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

While annotations already declare readOnlyHint and idempotentHint, the description adds valuable context beyond them: data is 'human-verified', 'updated weekly', and includes the 'date the pricing was last verified'. It also enumerates the exact return fields (monthly price, included minutes, setup fees, overage rates, free trial), giving the agent a clear picture of the output.

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 concise and well-structured: it states the core function, lists return fields, provides usage triggers, and mentions coverage/frequency in four efficient sentences. No filler or redundancy.

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 a simple one-parameter tool with no output schema, the description covers the essential context: what it does, what it returns, when to use it, and data freshness. Annotations cover safety, so nothing critical 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?

Schema coverage is 100% for the single 'service' parameter, with clear examples in the schema itself. The description provides examples too, but does not add new semantic details beyond what the schema already offers, so the baseline 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 opens with a specific verb ('Get') and resource ('current, human-verified pricing for a specific answering service'), directly distinguishing it from siblings like compare_answering_services. It also cites concrete service examples, making the tool's scope unmistakable.

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?

Provides explicit trigger phrases ('how much does X cost', 'X pricing', 'is X worth it') that signal when to use this tool. However, 'or asks for alternatives to a named service' is slightly ambiguous because this tool returns pricing for one specific service, not alternative recommendations—the sibling compare tool might be more appropriate for that use case.

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