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

With no annotations, the description discloses key behaviors: returns pricing table when no plan given, creates checkout URL when plan given, works on expired databases, and restores them. This is sufficient transparency.

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 informative but slightly lengthy. However, it is front-loaded with the main behavior and organized with conditionals. Every sentence contributes useful information.

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 2 parameters, no output schema, and no annotations, the description covers the workflow: input behavior, conditions, and follow-up action. It does not detail the return format of the pricing table, but it is adequate for use.

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 50%, but the description adds value by explaining the conditional behavior based on the 'plan' parameter (absent vs. present). It also describes the 'db' parameter as the URL from creation. This goes beyond the schema alone.

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's function: extend database lifetime via payment. It distinguishes between without plan (pricing table) and with plan (checkout URL) and covers expired databases. This differentiates it from siblings like create_database or database_status.

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 tells when to use (to extend a database) and provides a crucial guideline: never buy without explicit user approval. It also instructs to call database_status after payment. However, it does not compare to alternatives like pro_checkout or pro_attach_database.

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