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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so the safety profile is covered. The description still adds value beyond them by naming the asset types, the three chains, and reinforcing "Does not move funds" — though it says nothing about balance freshness or caching, which matters for on-chain reads.

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?

Four short sentences, front-loaded with the resource definition, then usage, then exclusion. "Does not move funds" partly restates readOnlyHint, but it is cheap reassurance in a payments context and nothing is padded.

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?

A zero-parameter, read-only lookup with an output schema, so return shape need not be described. What an agent needs — what is read, on which chains, when to call it, and which sibling to prefer instead — is all present.

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 tool takes no arguments, so the baseline is 4. The description correctly spends no space on parameter explanation and instead uses that room for scope and routing information.

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-only on-chain USDC/USDT balances), names the wallet owner and the three supported chains, and explicitly contrasts itself with get_spend_balance. An agent can distinguish it from the VAPT spending tool without opening either schema.

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?

"Use this to tell the user how much they can spend" gives a concrete triggering situation, and "Separate from get_spend_balance (VAPT caps)" supplies an explicit alternative with its distinguishing condition. The trailing "Related:" list is only names without conditions, so not every sibling routing is spelled out, but the primary one is.

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