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

No annotations are provided, so the description carries the full behavioral burden. "Return" implies a read-only operation and the default replacement behavior is disclosed, but details such as permissions, error behavior, and what the diff contains are absent.

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 short sentences, front-loaded with the core action and followed by the key default behavior. It is efficient, though the extreme brevity leaves important gaps that additional wording could fill.

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 two parameters with zero schema description coverage, no annotations, and no output schema, the description is under-specified. It does not explain the required from_model_id, the return shape, failure cases, or how the diff is scoped.

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 0%, so the description must compensate. It usefully explains that omitting to_model_id defaults to the official replacement, but it does not describe the required from_model_id or clarify the format and meaning of either model identifier.

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 specific verb and resource: "Return the migration diff for a model." This is enough to distinguish it from siblings like check_model, scan_text, and upcoming_shutdowns, though it does not explicitly name or contrast those alternatives.

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 sentence "Defaults to the official replacement" clarifies the optional to_model_id behavior but does not explain when to use this tool versus check_model or other siblings. There are no explicit usage conditions, prerequisites, or exclusions.

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