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

With no annotations provided, the description carries the full burden and does well: it discloses that the tool holds NO funds, cannot provision, and returns a provision field with three ways to get the server. This gives the agent a clear behavioral model without relying on the schema.

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?

Three sentences with no wasted words. The description front-loads the action ('get the exact payment'), then adds key constraints ('holds NO funds', 'cannot provision'), and ends with an actionable instruction ('Read it and act on it'). Every sentence earns its place.

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?

Despite lacking an output schema, the description mentions the provision field and explicitly instructs the agent to 'read it and act on it.' It covers the tool's purpose, limitations, and next step, making it fairly complete for a 2-parameter info retrieval tool. Minor omissions like response format details or expiration behavior prevent a higher score.

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% with both plan and days already described. The description adds workflow context by tying the parameters to 'RENT a plan for N days,' but this is not significantly more semantic than the schema's own descriptions, so a baseline 3 is appropriate.

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 uses a specific verb ('get the exact payment') and clearly identifies the resource (payment to RENT a plan for N days, USDC via x402, card availability). It distinguishes itself from siblings like get_server and list_plans by emphasizing it handles payment requirements and explicitly does not provision.

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 frames the tool as 'Step 2' in a workflow, implying when to use it relative to other steps. It also states this hosted server cannot provision and returns everything needed to pay elsewhere, which tells the agent not to expect provisioning here. However, it does not explicitly name an alternative tool for provisioning.

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