Get user details

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

Annotations already indicate this is a read-only, idempotent, non-destructive operation. The description adds no additional behavioral context (e.g., what kind of details are returned, authentication requirements, or rate limits). With annotations present, the bar is lower, but the description provides zero added value beyond what the annotations already convey.

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 sentence, front-loaded with the verb and resource, making it easy to scan. It is concise, though it could be slightly expanded with more context without losing conciseness. It earns its place but lacks some helpful detail.

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 simple getter with one parameter and annotations, the description covers the basic purpose. However, without an output schema, the description should hint at what 'details' means (e.g., user info like name, email). It is adequate but not fully complete for an agent that needs to know what to expect in return.

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?

The input schema has one required parameter 'userId' with a clear description 'User ID', covering 100% of parameter documentation. The description does not add further semantic detail (e.g., format or constraints) beyond the schema, but baseline is met given full schema coverage.

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 'Get', the resource 'user', and specifies 'details of a specific user'. This distinguishes it from sibling tools like 'arcane_user_list' (lists all users) and 'arcane_user_update' (modifies user). The purpose is immediately clear and precise.

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 implies usage when you need details for a single user, but it does not explicitly state when not to use it or mention alternatives (e.g., using 'arcane_user_list' if you need multiple users). However, given the context of sibling tool names, the purpose is clear enough for basic differentiation.

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