Rebillia MCP Server

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

No annotations are provided, so the description carries full burden. It mentions 'POST /subscriptions/from-product-rateplan' which implies a write operation, but doesn't disclose important behavioral traits like: whether this is idempotent, what permissions are needed, what happens on failure, or what the response contains. For a creation tool with zero annotation coverage, this is insufficient.

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 concise with two sentences: one stating the purpose and endpoint, another listing required parameters. No wasted words, though it could be slightly more structured by separating the endpoint from the purpose statement.

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 creation tool with 5 required parameters and no annotations or output schema, the description is incomplete. It doesn't explain what a subscription is in this context, what happens after creation, error conditions, or return values. The agent would struggle to use this effectively without trial and error.

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 description coverage is 100%, so the schema already documents all 5 parameters with their types and basic descriptions. The description lists the required parameters but adds no additional semantic context beyond what's in the schema (like format examples beyond effectiveStartDate's YYYY-MM-DD, or relationships between parameters).

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 ('Create a subscription') and source ('from a product rate plan'), providing specific verb+resource. However, it doesn't explicitly differentiate from sibling tools like 'add_subscription_rate_plan' or 'create_product_rate_plan', which could cause confusion about when to use each.

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 'add_subscription_rate_plan' and 'create_product_rate_plan', the agent receives no help distinguishing appropriate use cases. Only the required parameters are listed, not contextual guidance.

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