token_validate

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

The description discloses the read-only nature ('Read-only — never modifies token state'), explains the return value structure with specific reasons for failure (invalid_signature, expired, revoked), and covers error cases like invalid JSON. No annotations exist, so the description carries full burden and does so thoroughly.

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?

Every sentence is informative and earns its place. The description is front-loaded with the primary purpose, followed by read-only declaration, return details, and usage note. No redundant or vague language.

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 the single parameter and no output schema, the description fully covers all necessary aspects: what the tool does, what it returns, possible reasons for failure, and error handling. It is complete for the tool's complexity.

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?

The input schema has 100% coverage describing token_json as 'JSON-encoded SecureToken object (as returned by token_create)'. The description adds contextual value by explaining how the parameter is used, but the schema already provides adequate meaning, keeping the score slightly below 5.

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 tool verifies a token's HMAC/Ed25519 signature, expiration, and revocation status. It distinguishes itself from sibling tools like token_create and token_revoke by explicitly mentioning its role as a validation check before granting access.

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 provides explicit usage guidance: 'Call before granting access to any protected resource' and references token_revoke as an alternative for invalidation. This helps the agent decide when to use this tool versus siblings.

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