Get Username

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

Annotations already indicate readOnlyHint=true, so the description adds value by noting usernames are 'non-secret scalar output' and that exact IDs are safest. It does not mention error handling or behavior on multiple matches, but annotations cover the read-only nature.

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 concise sentences: first establishes purpose, second adds a crucial usage hint. No unnecessary words, front-loaded for quick understanding.

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 the single parameter, annotations, and output schema, the description is nearly complete. Missing explicit mention of return format or what happens on multiple matches, but output schema likely covers return type. Slight gap in handling ambiguity.

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 already describes 'term' as search term or item ID. The description adds safety context about exact IDs being safest for ambiguous names, enhancing understanding beyond the schema definition.

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 it retrieves a login username using a search term, referencing 'bw get username' for familiarity. It distinguishes from sibling tools like keychain_get_password or keychain_get_item by specifying the exact resource and behavior.

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?

Provides guidance on using exact item IDs for ambiguous names, implying when to prefer precision over search. However, it does not explicitly state when to use this tool versus alternatives like keychain_search_items or keychain_get_item.

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