Rebillia MCP Server

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It mentions the HTTP method (PUT) and lists optional parameters, but fails to describe critical behaviors like whether this is a mutation (implied by 'Update'), what permissions are required, whether changes are reversible, or what happens to unspecified fields. For a mutation tool with zero annotation coverage, this leaves significant gaps.

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 efficiently structured in two sentences: one stating the core action and HTTP endpoint, another listing optional parameters. There's no unnecessary verbiage, though the parameter list could be more readable with bullet points or grouping.

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 mutation tool with 9 parameters, no annotations, and no output schema, the description is inadequate. It lacks behavioral context (permissions, side effects), usage guidance relative to siblings, and any information about return values or error conditions. The parameter listing doesn't compensate for these broader gaps.

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 9 parameters thoroughly. The description adds minimal value by listing optional parameters in a comma-separated format, but doesn't provide additional context like format examples (e.g., date format for effectiveStartDate) or relationships between parameters beyond what the schema offers.

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 verb ('Update') and resource ('a subscription'), making the purpose immediately understandable. It doesn't explicitly distinguish from sibling tools like 'update_subscription_status' or 'update_subscription_rate_plan', but the core action is well-defined.

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?

No guidance is provided about when to use this tool versus alternatives like 'update_subscription_status' or 'update_subscription_rate_plan'. The description lists parameters but offers no context about prerequisites, appropriate scenarios, or exclusions.

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