Look up users

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

Annotations already establish the read-only, idempotent, non-destructive safety profile, so the description's additional note about requiring BUGZILLA_API_KEY on bugzilla.mozilla.org adds valuable operational context. It also clarifies fuzzy matching semantics with the ':dholbert' example, going beyond the schema. No contradictions with 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 tight sentences: the first states the operation and accepted identifiers, the second adds a critical auth caveat. No filler, and the fuzzy-match example is placed where it helps most.

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?

For a simple read-only user lookup with three optional, fully documented parameters, the description covers the lookup modes and the only significant environmental constraint (API key). It doesn't describe the return value shape, but the absence of an output schema and the low complexity keep this from being a serious gap.

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 description coverage is 100%, so the baseline is 3; the schema already documents ids, match, and names with their types and matching behavior. The description adds a nickname example but does not materially expand parameter semantics beyond what the schema provides.

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 opens with a specific verb and resource ('Look up Bugzilla users') and enumerates the three identification modes: login/email, numeric ID, and fuzzy name/nickname match, including a concrete example. This clearly distinguishes the tool from bug-centric siblings like search_bugs and get_bug.

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 establishes the tool's purpose and the authentication prerequisite for bugzilla.mozilla.org, providing clear context for when it can be invoked. It doesn't explicitly name alternatives or exclusion cases, but the resource-specific wording makes the use case unambiguous among the sibling tools.

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