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

Annotations already declare readOnlyHint=false, idempotentHint=false and destructiveHint=false, so the safety profile is covered. The description adds real value beyond that: the environment-dependent 409 conflict condition and the fact that email must be new. It does not mention side effects such as whether the teammate is immediately active or what the response contains, but with annotations and an output schema present that gap is modest.

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 tight sentences, zero filler. The core action is front-loaded and the precondition is stated before the exclusionary alias note, so the most decision-relevant information comes first.

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 create tool with annotations covering idempotency and side-effect profile, a full schema, and an output schema, the description covers the remaining decision-critical unknown — the directory-integration conflict — and clearly separates alias management. Nothing needed to invoke it correctly is missing.

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 description coverage is 100%, so email, context and smart_fields are fully documented in the schema itself (including smart-field failure semantics and null clearing). The description restates the email + smart-field composition without adding syntax or constraints beyond what the schema already provides, so the baseline of 3 applies.

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?

States a specific verb and resource ("Create a new teammate") and immediately scopes the input shape ("from a primary email plus optional smart-field values"), which separates it from list_teammates, update_teammate and delete_teammate at a glance.

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?

Gives an explicit precondition with a concrete failure mode: create is only usable when the workspace manages its own team list, and a directory integration (Google, Microsoft, Zoho Mail) yields a 409 conflict. It also excludes a related concern — email aliases are handled elsewhere — so the agent knows this tool is not the route for aliases.

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