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

Annotations cover the safety profile (readOnlyHint, openWorldHint), and the description usefully adds a cost model not present in structured fields: 15 credits per user, minimum 15, waived on bulk. It stops short of noting error handling or partial-failure behavior for invalid ids.

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 short sentences, front-loaded with the core operation and followed by the pricing caveat. No filler, and every clause carries actionable 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?

For a single-parameter read-only batch tool with no output schema, the definition covers purpose, cost, and batch scope adequately. The only minor gap is how return values are shaped (e.g., mapping ids to profiles) and what happens on unknown ids.

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% and documents userIds as a comma-separated string, so the baseline is 3. The description adds that the ids are numeric and that many can be supplied at once, which meaningfully reinforces the format beyond the schema.

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 states a specific verb (Resolve), resource (numeric user ids), and output (full profiles), with the batch scope made explicit ('in one call'). It implicitly contrasts with individual lookup, which maps to sibling user_info, but never names that sibling directly.

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?

It gives a clear selection signal — use this for bulk resolution because it is 'far cheaper per user than looking them up individually' — which steers the agent away from per-id calls. There is no explicit when-not condition or named alternative, but the context is clear.

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