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

Goes well beyond the annotations: discloses that a pending/unknown hash returns 404 and is uncharged, that failed calls are free, and explains why readOnlyHint is false (each call is charged). This pricing/error/billing context is exactly the kind of behavior annotations cannot convey.

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 the purpose, then usage/alternative, then input format, then billing and error semantics. Dense but every clause (404 uncharged, free failed calls, read-only rationale) carries actionable information for an agent.

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 no output schema, the description fully carries the burden of describing return fields (status, gas, fees, logs, contract created), input format, error behavior, and cost model. Nothing needed to invoke or interpret a call 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?

Schema coverage is 100%, so the baseline is 3, but the description reinforces the input contract ('0x-prefixed 64-hex hash') and supplies a full concrete example hash. The worked example is real added value over the schema's generic format note.

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 ('Get the receipt of a mined Polygon PoS transaction') and enumerates exactly what the receipt contains: status, gas used, effective gas price, fee in POL, log count, contract created. It explicitly distinguishes itself from the sibling polygon_tx by naming what that tool covers instead.

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 the triggering scenario ('Use to confirm a payment or call went through') and routes the agent to the alternative with its selection condition ('for sender, value and calldata use polygon_tx'). When-to-use and when-to-use-something-else are both explicit.

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