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

Annotations already declare readOnlyHint=true, and the description reinforces this with a read-oriented verb. It adds meaningful context beyond the annotation by stating 'No credentials needed,' clarifying authentication expectations and reducing the perceived need for setup.

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?

Two short sentences with no filler. The core purpose and content scope are front-loaded, and the credential note is a useful standalone addition.

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 parameterless read-only tool, the description covers purpose, scope, and authentication expectations. Since there is no output schema, the enumerated content list effectively communicates what the agent can expect to learn from the manifest.

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 is nothing for the description to explain. The baseline for a no-parameter tool is 4, and the description adequately conveys that no inputs are required.

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?

States the specific verb 'Read' with the resource 'commerce manifest' and enumerates the contained information: protocol, endpoints, authentication scheme, payment instrument, and limits. This clearly differentiates it from sibling action tools like create_order and start_payment.

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 context for when to use this tool: to obtain protocol, endpoint, authentication, and payment-limit details before taking action. It adds the practical note that no credentials are needed, which helps the agent decide it can be called without auth setup, though it does not explicitly contrast with alternatives.

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