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

Annotations already mark the tool as read-only and idempotent, and the description adds substantial behavioral detail beyond that: values are sourced from live DEX liquidity, unquoted holdings are handled separately, results are sorted by value with a total, and the tool is priced at $0.02 per call with an x-credit-token header option and a one-free-call-per-day limit. Auth requirements and cost are disclosed explicitly. No contradiction with annotations.

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 description is front-loaded with the core output, then covers the edge-case behavior, input requirement, and cost/authentication in compact sentences. There is a minor redundancy between 'All tokens + USD value' and 'Complete token portfolio for a Base address with USD values', but no unrelated or fluff content is included.

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?

Even without an output schema, the description tells an agent what to expect: every ERC-20 plus native ETH valued in USD, sorted by value, with a total, and non-quoted holdings counted separately. It also covers the one required parameter, the network, pricing, authentication options, and lack of wallet/API-key requirements. Nothing needed to invoke the tool 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?

The schema has a single parameter, address, with the minimal description 'Wallet address'. The tool description adds meaningful context by specifying the address must be a Base address, which the schema alone does not convey. It also reinforces that this is the required input, providing enough meaning beyond the raw schema field.

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 opens with a specific verb-plus-resource statement: 'All tokens + USD value (reliable pricing) — Complete token portfolio for a Base address with USD values: every ERC-20 the wallet holds, priced from live DEX liquidity, plus native ETH — sorted by value with a total.' This precisely defines what the tool produces and distinguishes it from generic balance tools by emphasizing completeness and reliable pricing. It even clarifies an edge case: non-quoted holdings are listed and counted separately.

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?

The description clearly states the intended use case: obtain a complete USD-value token portfolio for an address on Base. It also gives prerequisites: only an address is required, and no wallet or API key is needed. It does not explicitly name alternative sibling tools or exclusions, but the 'complete portfolio' framing is enough context for an agent to select it.

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