id

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

States 'Read-only, no side effects' which aligns with readOnlyHint annotation. Adds that output is JSON with full identity. No contradiction.

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?

Three sentences, front-loaded with purpose. Slight redundancy ('Returns JSON with full user identity' repeats earlier info) but efficient overall.

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?

Covers purpose, usage boundaries, parameter behavior, and alternatives. No gaps given tool's simplicity and available annotations.

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?

Parameter 'raw' already fully described in schema (100% coverage). Description repeats schema wording without adding new semantics.

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?

Clearly states 'Return user identity information' with specific fields (UID, GID, username, group memberships). Distinctly separates from siblings 'whoami' and 'groups' by specifying scope.

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 says when to use (comprehensive inspection, access control auditing) and when not (quick username check, group listing). Names alternatives ('whoami', 'groups').

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