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

Annotations already declare readOnlyHint=true, destructiveHint=false, idempotentHint=false and openWorldHint=true. The description adds real context beyond them: $0.01/call pricing, first 25 free, failed calls free, 400 on malformed addresses with no charge, and the explicit note that repeats are not free. That is genuinely useful, though 'reads or computes only and changes nothing' partly restates readOnlyHint.

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?

Purpose is front-loaded in the first clause and the sibling routing follows immediately. The trailing pricing/credits sentence is long and dense; it is useful for cost-aware selection but takes up nearly half the text, keeping this just short of a 5.

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 no output schema, the description still tells the agent what comes back (direction, counterparty, amount, transaction, newest first, up to 50) and what errors look like (400 on malformed address). Complete enough to call correctly; only the response shape's exact field types are unspecified.

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%, so the baseline is 3, but the description still adds meaning: default token is USDC on Celo, blocks range 1-2,000 with default 1,000, the 50-result cap, newest-first ordering, and a concrete example address. It does not explain the ticker-vs-contract form of `token` beyond the schema.

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 (list a wallet's recent ERC-20 transfers on Celo) plus scope details: in and out, last N blocks, newest first, cap of 50. It explicitly names the sibling it is not (celo_token_balance) and the default token (USDC), 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?

Gives concrete use cases ('confirm a payment arrived or see what was sent') and routes the balance case to celo_token_balance by name. When-to-use and the primary alternative are both explicit rather than inferred.

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