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

No output schema exists, and the description compensates by disclosing the shape of the returned record (lines, reasons, deltas, VAT, delta gross, status history, running value). Annotations mark readOnlyHint=false, which is in tension with the read-style "Return" phrasing, but the description makes no explicit side-effect claim, so this is not a contradiction — just an unexplained annotation.

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 tight sentences, front-loaded with the payload summary and closing with the sibling hand-off. No filler, though "or client" is a small ambiguity that could have been dropped or sharpened.

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?

With a single required parameter, no output schema, and only annotations for safety signalling, the description does the heavy lifting by listing the returned fields and the discovery path. It is complete enough to call correctly; only the ambiguous key types leave a gap.

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 100%, so the parameter is already documented as an id (e.g. CO-2026-0001) or a unique title. The description's "by CO number or client" adds a lookup mode not present in the schema and slightly muddies the accepted key types rather than clarifying them.

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 ("Return one change order in full") and enumerates the scope of what is returned — added/removed/changed lines, reasons, deltas, VAT, status history. It is immediately distinguishable from change_order_list, which is named as the discovery tool.

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?

Explicit routing is provided: "change_order_list finds the id" tells the agent to use the sibling for discovery and this tool for the full record. It stops short of stating exclusions or prerequisites (e.g. what happens when the lookup key is ambiguous), so it falls just short of a 5.

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