Extract a setlist ID from a setlist.fm URL

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

Annotations already declare readOnlyHint=true and idempotentHint=true. The description adds substantial behavioral detail: tolerates various URL formats (http/https, www, trailing slash, query/fragment, missing .html), pure local parsing, and error condition if no ID parsed. No contradiction with 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?

Four sentences, each earning its place. The first sentence immediately conveys the core purpose. No redundant information. Efficiently structured with front-loaded key action.

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 simple parsing tool with one parameter, complete annotations, and no output schema, the description fully covers purpose, usage, parameters, behavior, and return format ('Returns {setlistId}'). No gaps remain.

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% with a single 'url' parameter described. The description adds value by providing an example URL format and specifying tolerances (http/https, with/without www, etc.), going beyond the schema's basic description.

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 explicitly states the tool parses a setlist ID from a setlist.fm URL and returns it as {setlistId}. It clearly distinguishes from sibling tools which likely expect an ID directly, not a URL.

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 explicit when-to-use: 'paste a link instead of hunting for the ID' and identifies downstream tools (setlist_get_setlist / setlist_mark_attended). It also specifies what URLs are rejected (artist/venue) and that it is pure local parsing with no network call, giving clear usage boundaries.

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