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

With no annotations supplied, the description carries the full burden and does real work: it declares the tool is read-only on public chain data, requires no private key, and discloses the cost model ($0.001 via x402 in production, free inside the MCP playzone). It falls short of a 5 because it says nothing about failure behavior for malformed addresses or what happens when a wallet holds neither asset.

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 core purpose is front-loaded in the first sentence and the safety constraint follows immediately, which is good ordering. The trailing attribution 'By OMENZ' and the long parenthetical about playzone and production endpoint add context but also clutter and could be trimmed without losing agent-relevant meaning.

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?

For a one-parameter, output-schema-less read tool this covers the essentials: what it returns (USDC and ETH balances), that it is non-custodial, and its cost surface. The only meaningful gap is address input format, which neither schema nor description specifies.

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 single address parameter has 0% schema description coverage, so the description must compensate and only partly does. 'Any wallet on Base' narrows the domain to Base addresses, but it gives no format guidance (hex 0x address vs. ENS name) or validation rules, leaving the agent to guess what a valid input string looks like.

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-like action and resource: read USDC and ETH balances of any wallet on Base. It names the chain, the two assets, and qualifies the data as public chain data, and the phrase 'Never moves funds' implicitly separates it from the mutation-flavored siblings wallet_spend and wallet_runway.

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?

Usage is implied rather than stated: an agent can infer this is the read-only balance lookup, and 'Never moves funds' rules out transfer use cases. There is no explicit when-to-use clause, no when-not clause, and no named alternative for related questions like runway or spend history.

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