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

Annotations only say the operation is read-only and open-world, so the description carries the burden of behavioral detail. It explains that data comes from 'Inclusify's live configuration rather than remembered', tells the agent not to quote a price from memory, and discloses that invoice-managed sites cannot self-serve upgrade. This goes well beyond the structured annotations without contradicting them.

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 fairly lengthy but front-loaded with immediate use cases, then product details, then a key behavioral warning about not quoting prices from memory. Every section contributes distinct value, though it could be tightened slightly without losing meaning.

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 tool with no output schema, the description is remarkably complete: it specifies the full return set (every plan, price, visitor allowance, audited-page allowance, feature list), explains that current plan usage is also returned, and reveals the billing-ownership nuance. An agent has enough information to use this tool correctly in a wide range of plan-related questions.

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 schema has one parameter and 100% schema description coverage, so the schema fully documents the parameter. The tool description does not discuss the parameter, which is fine given the high coverage baseline, but it adds no additional meaning about how to populate or format it.

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 identifies this tool as the resource for any question about plans, pricing, limits, and upgrading, with concrete examples like 'what plan are we on' and 'how many pages do we get'. It also distinguishes itself from generic plan tools by emphasizing it returns live configuration data and current usage allowances, making its scope unmistakable.

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 gives explicit trigger conditions: 'Use this for any question about plans, pricing, limits or upgrading' and 'Also use it after any tool refuses on a plan gate.' It does not explicitly name sibling alternatives or state when not to use it, but the examples and the post-refusal use case provide clear contextual routing.

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