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

Beyond the readOnlyHint and openWorldHint annotations, the description discloses important behavioral traits: the call is read-only and sends nothing, very new signatures may return 404 without charge, successful calls cost $0.002 in USDC via x402, and failed calls are not charged. This is rich, actionable transparency.

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 with what the tool returns, then efficiently adds read-only status, 404 behavior, and pricing. Every sentence adds useful information with no filler.

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?

Given the existence of an output schema and annotations covering read-only/open-world behavior, the description is complete enough. It covers the resource, the required parameter, return contents, failure behavior, and payment details, leaving no critical gap for correct invocation.

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 one required parameter, and the schema already documents it fully as a base58 transaction signature with 100% schema description coverage. The description reinforces that the lookup is by signature, but adds no format or syntax detail beyond the schema, so the baseline of 3 is appropriate.

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?

The description names the specific resource (a Solana transaction), the required lookup key (by signature), and the exact fields returned (status, time, fee in SOL/USD, signers, balance changes, token changes, programs invoked). This clearly distinguishes it from sibling tools such as evm_tx, btc_tx, solana_account, and solana_wallet without needing to open any 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?

Usage is implied: call this when you have a Solana transaction signature. The 404 note for very new signatures gives useful context, but the description does not explicitly say when to prefer this over alternatives like solana_account or solana_wallet, nor does it state exclusions.

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