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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so the safety profile is covered. The description adds real behavioral context beyond that: the PARSE→DECISION verification flow and the exact return payload (validity, format, trust score, issues).

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, front-loaded with the action and the accepted formats before the pipeline detail; the return summary is appropriately last. The parenthetical format list is dense but earns its place as scope definition.

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 single-input verification tool with no output schema, the description covers input scope, processing pipeline, and return fields (validity, format, trust score, issues), which is enough for correct invocation. Only the sibling-routing guidance 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 a single parameter at 100% schema coverage, the schema already defines 'credential' as a JSON string or JWT. The description adds value by enumerating the accepted credential types (ATC v3, JWT/OAuth, W3C VC, MCP Card, A2A, EAT-AI, ZTA, SPIFFE SVID, X.509), which tells the agent which inputs are in scope.

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 (Verify) and resource (AI agent credential) and enumerates supported credential formats, so the agent knows exactly what class of input this handles. It also clarifies the pipeline scope by distinguishing the UTA 12-stage flow from Sentinel's skill-audit stages, though it never names the closest siblings (translate_credential, check_revocation) to draw the boundary.

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?

Usage is implied: the enumerated credential formats signal when this tool applies, and the Sentinel contrast scopes the pipeline. However, there is no explicit when-to-use versus when-not-to-use guidance and no routing to sibling tools such as check_revocation or translate_credential.

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