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

Annotations already declare readOnly, idempotent, openWorld, and non-destructive, so the safety profile is covered. The description adds useful context: it is free, reads a single block snapshot, caps tokens at three, and performs no discovery or valuation. It does not describe the returned observation shape or failure behavior, so it adds moderate rather than rich context.

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?

Two tight sentences with the cost signal front-loaded and the scope constraints following immediately. No filler or restatement of the tool name.

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 should hint at the return shape, but it only implies a block-scoped observation without describing fields like native_wei, tokens, or checked_at. Safety and scope are adequately covered by annotations plus the description, but the return contract is a gap.

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 description coverage is 0%, so the description must carry the load, and it does explain the token cap (three), the single-block semantics, and the purpose of the baseline parameter. It leaves the chain enum values and wallet format unexplained, which the schema only partially covers via the enum.

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 and resource: read live native and up to three specified ERC-20 balances at one block. It also scopes out what it does not do (no discovery, valuation, or alerts), which separates it from the valuation/quote-oriented siblings.

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 'compare a caller-held baseline' clause and the explicit exclusions ('no automatic asset discovery, valuation, or scheduled alerts') tell the agent when this tool fits and when it does not. It stops short of naming an alternative sibling for the excluded cases, so it is not a full 5.

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