plan_get_cheapest_plan

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

No annotations are provided, so the description carries the full burden of explaining behavior. It indicates a read/return operation but does not disclose what 'cheapest' compares (price metric, billing period), what 'available' means, or what happens when no plan matches the filter. This leaves key selection-criteria behavior unexplained.

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 extremely lean: a one-line purpose followed by tight Args and Returns sections. There is no redundant text, and the core purpose is front-loaded.

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-optional-parameter read tool with an output schema, the description is minimally usable. However, in the context of a large family of plan-related tools, it does not explain valid plan_type values or distinguish 'cheapest available' from availability/region-based plan queries, leaving an agent to guess.

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 0%, so the description must compensate for the bare input schema. It adds only 'Optional plan type filter,' which restates the parameter's optionality without defining valid plan_type values, format, casing, or how filtering is applied. This is insufficient for a parameter that is central to the tool's behavior.

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 specific verb and resource: 'Get the cheapest available plan.' This is clearly distinct from list/get/search siblings in principle, and the optional plan_type filter adds scope. However, it does not explicitly draw the boundary against plan_compare_plans or plan_get_plan_by_type_and_spec.

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?

There is no guidance about when to use this tool versus the many sibling plan tools such as plan_search_plans_by_specs, plan_get_plan_by_type_and_spec, or plan_get_plans_by_region_availability. The only implied context is the tool's name and first line; no exclusions, prerequisites, or alternative routing are given.

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