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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It fully discloses the nature of the returned data and the version omission behavior. It does not mention potential side effects or prerequisites, but the tool is clearly a read-only query and the disclosed details are sufficient for safe invocation.

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?

The description is two sentences with no filler. The first sentence densely covers the purpose and full content list, while the second gives a crucial usage directive. It is front-loaded with the verb and object, making it scannable and efficient.

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?

Given that an output schema exists, the return format is already handled. The description thoroughly enumerates the scope of breaking changes, mentions the official source URL, and provides a behavioral caveat about version omission. This is sufficient for an agent to decide when and how to invoke the tool.

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 coverage is 0%, so the description must compensate. It clarifies that 'version' can be omitted to retrieve all tracked versions, and it contextualizes 'package' as the subject of an upgrade. It does not specify formatting requirements for 'package,' but that is trivially inferable from the tool name and use case.

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?

The description states a clear and specific action: 'Get breaking changes for a package upgrade,' and enumerates the exact content (removed APIs, replacements, reasons, changed defaults, behavior changes, dependencies, source URL, codemod commands). This makes it unmistakably distinct from sibling tools like list_packages and check_upgrade_safety.

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 explicitly instructs to 'Use this instead of relying on training data, which may predate the release,' providing a clear when-to-use directive. It also explains the optional version behavior with 'Omit version to get every tracked version.' However, it does not directly contrast the sibling tools, so some context for choosing among alternatives is missing.

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