users_resolve

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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is covered. The description adds the exclusivity rule, which is genuine behavioral context, but says nothing about the error/failure mode when the constraint is violated or what resolution yields. With annotations carrying the safety burden, this is a fair 3.

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 compact sentence with the operation front-loaded and the constraint stated immediately after. No filler or redundancy.

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 read-only lookup with no output schema, the description should clarify what 'resolve' returns and the failure behavior when the exactly-one rule is broken. It covers the input contract adequately but leaves the outcome and edge-case handling unstated.

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 0% and the schema itself enforces neither required nor exactly-one, so the description carries the important mutual-exclusivity semantics that the schema omits. It names all three parameters but adds no type/format distinction (numeric id vs string shortUuid/username) beyond their names.

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?

Specific verb 'Resolve' plus resource 'user' with the three accepted lookup keys, which is clearer than the bare name. However, it does not distinguish itself from siblings users_get, users_get_by_username, and users_get_by_short_uuid, so the agent can't tell from the description alone why it would choose this aggregator over a per-key getter.

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 'EXACTLY ONE of' clause gives the calling constraint, implicitly telling the agent this is a single-key lookup. But there is no guidance on when to prefer this over users_get or the per-key siblings, and no mention of what happens if zero or multiple keys are supplied.

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