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

Adds behavior beyond annotations: nonce includes confirmed and pending transactions, malformed addresses return 400 uncharged, and pricing/free-call details are stated. It also explicitly explains why readOnlyHint=false despite being read/compute only, resolving the annotation's apparent tension.

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?

The description is front-loaded and every sentence carries operational information. It is slightly dense with pricing and example details for a one-parameter tool, but not wasteful.

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?

Covers purpose, usage, error handling, payment model, and annotation rationale for a simple read/compute tool. With no output schema, it could be more explicit about the returned nonce format or whether confirmed and pending counts are separate, but the gap is minor.

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% and the schema already defines the single address parameter. The description adds an example 0x address and validation behavior (malformed address rejected with 400), which gives extra value but no additional format syntax.

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: reads the transaction count (nonce) of a 0x address on Polygon PoS. It distinguishes its scope by naming polygon_balance as the tool for balance, so an agent can route correctly among chain-specific siblings.

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 concrete use cases: build the next transaction or determine whether an address has ever sent anything. It also names the alternative for balance (polygon_balance), leaving no inference needed about that sibling.

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