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 the return denomination detail (wei and whole coins), which is useful context beyond the annotations, though no rate-limit or address-validation behavior is disclosed.

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?

A single tight sentence, front-loaded with the resource and ending with the return format. Zero waste.

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?

Adequate for a simple read-only tool with fully documented params and no output schema, but it omits the wei-to-coin conversion/decimals context and any error behavior (e.g., invalid address), leaving some gaps.

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%, with each parameter documented and chain enum provided, so baseline is 3. The description adds nothing about parameter format or the multi-chain scope beyond what the schema explains.

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 resource (native-coin balance), the target (an address on an EVM chain), and the return format (wei and whole coins). Clearly distinct from siblings like chord_find_token or get_block_number.

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 by the narrow purpose but there is no explicit when-to-use-vs-alternatives guidance. Siblings are mostly unrelated, so routing risk is low, keeping this at minimum viable.

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