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

Annotations already provide readOnlyHint=true and destructiveHint=false, and the description reinforces this with 'FREE DISCOVERY' and 'before payment', making the non-destructive nature clear. However, the description does not go beyond the annotations to disclose additional behavioral traits such as whether the returned 'next actions' include actionable steps, the exact structure of policy information, or any rate limits. It adds minimal context beyond what annotations and the semantic summary already provide.

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 single, information-dense sentence that front-loads the key constraint ('FREE DISCOVERY') and lists the specific categories of information returned. It avoids unnecessary words and every part contributes meaning. The additional usage/constraints fields in the definition are redundant but not part of the core description, and the core description itself is exceptionally concise and well-structured.

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 has no parameters, no output schema, and is a read-only discovery endpoint, the description covers the essential information: what it returns (identity, commerce model, payment rails, policy, next actions) and when to use it (before payment). It lacks a bit of detail on the exact format of 'next actions' or what 'commerce model' entails, but for a zero-parameter free discovery tool, the description is sufficiently complete for an agent to call it correctly.

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?

The tool has zero parameters, so there are no parameter descriptions to cover. The baseline for zero-parameter tools is 4, and the description appropriately focuses on the output rather than inputs. It does not need to explain any parameter semantics because there are none, and the schema confirms this with 100% coverage (empty properties).

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 ('Returns') and resource ('provider identity, commerce model, payment rails, policy, and next actions') and clearly indicates this is a discovery tool to be used before payment. It differentiates itself from siblings like 'check_requirements' and 'list_offerings' by focusing on provider-level discovery rather than requirements checking or simple listing, though it doesn't explicitly name alternatives.

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 and usage context explicitly state 'before payment' and 'Free to use, no payment required, read-only', which tells the agent when to use it: when considering a provider and needing to learn about their business model, payment methods, and next actions. It doesn't explicitly say when not to use it or name alternatives, but the context signal strongly implies the appropriate usage scenario.

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