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

With readOnlyHint=true already declaring safety, the description adds value by enumerating the returned content: codes, item counts, fees, domain list, and weights. This is consistent with annotations and gives the agent useful expectations about result richness without contradicting anything.

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 concise sentences, front-loading the specific content delivered and then providing a clear call-to-action. Every word earns its place; no redundancy or filler.

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 simple parameterless list tool with annotations covering the read-only nature and a closed world, the description fully explains the return payload and the intended invocation order. Nothing needed for correct selection or successful invocation 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?

With zero parameters, there is no parameter semantics to add. The baseline of 4 applies because the description has no need or opportunity to clarify parameters.

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 lists Claude certifications with exam codes, item counts, fees, and domain lists/weights. It also explicitly frames the role as the entry point for obtaining valid exam slugs, which distinguishes it from siblings like check_answer or get_practice_question.

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 phrase 'Call this first to get valid exam slugs' gives explicit timing guidance and explains why this tool should precede others. It does not explicitly list alternative tools or when not to use it, but the sibling context and the clear sequencing instruction are sufficient.

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