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

With no annotations, the description carries the full burden and does well: it discloses the history boundary ('History starts at tracking_since'), the warning triggered by an earlier since, and the important caveat that count 0 plus a warning does not mean nothing changed. It does not cover pagination, rate limits, or what the response body looks like beyond checked_at, so it is not complete.

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?

Three short sentences, each doing distinct work: what changes are tracked, how to poll, and the history/count-0 pitfall. Front-loaded with the purpose and zero filler.

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 two-parameter read tool with no output schema and no annotations, the description covers purpose, polling protocol, and the main correctness trap. The only real gap is the unmentioned `provider` filter and a lack of any return-shape hint beyond checked_at.

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 50%: `since` is documented in the schema and the description enriches it meaningfully (clamped by tracking_since, earlier values yield a warning). The `provider` parameter is undocumented in both schema and description, so the description only partially compensates for the coverage gap. Baseline 3 is appropriate.

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?

A specific verb ('List') plus a precisely scoped resource ('tracked AI model records whose status, deprecation/shutdown date, replacement or source changed'), with an explicit time qualifier. That enumeration makes it clearly distinct in kind from get_provider or get_shutdown_date, though no sibling is named. It falls short of 5 only because the differentiation must be inferred rather than stated.

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?

Gives a concrete operating pattern: 'Poll this to stay current: on later calls pass the previous response's checked_at.' That is real when-to-use guidance tied to a follow-up call. It stops short of explicit exclusions (e.g., when to prefer list_upcoming or search_models instead), so 4 rather than 5.

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