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

Goes well past the readOnlyHint/openWorldHint annotations: it discloses that the sample binary is never downloaded (metadata only), states the exact price ($0.002 USDC per successful call via x402 across Base/Solana/Arc), and clarifies failed calls are free. That billing and no-download information is exactly the non-obvious behavior an agent needs before calling a paid external lookup.

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 core action and followed by three short, high-value clauses (metadata-only, pricing, non-billing on failure). The long enumeration of returned fields is somewhat wasteful since an output schema already exists, making it the main trimming candidate.

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?

Return values are covered by the output schema, and the description supplies the remaining decision-relevant facts: hash input format, metadata-only behavior, and payment model. Nothing an agent needs before invoking a paid, external threat-intel lookup 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% and the schema already documents hash formats and the legacy sha256 alias, so the description's mention of SHA-256/SHA-1/MD5 adds little. It also never mentions the sha256 alias parameter, so it does not compensate beyond the schema. Baseline 3 applies.

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 (looks up) and resource (file hash in abuse.ch MalwareBazaar) and enumerates exactly what comes back (hashes, file name, signature, first/last seen, tags, code-signing). Naming the source dataset separates it from the other malware/threat-intel siblings such as security_urlhaus_malware and security_threatfox_iocs.

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?

The framing 'whether the sample is known' plus the required file hash makes the use case (hash triage / sample identification) obvious. It does not, however, explicitly exclude or route to alternatives like urlhaus or threatfox when the hash is unknown.

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