check_fast_flux

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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is clear. The description adds behavioral context by explaining the multi-round query process and what it compares (IP answer sets and TTLs), which goes beyond the annotations. It does not mention rate limits or caching behavior, but the force_refresh parameter hints at caching.

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 main purpose and then explaining the method. It is concise and avoids fluff, though the second sentence somewhat repeats the first. No wasted words, but could be slightly tighter.

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 moderate complexity (4 params, output schema present), the description covers the core behavior and purpose. The output schema exists, so return values are documented elsewhere. The description could mention caching behavior or rate limits, but the annotations and schema cover most needs. It is complete enough for an agent to select 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?

Schema description coverage is 100%, so the schema already documents all four parameters. The description adds context about the overall purpose but does not add new meaning to individual parameters beyond what the schema provides. The description mentions 'multiple rounds' which aligns with the 'rounds' parameter, but the schema already explains that.

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 fast-flux DNS behavior by performing multiple rounds of A/AAAA queries and checking for rapid IP rotation and TTL changes. It explicitly names the resource (domain) and the specific behavior (fast-flux), distinguishing it from sibling DNS check tools like check_mx or check_spf.

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 explains the method (multiple query rounds, comparing IP sets and TTLs) and the purpose (identifying botnet/malicious infrastructure), which implies when to use it. However, it does not explicitly state when not to use it or mention alternatives, though the sibling list shows many other DNS checks that could be alternatives.

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