bl_check_surbl

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

No annotations are provided, so the description must fully disclose behavior. It states that the tool returns 'listed/not listed per list with category', clearly conveying output behavior. It does not mention potential timeouts or detailed response structure, but for a simple read-only check, this is adequate.

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 a single, front-loaded sentence that states the action, scope, and return value without unnecessary words. It is appropriately concise and well-structured.

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?

This is a simple tool with one parameter and no output schema. The description explains what it does and what it returns at a high level. It lacks detailed category enumeration, but given the simplicity, it is sufficiently complete for an agent to invoke 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?

The input schema has 100% coverage for the single 'domain' parameter, with a description that mirrors the tool description. The description adds no additional semantics beyond the schema, 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 states the tool checks a domain against domain-based blocklists, naming specific lists (SURBL, Spamhaus DBL, URIBL). The verb 'Check' and resource 'domain' are specific, and it distinguishes from sibling bl_check_dnsbl by specifying 'domain-based' rather than IP-based blocklists.

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 implies the tool is for checking domains (not IPs) against domain-based blocklists, providing clear context. However, it does not explicitly mention alternatives or when not to use it, such as for IP-based checks, though sibling tools like bl_check_dnsbl exist.

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