dnstwist_scan

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

With no annotations, the description carries the burden and discloses the passive nature ('only sends DNS queries, no HTTP requests') and the permutation logic. It also explains registered_only and check_mx semantics, but omits potential rate limits or error behavior.

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 well-organized with distinct sections for purpose, args, returns, and notes. Every sentence provides useful information; the Args list is necessary because the schema lacks descriptions, and there is no repetition or fluff.

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 tool's complexity, the description covers purpose, all parameters, return values, and key constraints like allowed_hosts and passive operation. With an output schema present, this is sufficient for an agent to decide on and invoke the tool 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 description explicitly explains all five parameters with meanings and defaults, fully compensating for the 0% schema description coverage. The domain example and registered_only/default values add meaning beyond the raw schema.

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 detects typosquatting and phishing domains by generating permutations and checking registration with dnstwist. This specific verb+resource+method distinguishes it from sibling DNS tools like dns_enumerate or whois_lookup.

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 usage for typosquatting investigation and includes prerequisites (allowed_hosts) and behavioral context (passive OSINT). However, it does not explicitly mention alternatives or state when not to use this tool, stopping short of full exclusions.

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