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

Beyond the annotations (readOnly, openWorld, destructive=false), the description discloses the pricing source (deepest Uniswap v3 pool), that reads are live from the chain, that unpriceable assets are returned rather than silently dropped, and a full cost model ($0.005/call, 25 free, failed calls free, every call charged). The per-call charge also explains the idempotentHint=false in practical terms.

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 and scope are front-loaded in the first sentence, and the exclusion and usage guidance follow. The closing pricing/billing sentence is long and carries some duplication ('charged, so repeats are not free'), but the cost information does affect agent behavior, so it largely earns its place.

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, so the description carries the return contract itself: holdings, a total, and anything that could not be priced. Combined with chain coverage, token limits, pricing source and cost model, an agent has everything needed to call it and interpret the result.

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 parameters and their defaults are already documented; the description adds a realistic example address illustrating the expected format and restates chain coverage and the 20-token cap, which is partly redundant with the schema. Baseline-plus-example is the right level here.

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?

The description names a specific verb+resource (USD value of a wallet) and pins down scope precisely: four chains, native ETH plus named major tokens, up to 20 user-supplied tokens, priced from Uniswap v3. It explicitly rules out being a full token inventory, which separates it from siblings like wallet_audit, token_report and price_tokens.

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?

It states the concrete decision context ('Use to check what a wallet is worth before trading, lending or paying') and a negative bound ('Not a full token inventory'), which tells the agent when this tool is the wrong choice. It does not, however, name the alternative tool to use for a full inventory, so the routing is implied rather than explicit.

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