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

Annotations already provide readOnlyHint=true, so no safety contradiction exists. The description adds significant behavioral detail beyond the annotation by listing the exact benefit items and limits the tool reports, as well as that it operates from the plan's own Benefit Schedule. This goes beyond the minimum and clarifies the tool's output scope, though it does not discuss rate limits, errors, or other less-visible behavior.

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 dense but purposeful, front-loading the core purpose ('What one plan actually pays, item by item') before enumerating specifics. The two sentences each carry information—the first defines scope and contents, the second gives usage examples. It could be slightly tighter, but it earns a high score for efficiency.

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?

With a single well-documented parameter, readOnlyHint annotations, an output schema present, and explicit usage guidance, the description is complete for an agent to invoke the tool correctly. Nothing necessary for selection or calling is missing.

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%; the only parameter (cert) is clearly described as a VHIS certification number from an earlier result with an example format. The description adds no further meaning to cert, so the baseline 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 states a specific verb+resource: it reports what one plan actually pays, item by item from its Benefit Schedule, and enumerates covered categories (room/board, hospital, surgeon, imaging, cancer, psychiatric, limits, territory, extras). It also includes explicit example queries ('is surgery covered in full'), making the tool's purpose unmistakable and clearly distinct from siblings like compare_plans or find_plans.

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 gives clear usage contexts: 'Use it for "what does this cover", "is surgery covered in full", "does it include outpatient".' This tells an agent when to invoke the tool. It does not explicitly name alternatives or say when not to use it, so it earns 4 rather than 5.

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