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

Annotations already declare read-only/idempotent, and the description goes well beyond them: it discloses the default sort order, the paging model, the required credential, and a concrete failure mode (403 for sandbox keys from self-registration until the workspace is claimed). That 403 behavior is exactly the kind of runtime trait an agent needs and cannot get from structured fields.

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?

Four short sentences, each carrying distinct information: purpose, filtering, paging, safety, then prerequisites. Nothing is repeated and the most decision-relevant facts come first.

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 zero-required-parameter list tool with a fully described schema and read-only annotations, everything an agent needs to call it correctly is present: ordering, paging, filter semantics, auth requirement, and the workspace-claim failure case.

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 coverage is 100%, so the baseline is 3, but the description adds the joint paging semantics ('page with limit and offset') and clarifies that customer_id narrows the result to one customer's orders rather than being a required filter. That is modest but real value above the schema text.

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?

Opens with a precise verb+resource ('List the orders in your workspace') and adds scope details: default ordering (newest first) and an optional customer filter. It never names a sibling such as get_order or list_order_lines, so an agent must infer the boundary from the schema, but the listing purpose itself is unambiguous.

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?

Gives clear operating context: use it for a whole-workspace listing, add customer_id for a single customer, and page with limit/offset. It also states prerequisites (credential, claimed workspace) up front, which steers the agent before invocation, though it does not explicitly exclude or point to alternative tools.

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