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

Annotations already cover safety (readOnly, openWorld, non-destructive), and the description goes well beyond them: it discloses that no artist graph exists, explains the borrowed-data approximation, details the scoring adjustments (top-3 track similarities, same-genre lift, cross-genre penalty), and states a concrete cost of 2 quota units.

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?

It is front-loaded (purpose first, then derivation, then return shape, then chaining, then cost) and the algorithmic sentences earn their place by explaining how to interpret scores. It is slightly long for a two-parameter tool, and the return-shape sentence partly duplicates the existing output schema.

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 derived-recommendation tool, the description covers origin of the data, scoring rationale, output fields, chaining, and cost. An output schema exists so return values need not be spelled out, and the only real gap is the numeric range/interpretation of `score`.

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 both `artist` and `limit` are already documented in structured fields, and the description adds no syntax or format detail beyond calling it a "seed artist." Baseline 3 is appropriate since the schema does the heavy lifting.

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 opens with a specific verb+resource ("Artists related to a seed artist") and pins down the exact output contract (Spotify's retired related-artists shape). The derivation detail (track-vector centroid -> nearest tracks -> artist aggregation) makes it unmistakable versus siblings like get_recommendations or suggest_next_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?

It gives explicit downstream routing ("Pass a sample_track_id straight to get_audio_features or suggest_next_track"), which tells the agent where to go next. It does not, however, say when to prefer this over get_recommendations or suggest_next_track for artist discovery, so the choice between recommendation-type siblings is left to inference.

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