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

Annotations already declare readOnly, idempotent, non-destructive, and closed-world behavior, so the safety profile is covered. The description adds real value beyond that by disclosing data provenance — the 'expected to retire' value is an estimate from Brickset, labelled as such — and by flagging that LEGO.com sale status is a separate signal. It does not say how unknown or malformed set numbers are handled.

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?

One compact sentence-fragment that front-loads the outcome enumeration and closes with the input example. The status list is dense but every clause adds distinct information; nothing is redundant.

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 single-parameter read-only lookup with no output schema, enumerating the possible statuses effectively documents the return values, which is the key missing piece. The remaining gap is error/unknown-set behavior and the absence of sibling routing, both minor for a tool this simple.

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 carry the parameter meaning, and it does: the sole input is identified as the set number, with concrete format examples ('75192' or '10497-1') that reveal both plain and variant-suffixed notation. That is more guidance than the bare string schema offers, though it stops short of stating accepted input variants exhaustively.

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 names the resource (a LEGO set's retirement status) and enumerates the possible outcomes — on sale, expected to retire, retired, no longer made — so an agent can tell exactly what it gets back. It does not explicitly differentiate itself from siblings like get_item or search_catalogue, keeping it short of a 5.

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 implied: query with a known set number when you need retirement lifecycle status. There is no explicit when-to-use/when-not-to-use statement and no pointer to an alternative tool for broader set lookups, leaving the agent to infer the boundary.

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