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

Annotations already declare readOnlyHint=true, indicating no side effects. The description adds valuable behavioral details: it returns SIGNATURE_MISMATCH if the card is tampered, and it is verification-only. It does not contradict annotations. The description could be enhanced by noting any prerequisites (e.g., registry access) but is sufficient given the read-only nature.

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 three sentences with no unnecessary words. Key information is front-loaded: purpose, error condition, and use case. Every sentence adds value.

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 verification tool with 2 parameters and no output schema, the description is complete. It covers the purpose, behavior, parameter semantics (including optional fallback), and use case. It does not explicitly state the success return value, but the error case (SIGNATURE_MISMATCH) is described, which is sufficient for understanding.

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?

Both parameters (did, cardPayload) have descriptions in the schema, achieving 100% coverage. The description adds semantic value beyond the schema: it explains that if cardPayload is omitted, the tool uses the registry-stored version for self-verification. This extra context justifies a score above the baseline of 3.

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 verb (판정합니다 - determines), the resource (페르소나 명함 - persona card), and the specific purpose (validating signature to detect tampering). It differentiates from sibling tools: get_persona_card retrieves cards, query_persona_decision queries decisions, sync_persona_card syncs cards, while this tool is exclusively for verification.

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 explicitly says when to use the tool: '에이전트 사칭 여부를 확인할 때 사용하세요' (use when checking for agent impersonation). It also notes it is verification-only and performs no actions. However, it does not explicitly mention when not to use it or provide direct alternatives, though the sibling context provides implicit differentiation.

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