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

Annotations already declare readOnlyHint=true, destructiveHint=false and idempotentHint=false, yet the description still adds real context: the result spans confirmed and pending transactions, malformed addresses fail with 400 and are uncharged, pricing is $0.01/call with 25 free, and failed calls are free. The warning that 'each call is charged, so repeats are not free' usefully reinforces the non-idempotent hint with a practical consequence.

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?

Front-loaded with purpose and usage, then error, example, and pricing in descending priority. It is dense and mostly earns its words, though the pricing/credits sentence is longer than the calling decision strictly requires.

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?

For a one-parameter read tool with no output schema, the description covers what the value means (confirmed vs. including pending), the error contract, and the cost model. Nothing an agent needs in order to call it correctly or interpret the result is missing.

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?

There is a single parameter with 100% schema coverage ('0x address'), so the schema already carries the semantics and a baseline 3 applies. The description adds an example address that clarifies the expected 0x hex format, but nothing about checksum casing or chain-specific address handling.

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 the transaction count (nonce) of a 0x address on Sei') and scopes it precisely to confirmed plus pending. It names the sibling it is not ('for its balance use sei_balance'), so an agent can distinguish it from the many chain-prefixed *_nonce and sei_* siblings without opening a 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?

Gives two concrete when-to-use cases: building the next transaction, and determining whether an address has ever sent anything. It also explicitly routes the balance case to sei_balance, which is the only plausible confusion point in this tool family.

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