From a list of beers, return the ones a user has NOT had

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

Annotations already mark it readOnly and idempotent, and the description adds substantial context: it reads the cache only, makes NO API call, consults both cached sources, returns not-had and had bids plus counts and cache freshness, and flags the false-negative risk. This goes well beyond the annotations.

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 core purpose is front-loaded in the first clause, and every sentence earns its place: the use case, the cache-only behavior, the return contents, the prerequisite, and the caveat. It is dense but 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?

For a two-parameter read-only filter tool with no output schema, the description covers the return value, the data sources, the operational prerequisite, and the main failure mode. Nothing essential is missing for an agent to invoke it correctly.

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 100%, so the schema already documents bids and username adequately. The description adds no new parameter-level meaning beyond the schema, matching the baseline of 3.

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 ('return') and resource ('beers a user has NOT had'), and clearly frames it as a filter for venue menus, brewery lineups, or festival lists. It distinguishes itself from opposite tools like untappd_cache_has_had through the explicit 'NOT had' framing.

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 gives clear usage context ('what here is new to me?') and a concrete prerequisite: run untappd_sync_user_beers first. It also warns about false negatives when coverage is incomplete. It stops short of explicitly naming alternatives or saying when not to use it, so it misses the top bar.

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