MCP YAML API

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

The description adds minimal behavioral context beyond annotations. Annotations indicate this is a write operation (readOnlyHint: false), non-destructive, and open-world (openWorldHint: true), but the description doesn't elaborate on implications like potential side effects (e.g., sending welcome emails) or constraints (e.g., rate limits). It doesn't contradict annotations, but offers little extra insight into how the tool behaves in practice.

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 extremely concise with a single sentence: 'Create a new user.' It's front-loaded and wastes no words, making it easy to parse quickly. Every word contributes directly to the core purpose without unnecessary elaboration.

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?

Given the tool's complexity as a write operation with no output schema and minimal annotations, the description is insufficient. It doesn't cover what happens upon creation (e.g., returns a user ID, sends notifications), error conditions, or how it interacts with sibling tools. For a user creation tool in a system with multiple user-related operations, more context is needed to guide effective 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 0% schema description coverage, the schema provides no parameter descriptions, but the description doesn't compensate by explaining parameters. However, since there are only 2 parameters (name and email), and their purpose is somewhat self-evident from the tool's name, the baseline is higher. The description doesn't add semantic details, but the simplicity of parameters keeps the score from being lower.

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 states the action ('Create') and resource ('new user'), which is clear but basic. It doesn't distinguish this tool from sibling tools like 'replaceUser' or 'updateUser', which also modify user data. The purpose is understandable but lacks specificity about what makes this creation operation unique.

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 siblings like 'replaceUser' and 'updateUser' available, it doesn't clarify that this is for initial creation of a user, not modification of existing ones. There's no mention of prerequisites, such as needing admin permissions or when this operation is appropriate.

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