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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is known. The description adds useful behavioral context beyond that: the tool is free, the e-CPF signature is valid for only 10 minutes, and it specifies exactly what data is returned (live credentials and CPF checks). No contradictions with annotations.

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?

Two sentences with no wasted words, and the cost/scope information is front-loaded. The first sentence is a bit awkward and fragmented, but the overall structure is efficient.

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?

With no output schema, the description should explain the return values more precisely. It vaguely states 'every live credential ... and every CPF check', but does not describe the response structure, format, or pagination, leaving meaningful gaps for a data-fetching tool.

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 defines both parameters fully, including the exact signed_text format and the CMS/PKCS#7 base64 DER encoding of ecpf_signature. The description adds only the 10-minute validity period for the signature, which is minor and somewhat ambiguously worded.

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 names a resource ('every live credential behind your e-CPF and every CPF check') and distinguishes the tool from the company variant with 'person only', but it never states a clear verb or action. It reads as a fragment describing output content rather than what the tool does, and the term 'credential' is used where the tool name says 'agents', creating ambiguity.

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?

It gives context ('Free, person only') that implicitly separates this from kya_company_agents, but it never explicitly says when to use this tool versus other siblings like kya_verify or kya_prove. No when-not conditions or alternatives are named.

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