bl_check_malware

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

With no annotations, the description carries the transparency burden. It clearly indicates a read-only check ('Check'), lists the specific sources queried, and states the return value (whether malware association was found and the source). This is sufficient for a simple lookup tool, though it doesn't detail potential caveats like rate limits or real-time vs. cached data.

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 two sentences, front-loaded with the action and resource, and contains no filler. Every phrase adds value: the specific blocklist names and the return value are both essential for understanding the tool.

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?

For a tool with one parameter and no output schema, the description is complete: it states what is checked, against which sources, and what is returned. It could potentially detail the exact response format, but for this simple lookup, the description provides enough context for an agent to use it 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% and the schema already fully describes the single parameter 'domain' with an example. The description does not add additional parameter-level semantics beyond what the schema provides, so the baseline score 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 clearly specifies the action ('Check a domain'), the resource (malware-specific blocklists), and names concrete sources (abuse.ch URLhaus, Spamhaus DBL, SURBL malware category). This distinguishes it from sibling tools like bl_check_phishing or bl_check_dnsbl by focusing on malware-specific categories.

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 description provides clear context: use when you need to check a domain specifically against malware blocklists. It doesn't explicitly mention alternatives, but the specificity of 'malware-specific' and the listed sources imply the appropriate use case, differentiating it from general DNSBL or phishing checks.

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