Generate Username

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

Annotations already indicate readOnlyHint=true. The description adds details beyond annotations: 'This never mutates the vault' and explains the reveal parameter behavior with NOREVEAL/KEYCHAIN_NOREVEAL forcing redaction, which is valuable context.

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: first defines purpose and strategies, second adds critical behavioral nuance. No wasted words. Front-loaded effectively.

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?

Covers purpose, safety (read-only), and reveal behavior. With an output schema present, return format is not needed. Could mention prerequisites or edge cases (e.g., email required for plus-addressed) but overall sufficient.

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?

Input schema has 100% description coverage for all 6 parameters, so description adds limited extra meaning. It mentions the strategies but schema already defines them via enum. The reveal parameter note is the main addition, but baseline is 3.

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 clearly states the tool generates usernames using specific strategies (random word, plus-addressed email, etc.). It explicitly says 'Generate a username' and lists the strategies, distinguishing it from sibling tools like keychain_generate (passwords) and keychain_get_username (retrieval).

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 implies this tool is for generating new usernames, but lacks explicit when-to-use or when-not-to-use guidance or alternatives. It only says 'like the Bitwarden generator,' which is vague.

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