Rebillia MCP Server

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

With no annotations provided, the description carries full burden but offers minimal behavioral context. It mentions the HTTP method (POST) and lists parameters, but doesn't disclose important behavioral traits like whether this is a mutating operation (implied by 'Add'), what permissions are needed, rate limits, error conditions, or what happens on success. The description doesn't contradict annotations (none exist), but provides inadequate behavioral 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 appropriately sized but poorly structured. It starts with the purpose, then includes implementation details (POST endpoint), then lists parameters in a dense paragraph. While information-dense, it could be better organized with clearer separation between purpose, usage context, and parameter guidance. Some sentences are overly long and combine multiple concepts.

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 complex mutation tool with 17 parameters, no annotations, and no output schema, the description is insufficient. It doesn't explain what happens after successful execution, error handling, or the business context of adding a charge to a subscription rate plan. The description focuses primarily on parameter listing without providing the complete operational context needed for effective tool 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?

With 100% schema description coverage, the baseline is 3. The description adds some value by grouping parameters (e.g., noting that billingPeriodAlignment and specificBillingPeriod are required when chargeType is recurring), but mostly repeats what's already documented in the schema. It doesn't provide additional context about parameter interactions or business logic beyond what the schema already specifies.

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 action ('Add a rate plan charge to a subscription rate plan') and specifies the resource involved. It distinguishes from sibling tools like 'create_product_rate_plan_charge' by focusing on subscription-level operations rather than product-level, though this distinction could be more explicit.

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 no guidance on when to use this tool versus alternatives. With many sibling tools like 'create_product_rate_plan_charge' and 'update_subscription_rate_plan_charge', there's no indication of when this specific 'add' operation is appropriate versus creating or updating related entities.

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