Generate Username

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

The description confirms the tool never mutates the vault (consistent with readOnlyHint annotation) and explains the reveal/redaction behavior in detail, adding value beyond annotations.

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 clearly states purpose, second adds essential behavioral notes. No redundant information.

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 output schema present and good annotations, the description covers core purpose and reveal behavior, though it lacks examples or ordering hints. Adequate for the tool's complexity.

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 100% so the baseline is 3. The description does not add significant parameter details beyond listing the generation strategies, which are already covered by the type enum.

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 a username like the Bitwarden generator, listing specific strategies (random word, plus-addressed email, etc.), and distinguishes from sibling tools that handle other keychain operations.

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 on using reveal=true to return values and mentions NOREVEAL/KEYCHAIN_NOREVEAL for forced redaction, but does not explicitly exclude when not to use or compare with related tools like keychain_get_username.

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