get_user

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

Annotations already declare readOnlyHint=true, idempotentHint=true and destructiveHint=false, so the safety profile is covered. The description adds the not-found contract ('Returns null if no user has that email'), which is meaningful behavior an agent must handle and which is not expressed in the 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?

Two sentences, both front-loaded and informative — the lookup scope first, then the not-found behavior. No filler and nothing repeated from the schema or annotations.

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 one-parameter lookup with an output schema, the description covers identity, matching semantics, and not-found behavior, which is nearly everything needed. Minor gaps are permissions or error behavior, which are less critical for a read-only lookup.

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 0%, so the description needs to carry parameter meaning. It does the single most important thing: it specifies exact-match semantics for the email parameter, telling the agent it cannot pass partial or fuzzy values.

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?

Specific verb ('look up') plus a precise resource ('one Twingate user') and a scoping constraint ('by exact email'). The singular 'one user by email' implicitly separates it from the sibling list_users tool, which returns many users.

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 tool implies its use case ('look up one user by exact email'), but there is no explicit statement about when to use it versus list_users or get_user_access. The 'exact email' constraint hints that partial-match cases need a different tool, but that is inference, not guidance.

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