MCP YAML API

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

Annotations provide key behavioral hints: readOnlyHint=false (mutation), openWorldHint=true (flexible inputs), idempotentHint=false (non-repeatable), destructiveHint=false (non-destructive). The description adds minimal context beyond this—it implies a full replacement of user data but doesn't specify effects (e.g., overwrites all fields, may require permissions) or constraints (e.g., rate limits). With annotations covering safety and idempotency, the description adds some value but lacks operational details.

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 a single, efficient sentence ('Replace an existing user.') that is front-loaded with the core action. There is no wasted verbiage or redundancy, making it highly concise and well-structured for quick comprehension.

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 (mutation with 3 parameters, no output schema, and annotations covering basic hints), the description is incomplete. It lacks details on parameter usage, behavioral implications (e.g., what 'replace' means operationally), and output expectations. For a tool that modifies user data, more context is needed to ensure correct invocation, especially with 0% schema coverage and no output schema.

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 0%, so parameters 'id', 'name', and 'email' are undocumented in the schema. The description provides no parameter information—it doesn't explain what 'id' refers to (e.g., user identifier), whether 'name' and 'email' are new values, or if other fields are affected. This fails to compensate for the schema gap, leaving parameters ambiguous.

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 'Replace an existing user' clearly states the verb ('Replace') and resource ('user'), making the tool's purpose immediately understandable. It distinguishes from siblings like 'createUser' (new user) and 'updateUser' (partial modifications), though it doesn't explicitly contrast with 'deleteUser' (removal). The description is specific but could be slightly more precise about what 'replace' entails versus 'update'.

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. It doesn't mention prerequisites (e.g., needing an existing user ID), exclusions (e.g., not for new users), or comparisons to siblings like 'updateUser' (for partial changes) or 'deleteUser' (for removal). Without this context, an agent might struggle to choose correctly between similar tools.

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