Identity post prelogin

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

Annotations already declare readOnlyHint=false, destructiveHint=false and openWorldHint=true, so the description does not need to re-declare safety. It adds value by naming the exact fields returned and the precondition step, but does not mention that this endpoint is typically unauthenticated, what happens for unknown emails, or that the POST is read-only in effect.

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?

One front-loaded sentence naming the action, the returned values, the input key, and the timing. 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?

With no output schema, the description usefully enumerates the returned KDF fields, which is the most important missing context. The remaining gap is parameter placement (email in json_body vs. form/params), which matters given three undocumented parameters.

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% across three generic parameters (form, params, json_body), and the description only hints that an email is involved without saying which parameter carries it. For a tool where all parameters are opaque and undocumented, the description should have specified where the email goes; it adds almost nothing 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?

States a specific verb and resource: retrieve a user's KDF type/iterations/memory/parallelism by email, framed as a pre-login step. That is far more informative than the tautological name/title, though it does not distinguish itself from near-name siblings such as vaultwarden_accounts_post_prelogin or vaultwarden_prelogin_password.

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?

'before attempting login' implies the usage context and ordering relative to a login attempt. There is no explicit statement of when not to use it, no mention of the sibling prelogin/KDF variants, and no note about whether the email must already exist.

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