Resolve an Untappd URL

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

Annotations already declare readOnlyHint and idempotentHint. The description goes beyond by stating 'Pure local parsing — no network' and 'Read-only', confirming the safety profile. It also reveals that it outputs the entity type, id, and the next tool to call, which is a behavioral trait not in 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 description is two sentences long, front-loaded with the main action ('Parse an untappd.com URL...') and essential constraints ('Pure local parsing — no network. Read-only.'). Every word adds value; no redundancy.

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?

Despite no output schema, the description explains the return value (entity type, id, and next tool to call). It covers constraints (local, read-only, no network). For a single-parameter tool with straightforward behavior, the description is fully complete.

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?

The input schema describes only one parameter 'url' with a generic description. The description adds significant meaning by enumerating the accepted URL formats: /b/, /w/, /v/, /user/, and check-in links, which helps the agent construct valid inputs. Schema coverage is 100%, and the description compensates fully.

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 states the tool's purpose: parse an untappd.com URL into entity type and id, and name the next tool to call. It specifies the URL types (beer, brewery, venue, user, check-in). This distinguishes it from sibling tools which are actions, not resolvers.

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 provides clear usage context: it's a parser for untappd URLs, local and read-only. It implicitly tells when to use (when you have a URL), but does not explicitly state when not to use or compare with alternatives among siblings. However, its unique role as a resolver makes usage clear.

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