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

Annotations already declare readOnlyHint false, destructiveHint false, and idempotentHint true. The description adds substantial behavioral context beyond that: it never returns assignment values (privacy guarantee), costs 500 micro-dollar service credits per successful call, requires existing credits and a private Authorization header, and clarifies that a new requestId is a new billable operation. This is rich, non-obvious information that annotations do not cover. No contradiction with annotations.

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 a few sentences, front-loaded with the core purpose, then cost, prerequisites, and recovery. Every sentence adds essential information: the purpose, the privacy guarantee, the cost, the prerequisite step, and the billing behavior. There is no fluff or repetition.

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?

Given the tool's complexity (paid, requires preparation, has an output schema), the description covers the essential operational aspects: purpose, cost, prerequisites, recovery, and a key behavioral guarantee (no value returns). The output schema presumably defines the return format, so that gap is acceptable. However, it does not specify what 'compare' returns (e.g., a diff list, a match/mismatch flag), which an agent might want to know before calling. This slight omission keeps it from being a 5.

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 67% (requestId and maxPriceMicroUsd have descriptions; the nested input object does not). The description gives the overall purpose of comparing template and actual, which helps infer what 'input' contains, but it does not elaborate on the format or semantics of the template and actual strings beyond that. It adds some value over the schema but does not fully compensate for the missing input property descriptions.

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 action ('Compare environment-variable names') on a specific resource (against a template) and immediately clarifies it never returns assignment values, which distinguishes it from any tool that might expose secrets. It also mentions the paid nature, adding uniqueness. This is clear and differentiates it from siblings like agents_config_audit or security_secret_scan.

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 instructs to first use agent_utilities_prepare, lists prerequisites (existing credits and a private Authorization header), and explains recovery behavior (reuse prepared arguments, new requestId is a new billable operation). This gives clear when-to-use and step-by-step operational guidance, including a caution about billing. It does not explicitly name alternatives but effectively routes the user through the required preparation step.

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