Register a new user via shared-secret registration

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It does reveal the authentication mechanism (shared secret) and clarifies that the admin token is not used. However, it does not describe what happens after creation (e.g., whether the user is immediately active, whether errors occur if the username already exists, or what the response format is). This is a notable gap for a create 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?

The description is two concise sentences, with the primary action front-loaded in the first sentence. The second sentence adds necessary context about configuration and authentication. No filler words or redundancy; every word contributes.

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?

Given that there is no output schema and no annotations, the description should explain return values and potential errors, but it doesn't. It provides essential context about the registration flow and prerequisites, which is valuable, but it omits information about what a successful or failed invocation yields. For a relatively simple create-user tool, this partial completeness is acceptable but not thorough.

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?

The schema coverage is only 50% (username and admin have descriptions; password and displayname do not), and the description adds no parameter-specific guidance. It doesn't explain the purpose of 'admin', 'displayname', or the semantics of 'password' beyond their basic types. The description could have elaborated on these parameters but instead focuses solely on the authentication flow.

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 states a specific action: 'Create a new local account' using Dendrite's shared-secret registration flow. It clearly identifies the resource (a user account) and the method, distinguishing it from sibling tools like create_registration_token which manage tokens, not 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 description provides clear context for when to use this tool: it requires the shared-secret registration flow and DENDRITE_REGISTRATION_SHARED_SECRET to be configured. It also notes that it does not use the admin bearer token, implying it should be used when shared-secret auth is appropriate. However, it doesn't explicitly enumerate exclusions or name alternative tools for user management.

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