auth_create_user

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

With no annotations, the description carries the full burden, and it does disclose the important non-obvious trait that this targets an emulator with synthetic data only. It does not state what happens on duplicate uid/email, whether the created account is returned (e.g. uid), or that all fields are optional, leaving meaningful behavioral gaps for a write operation.

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?

A single sentence, front-loaded with the action and scope, with the safety constraint placed at the end. Every clause earns its place and there is no filler.

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 an 8-parameter creation tool with no annotations and no output schema, the description covers purpose and safety but omits the return value, the fact that nothing is required, and how conflicts are handled. Adequate but with clear gaps for a mutation tool.

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 the baseline is 3. The description confirms which identity facets can be supplied (email/password, phone number, display name) and adds the synthetic-data constraint, but adds no format, validation, or interaction semantics beyond the schema.

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 names a specific verb and resource ('Create an Auth emulator account') and scopes it to a synthetic/emulator context, which clearly separates it from read/delete siblings like auth_get_user or auth_delete_user. What keeps it from a 5 is that no sibling is named explicitly and the set of optional identity fields is listed loosely (

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?

There is one real usage constraint embedded — '(never real credentials)' — which tells the agent this is for test/emulator fixtures only. But there is no explicit statement of when to use this versus auth_mint_token, auth_set_claims, or how to proceed if a user already exists, so usage must be inferred from the tool name.

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