logname

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

Annotations already mark as readOnly. Description adds that it is unaffected by su/sudo and returns JSON, which are important behavioral details beyond annotations.

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?

Concise: two core sentences plus usage guidance and alternatives. No fluff, front-loaded with purpose.

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 1 optional parameter and no output schema, description covers purpose, behavior, output format, and usage context completely.

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 coverage is 100% with description for 'raw' parameter. Description does not add extra parameter info beyond 'returns JSON', which indirectly relates but is not needed.

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 it returns the original login name, unaffected by su/sudo, and distinguishes itself from 'whoami' (effective user ID) and 'id'.

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?

Explicitly states when to use: to determine original session identity bypassing privilege escalation, and when not: for effective user ID, use 'whoami'. Also references 'id'.

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