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

Goes well beyond the annotations: it discloses the 404-without-charge behavior for pending/unknown hashes, per-call pricing ($0.01 via x402 USDC or card key), a 25-call free tier, free failed calls, and that repeats are billed again. That last point is consistent with idempotentHint=false and explains it rather than merely restating it.

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 returns and who it competes with, then the input format and example, then billing. It is dense and slightly overloaded with pricing terms, but nearly every clause carries information an agent needs before spending money on a call.

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?

There is no output schema, so the description correctly enumerates the fields returned, plus error behavior and cost. Minor gap: it says 'number of event logs' but doesn't indicate whether the logs themselves are included, which matters for an agent deciding between avax_receipt and avax_logs.

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 documents the 0x-prefixed 64-hex format, so the description's baseline is 3. It adds a concrete worked example hash plus the semantics of a bad/unresolved hash (404), which is genuine value beyond the schema, though the format detail is partly duplicated.

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 Avalanche'), names the underlying RPC (eth_getTransactionReceipt), and enumerates the returned facts (status, gas used, gas price, fee in AVAX, log count, created contract). It also explicitly differentiates itself from the sibling avax_tx, so an 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 the use case ('confirm a payment or call went through') and names the exact alternative for the complementary job ('for sender, value and calldata use avax_tx'). The failure condition (pending/unknown hash → 404, uncharged) is also stated, which is the kind of routing detail agents need.

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