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

Annotations already declare readOnlyHint, openWorldHint, and idempotentHint, so the description only needs to add extra context. It adds that releases are excluded due to size and that they can be browsed separately, which is important behavioral disclosure not captured by annotations. 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?

The description is two sentences: the first lists the returned fields, the second explains the release exclusion and points to an alternative. It is front-loaded, informative, and contains no fluff.

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 single-parameter lookup tool with an output schema, the description fully covers what the tool returns, what it excludes, and how to get the excluded data. Combined with annotations, it provides complete guidance for effective use.

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 'mbid' as 'Label MBID (36-character UUID)'. The description only repeats 'by MBID' without adding new parameter semantics, yielding the baseline score for high coverage.

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 'Label by MBID' and lists the specific data fields (type, country, life span, label code, area, aliases, tags, external links). It distinguishes from sibling tools by focusing on the label entity and explicitly notes that releases are not included, differentiating from browse_entities.

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 explicitly says 'they are NOT embedded here — enumerate them with musicbrainz_browse_entities (target_type=release, link.label)', providing a clear when-not-to-use and naming the alternative tool. It also implies when to use this tool (when label details are needed) implicitly.

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