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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint, so the safety profile is fully covered structurally. The description adds the semantic content of the response (what the four USDC buckets mean), but says nothing about scoping behavior such as which chain or subaccount the balance is drawn from, or freshness/latency.

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 short fragments with no filler, and the payload contents are front-loaded before the example query. The colon-fragment style ("An account's USDC:") is terse to the point of being slightly clipped, but nothing is wasted.

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?

An output schema exists, so return values need not be explained, and the description still summarizes the response breakdown usefully. For a single-parameter read tool with full annotation coverage, what remains is sufficient to call it correctly; only the balance scope/freshness is left unstated.

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 a single required address parameter that is fully documented including the regex pattern. The description only alludes to the address through the example question and adds no format, casing, or address-type nuance beyond the schema. Baseline 3 applies since the schema does the heavy lifting.

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?

The description names the resource (an account's USDC) and enumerates the exact breakdown returned: available to trade, in positions, reserved by orders, unrealized PnL. That distinguishes it from generic siblings like get_account or get_positions, which don't claim to return a USDC breakdown. It stops short of a 5 because the verb is only implied by the fragment structure rather than stated.

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 embedded example question ("How much USDC does 0x… have?") gives a concrete trigger condition for selecting this tool. There is no explicit exclusion or named alternative for adjacent needs such as position-level or portfolio-level queries, so it is clear context without routing rules.

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