list_customers

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

With no annotations, the description carries the full burden and does well: it discloses pagination, sorting options, environment filtering, and MCP-specific page_size limits. It does not mention authorization, rate limits, or data freshness, but for a read-only listing tool the behavioral surface is well covered.

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?

The description is well organized with clear sections for query parameters, response fields, and use cases. It is somewhat long because of the response-field list, but since there is no output schema, those fields are valuable rather than redundant.

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?

The description covers parameters, response fields, scope, and practical use cases, which is especially helpful given the absence of an output schema. It is not fully exhaustive (e.g., no error handling or auth prerequisites), but it gives an agent enough context to select and invoke the tool effectively.

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 meaningful value with sort_by examples ('-total_cost', '-number_of_requests'), environment enumeration, and the important MCP max page_size distinction (50 vs 1000). This goes beyond the schema's basic parameter documentation.

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 opens with 'List customers/users with pagination and sorting,' a specific verb and resource with clear scope. It clarifies that only customers who have made API requests are included, and 'get_customer_detail' among siblings implies a related but distinct single-record operation.

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 provides concrete use cases: 'identify top users by cost, most active users, or find specific customers.' It does not explicitly state when not to use this tool or point to get_customer_detail as an alternative, but the context is clear enough for typical list-vs-detail decisions.

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