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

Annotations already establish a safe, public read (readOnlyHint, openWorldHint), so the description is free to add what annotations cannot: the 1-credit cost and the split between the default payload and what only appears in `raw`. That cost disclosure is exactly the kind of behavioral context an agent needs before deciding how often to call. It stops short of noting caching behavior despite exposing cache_max_age.

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 short sentences, each doing distinct work: purpose, returned fields, raw-only fields with the enabling flag, and cost. Front-loaded with the answer and nothing 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?

With no output schema, the description carries the burden of describing returns, and it does so by enumerating the default fields and the raw-only additions. Two gaps remain: cache_max_age is never explained, and include_raw is described as a parameter that the schema does not declare, so an agent reading the schema alone would be misled.

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%: `id` is documented, `cache_max_age` is not documented anywhere. The description partially compensates by explaining the effect of include_raw, but it never mentions cache_max_age, and worse, include_raw is not present in the input schema at all.

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 resource (Spotify album) and enumerates the concrete fields returned (title, artist, release date, artwork, runtime), which is more informative than the bare title. It does not explicitly distinguish itself from spotify_track, spotify_artist or appleMusic_album, so sibling differentiation is left to the name and the album-specific field list.

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 one actionable usage rule — add include_raw=true to pull the track listing, release type and track count out of `raw` — which tells the agent when the extra data is worth fetching. It offers no guidance on when to pick this over spotify_search or spotify_track, and no prerequisites beyond the implicit album id.

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