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

readOnlyHint=true already establishes a safe read operation. The description adds no behavioral context beyond that: no auth requirements, rate limits, pagination behavior, or return format are disclosed; 'FUB: GET /v1/users' largely restates the annotation's implication.

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 fragments with no filler: the first defines scope and purpose, the second gives the API route. Information is front-loaded and every element earns its place.

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 list tool with a fully documented 6-parameter schema and a readOnlyHint annotation, the description covers what the tool returns and why to call it. It leaves out return shape and pagination behavior, but limit/offset are already documented in the schema.

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 even though the description does not document any of the six parameters. The mention of 'agents, brokers, lenders' loosely maps to the role filter, but it does not add syntax or meaning beyond the schema's own role description.

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 identifies the resource (users in the account, i.e., agents, brokers, lenders) and the endpoint GET /v1/users, and the title supplies the verb 'List.' It clearly explains the returned entity and its role for assigning people, tasks, and deals, but it does not differentiate from other list or retrieval siblings such as fub_search_people or fub_get_identity.

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 states a concrete use case—obtaining IDs to assign people, tasks, and deals—which tells an agent when to reach for this tool. It does not name alternatives or exclusions (e.g., when to use fub_search_people or fub_get_identity instead), so it stops short of explicit routing guidance.

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