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

Annotations already establish readOnlyHint=true, destructiveHint=false and openWorldHint=true, so safety is covered. The description adds genuinely useful behavior the annotations lack: a 20-person batch cap, and that a missing person is silently omitted rather than causing an error, plus that the full record, tags and segment data are returned.

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?

Three short sentences, front-loaded with the lookup key and the batch limit, then the return shape. No filler and every clause carries information an agent needs.

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 adequately covers inputs, batch size, return contents and the subtle missing-person behavior. Minor gaps remain: no error/permission behavior for malformed identifiers and no ordering guarantee for results.

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% and the nested item schema already documents id, email and userId with formats and length bounds, so the baseline is 3. The description restates the 'at least one identifier' and max-20 constraints without adding syntax or format detail 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?

States a specific verb and resource ('Look up people (contacts)') and enumerates the three accepted identifier types. The batch-lookup-by-identifier framing distinguishes it from listing siblings such as encharge_list_segment_people, which enumerate rather than resolve identifiers.

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 implies the usage context — you must have an email, userId or Encharge id in hand, and you can batch up to 20. However, it never names an alternative (e.g. encharge_upsert_person or encharge_list_segment_people) or states when not to use it, so the guidance is only implied.

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