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

Annotations already set readOnlyHint=true, and the '(READ ONLY)' text merely restates that rather than adding new behavioral context. The endpoint notation (GET /payment_orders/{id}) is a small extra, but nothing is said about error behavior for missing ids, auth requirements, or expandable sub-resources. For a simple read this is acceptable but thin.

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?

One short sentence, front-loaded with the verb and resource, with the endpoint trailing. The parenthetical '(READ ONLY)' is redundant with the annotations and slightly wastes space, keeping it just short of a 5.

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 one-parameter read tool with no output schema and no nested objects, the description is sufficient to invoke correctly: the agent knows it fetches one payment order given an id. Nothing essential is missing, though it does not hint at what fields the returned object contains.

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 schema documents the single 'id' parameter at 100% coverage, so the schema already carries the semantics. The description's 'by id' adds no format or sourcing detail beyond what is already there, which matches the baseline 3 for a fully covered single-parameter schema.

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 a specific verb and resource ('Get a single payment order by id'), and the word 'single' implicitly separates it from the list_payment_orders sibling. It does not name that sibling explicitly, so the differentiation is inferential rather than stated.

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?

Usage is only implied: an agent can infer this is the fetch-one-by-id path when the id is already known, versus list_payment_orders for enumeration. No explicit when-to-use, when-not-to-use, or named alternative is provided.

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