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

Annotations already cover readOnly/idempotent/non-destructive, so the description is freed to add real content: it itemizes exactly what is returned, including whether the change is still undoable and its expiry window, and it explicitly discloses that the undo token is NOT returned here. That negative disclosure is genuinely useful context that no annotation or schema carries.

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 sentences, front-loaded with the verb and the returned payload, with no filler. The second clause is slightly run-on ("receipt_url, the receipt in Royally where a person can undo it"), but every part conveys a distinct fact.

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?

There is no output schema, so the description must carry the return-shape burden, and it does by naming each returned component plus the deliberate omission of the undo token. It stops short of describing error behavior for an unknown or expired receipt_id, a minor gap for a single-param read.

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% and the single parameter is self-documenting ("receipt id returned in the original mutation envelope"), so the schema does the heavy lifting. The description adds no format, sourcing, or failure-mode detail about receipt_id beyond what is already structured — baseline 3 applies.

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 ("Fetch a full receipt for a prior change") and enumerates the payload: the receipt, the execution it records, undo status/expiry, and receipt_url. It is unambiguous on its own, but never names a sibling (e.g. fleet__list_recent_receipts or fleet__get_execution), so an agent must infer the boundary itself.

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 by "for a prior change" and the schema note that receipt_id comes from the original mutation envelope. The description never says when to prefer this over list_recent_receipts (to discover ids) or get_execution (to inspect the execution alone), leaving the routing decision to inference.

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