Verify an agent's credential

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

Annotations already declare readOnlyHint and openWorldHint, so safety is covered. The description adds genuinely new context: it is free, it performs a live issuer lookup, and it enumerates return contents including the status lifecycle (active, suspended, revoked, expired) and history. It does not mention error/not-found behavior or rate limits, but for a read-only lookup that is a minor omission.

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?

Front-loads the key qualifier 'Free.' and packs return contents, input options and usage trigger into a tight block. The rhetorical opener 'Who answers for this AI agent?' adds a little flavor at slight cost to density, but nothing is truly wasteful.

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 correctly takes on the burden of describing return values (principal, mandate, status, history) and does so. Both optional parameters are fully documented in the schema, so the only real gap is behavior on missing/invalid credentials or no-match results.

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%, so the baseline is 3. The description adds real semantic value beyond the schema by clarifying the either/or relationship ('Give credential_id, or the agent key') and disclosing that supplying an agent key returns its active credentials (plural), which the schema does not state.

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?

States a specific verb and resource (looks up the agent's KYA Brasil credential at the issuer) and enumerates what comes back: principal, mandate, live status, history. It implicitly distinguishes itself from siblings like kya_verify_credential_offline (issuer lookup vs offline) and kya_verify_paid ('Free.'), but never names an alternative explicitly.

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 a clear triggering condition: 'Use it before trusting an order, payment or signature that comes from an agent.' That is strong positive guidance, but there are no exclusions or named alternatives telling the agent when to reach for a different verify-family sibling instead.

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