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

Despite having readOnlyHint annotation, the description adds valuable context: it lists asset categories, chain coverage, sorting by USD value, a hard limit of 20 holdings, and the inclusion of native ETH. This goes well beyond the annotation to set expectations about the returned data.

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?

Three sentences, each providing distinct information: overall function, coverage/scope, and a usage caveat. No wasted words, and the most important detail is front-loaded.

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?

With an output schema present and read-only annotation, the description fully covers the tool's behavior, including limits, sorting, and coverage. It provides enough context for an agent to decide when to call it.

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?

Both parameters have detailed descriptions in the schema (wallet address, chain_id with chain IDs). The description reinforces the chain coverage but does not add new parameter-specific information, so schema carries the burden.

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 uses a specific verb ('Get aggregated token holdings with USD values') and clearly identifies the resource (wallet address). It also distinguishes from siblings by noting that native ETH balance is included, making a subsequent get_eth_balance call redundant.

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 description explicitly warns against calling get_eth_balance separately, which is a clear exclusion. It also implies this tool is for broad portfolio views across supported chains, though it doesn't enumerate all alternatives.

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