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

Adds far more than the annotations: cost model ($0.01/call, first 25 free, failed calls free), error semantics (404 for missing contract, 422 for non-ERC-20, both uncharged), and the fact that reads are charged and non-idempotent in billing terms. Annotations already cover readOnly/destructive; the description supplies the pricing and failure behavior an agent needs to avoid wasteful retries.

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-loads the core definition and return shape, then purpose, then parameter/billing detail. Dense but every clause carries information; the pricing and error sentences slightly crowd an otherwise tight definition.

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?

No output schema, so the description must describe returns — it does (raw value, human units, unlimited flag). With a simple 3-param read tool, the description covers invocation, returns, cost, and error modes with nothing material 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%, so baseline is 3; the description goes further by defining acceptable token forms (ticker or 0x contract) and the failure semantics of a bad contract, which is a real behavioral consequence of the token parameter not captured in 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?

Explicitly states the verb/resource pairing: ERC-20 allowance on Ink, returning raw + token-unit amounts and an unlimited-approval flag. It distinguishes itself from the sibling ink_token_balance by naming it, which matters in a fleet of ~30 chain-prefixed allowance tools.

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 (pre-swap approval check, audit of risky open approvals) and an explicit exclusion routing balance queries to ink_token_balance. That is when-to-use, when-not, and the alternative all in one sentence.

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