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

Goes well beyond the annotations: it explains the unusual readOnlyHint=false ('not marked read-only because each call is charged'), discloses the pricing model ($0.005/call, first 25 free, failed calls free, x402 USDC or card key), and describes the computation ('read live from the chain', 'priced from its deepest Uniswap v3 pool'). It also states failure behavior by noting unpriceable tokens are returned.

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 what the tool returns and its scope before pricing and caveats. Dense but largely waste-free, though the pricing clause runs long and the semicolon-chained sentences could be tightened without losing information.

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 carries the return burden and does: 'Returns holdings, total and anything that could not be priced.' Chain coverage, default token set, cost model, and the read-only rationale are all present, leaving no material gap 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%, so the baseline is 3, but the description adds real semantics: it names which tokens are included by default (native ETH, USDC and WETH on all chains, common Base tokens on Base) and restates the up-to-20 extra-token cap. The chain parameter's meaning is left to the schema's enum, which is already sufficient.

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 resource and metric ('USD value of a wallet') with the supported chains enumerated inline, and explicitly bounds the scope with 'Not a full token inventory,' which separates it from inventory-style siblings like wallet_audit or token_report. An agent can tell what it produces and what it does not.

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 an explicit trigger context: 'Use to check what a wallet is worth before trading, lending or paying.' It also implies a negative case via 'Not a full token inventory,' but it never names an alternative tool (e.g. wallet_audit for full holdings) or states when to prefer a different pricing tool, so routing is clear but not fully closed.

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