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

With readOnlyHint=true already covering the safety profile, the description still adds real behavioral context: Trash-stage people are excluded unless includeTrash is true, and the default projection omits fields unless `fields` is passed. It adds moderate value beyond 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?

Five short sentences, each carrying a distinct behavioral fact (AND logic, partial matching, default sort, trash exclusion, projection) with no repetition of the schema. Front-loaded and waste-free.

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 25-parameter, zero-required search tool with no output schema and only a readOnly annotation, the description covers the non-obvious behavior (trash exclusion, default projection, sort default) well. It could say slightly more about paging (e.g. that `next` is preferred over `offset`), but the schema already carries that.

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% so the baseline is 3, but the description adds cross-parameter rules the schema cannot express: AND-combination of criteria, partial-match behavior for name filters, and how to widen the returned field set via `fields` / 'allFields'. That is genuine added meaning over the per-field descriptions.

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?

Opens with a specific verb+resource ('Search contacts and leads'), which cleanly separates it from single-record siblings like fub_get_person and fub_check_duplicate_person. The trailing 'FUB: GET /v1/people' anchors it to a concrete endpoint.

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?

Gives operative search semantics (criteria combine with AND, name filters are partial, newest-first default) and points to fub_list_stages for valid stage names. It never states the exclusion condition against alternatives, e.g. 'use fub_get_person when you already have an id', so it stops short of a 5.

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