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

Annotations already declare read-only and open-world behavior, but the description adds valuable context: credit cost and a clear partition of response data (top-level fields vs `raw` containing monthly listeners and top tracks). 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?

Three short sentences, front-loaded with the core purpose, and every sentence adds relevant information (purpose, return scope, cost) without waste.

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 read-only tool with no output schema, the description adequately covers returned fields and cost. It falls short on usage alternatives and the meaning of `cache_max_age`, but overall gives enough context to call 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 coverage is 50% – the `id` parameter is well-described, but `cache_max_age` is undocumented in both schema and description. The description provides no parameter guidance or syntax details to compensate for the gap.

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?

States a specific verb (retrieves details) and resource (Spotify artist), and enumerates the returned fields (name, follower count, biography, artwork, links), clearly distinguishing it from sibling tools like spotify_album or spotify_track.

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?

Implies usage for fetching artist information, but does not explicitly say when to use this tool versus spotify_search or other artist tools, nor does it provide exclusions. The credit cost note is a useful usage hint.

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