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

With no annotations, the description is the sole source of behavioral info. It states that results are limited to upcoming shutdowns within N days, that migration targets are returned, and that the service is free. It does not mention data source, refresh cadence, rate limits, or output shape, but these are less critical for a simple no-side-effect lookup.

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 short and readable, front-loading the core action and scope. The leading 'FREE.' is arguably noise for an invocation decision, but not misleading; 'Default 90 days' repeats the schema.

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 one-optional-parameter tool, the description explains what is returned, which providers are covered, and the default window. Because there is no output schema, a description of the exact response format would be useful if this were more complex, but the current coverage is adequate.

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 description need not expand parameters much. It reinforces that N is a day window and the default is 90, but adds no semantics beyond the schema's own 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?

The description clearly identifies the tool's function: listing AI models scheduled for shutdown within a configurable window across four providers, with migration targets included. This distinguishes it from siblings like is_model_live (current availability) and get_model_lifecycle_all (broader lifecycle data).

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 use case is implied by the wording: call when you need upcoming deprecations and migration targets. However, it never explicitly says when to prefer this over model_lifecycle/get_model_lifecycle_all, and offers no exclusions or prerequisites.

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