List Users

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 meaningful behavioral detail beyond annotations: every upstream page is fetched server-side, the result is the complete roster, and there is no further pagination to request. This is exactly the kind of hidden behavior an agent needs to know before invoking.

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 sentences, each earning its place: the first defines the operation and output, the second gives the primary use case, and the third resolves the pagination question. The most decision-relevant facts are front-loaded, and there is no redundant restating of the tool name or schema fields.

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 one-parameter, read-only list tool with no output schema, this description is complete. It states what is returned, that only active users are included, that the result is exhaustive, and that no further paging is needed. The account_slug parameter is fully covered by the schema, and the annotations handle the mutation/safety context.

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 account_slug parameter is already well documented in the schema, including an example and cross-references to fizzy_get_identity and fizzy_get_accounts. The description does not add additional parameter-level meaning, but it does not need to because the schema fully carries that burden. Baseline of 3 is appropriate.

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 uses a specific verb and resource: 'Get all active users in an account,' followed by the concrete return fields (IDs, names, emails, access levels). It also clarifies scope via 'complete roster' and 'no page parameter,' which distinguishes it from any paginated or single-user endpoint like fizzy_get_user. The purpose is immediately unambiguous.

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 explicitly states when to use the tool: 'Use this to discover available users for card assignments.' This gives clear situational context. It does not explicitly name an alternative for retrieving a single user or state when not to use this tool, so it falls short of full exclusion guidance.

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