PEX MCP Server

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

With no annotations provided, the description carries the full burden of behavioral disclosure, yet only implies read-only access through the verb 'Get'. It fails to describe what constitutes an 'advanced' rule, what data structure is returned, or whether the card must be active/valid.

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 single sentence is efficient and front-loaded with the action and target resource. However, given the crowded namespace with 60+ similar siblings, extreme brevity becomes a liability rather than virtue.

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?

Inadequate for an API surface with numerous similar spending-rule tools and no output schema. The description should clarify the relationship between card-specific advanced rules and ruleset-level configurations, and hint at return value structure.

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?

With 100% schema coverage (the 'id' parameter is fully documented as 'Card account ID'), the schema does the heavy lifting. The description adds no parameter-specific context (e.g., expected ID format, where to obtain this ID), warranting the baseline score of 3.

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 states a clear verb ('Get') and resource ('advanced spending rules'), but adds minimal semantic value beyond the tool name itself. It fails to differentiate from similar siblings like 'pex_get_card_spend_rules' (basic vs advanced) or ruleset-related endpoints, leaving ambiguity about which tool to select.

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?

No guidance provided on when to use this tool versus alternatives such as 'pex_get_card_spend_rules' or the various 'ruleset' endpoints. No prerequisites, filtering guidance, or exclusion criteria are mentioned.

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