first-25-free allowance, and the note that repeats are not free — which coherently explains the idempotentHint=false. 'Changes nothing' is consistent with readOnlyHint=true, so there is no contradiction.

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 core purpose and alternative routing are front-loaded, and most sentences carry unique information. The billing tail (price, free tier, card key) is useful but slightly crowds the single-paragraph format; it could be trimmed without losing callable guidance.

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, and the description lists exactly what comes back (name, symbol, decimals, total supply), so the agent knows the return shape. Combined with error behavior, pricing, and input formats, nothing material needed to call 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 schema already describes the ticker-or-address input, so the baseline is 3. The description earns a point above baseline by adding a concrete worked example address and the consequence of passing a non-contract address, which the schema does not convey.

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 and resource — look up name, symbol, decimals and total supply of an ERC-20 contract on Base — and notes the data is read live from the contract. It explicitly distinguishes itself from the sibling base_token_balance, so an agent can route correctly without inspecting either 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?

Gives two concrete use cases (identify an unknown token address, format raw amounts) plus an explicit exclusion pointing to base_token_balance for holder balances. It also names a failure mode (non-ERC-20 address returns 422) that tells the agent when the call is inappropriate.

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