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

Annotations already declare readOnlyHint and openWorldHint, so the safety profile is covered. The description adds crucial behavioral context beyond annotations: a per-call price of $0.005 USDC via x402, accepted payment chains, automatic payment by x402 MCP clients, and a free sample. It does not describe pagination or edge-case behavior for chainless addresses.

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 value proposition (one call, all chains, total USD), then payment info and the sample. The dense chain list and payment paragraph are justified, though the single long run-on sentence is harder to scan than separated clauses.

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 exists, and the description compensates by describing return contents: per-asset amount and USD, totals per chain, and total USD. Combined with the payment model and free sample, an agent has enough to call it correctly; minor gaps remain around error handling and rate limits.

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 both parameters are already documented. The description confirms the address parameter's multi-format scope ('EVM address', 'Solana address', 'Bitcoin and Tron addresses too') and the example value, but adds little on min_usd beyond what the schema already says. Baseline 3 is appropriate.

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 (portfolio retrieval) and resource (wallet across chains), enumerating exactly which chains and asset types are covered per address family. It is clearly distinguishable from siblings like evm_balance or btc_address because it aggregates across all major chains in one call.

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 explicit use cases ('agents that check a counterparty, a treasury or their own funds before acting') and explains payment mechanics and a free sample path. It does not explicitly name when to prefer a sibling such as evm_balance for single-chain checks, but the multi-chain aggregation scope implies it.

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