get_user_info

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

With no annotations provided, the description carries the full burden. It explicitly states 'Read-only' and discloses that a passwd read failure is non-fatal, which is valuable safety-related context. It also mentions the case-insensitive substring behavior for the search parameter. It does not detail every edge case, but for a simple read-only query tool, this is strong transparency.

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 composed of four short, purposeful sentences. Each sentence adds distinct value: what it lists, search behavior, read-only/failure mode, and intended use. There is no redundant fluff, and the most critical information is front-loaded.

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 read-only tool with one optional parameter and an output schema present, the description covers all necessary aspects: purpose, behavior, failure handling, and usage intent. It does not need to explain return structure since the output schema exists. The description is complete for the tool's complexity.

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 schema already describes the search parameter as 'optional username filter (case-insensitive substring match)', and the description repeats this almost verbatim ('search does a case-insensitive substring match'). Since schema coverage is 100% and the description adds no new meaning beyond the schema, the baseline score of 3 is appropriate.

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 a specific action ('Lists system users') and identifies the exact data sources ('/etc/passwd and /etc/group') with the fields returned (username, UID, GID, home, shell, supplementary groups). This clearly distinguishes it from sibling tools like get_logged_in_users or get_user_automation, which target different aspects of user information.

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 explicit usage context: 'Use for account inventory and membership checks.' This tells the agent when to select this tool. However, it does not mention alternatives or cases where it should not be used (e.g., when you only need currently logged-in users), so it stops short of a full 5.

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