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

Annotations already declare readOnly/destructive/openWorld, but the description adds meaningful context beyond them: the 404-and-uncharged behavior for pending hashes, and the pricing/credit model that explains why idempotentHint=false ('each call is charged, so repeats are not free'). It does not describe response shape in detail, but the enumerated fields largely cover that.

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 what the tool does and what it returns, followed by the disambiguation and the failure mode. The pricing/credits sentence is longer than strictly needed and partially duplicates the idempotency note, keeping it just short of a 5.

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 carries the return-value burden and does so by enumerating the receipt fields. Combined with the 404 behavior, pricing model, and the sibling pointer, an agent has everything needed to call this correctly.

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 description is not obligated to explain the single hash parameter. It nonetheless adds a concrete worked example hash and reiterates the 0x-prefixed 64-hex format, which marginally improves invocation accuracy over the schema alone.

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+resource ('Transaction receipt on Celo') and enumerates exactly what the result contains — status, gas used, effective gas price, fee in CELO, log count, contract created. It explicitly contrasts with the sibling celo_tx, so the agent can pick between them without opening either 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 a concrete use case ('confirm a payment or call went through') and names the alternative tool plus the condition that selects it ('for sender, value and calldata use celo_tx'). Also states the failure path: pending/unknown hash returns 404 and is uncharged.

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