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

Annotations only declare readOnlyHint and openWorldHint; the description adds real behavioral context beyond them: the 5 quota-unit cost, and the 'omitted' behavior explaining that ids not in the catalog or lacking audio features are silently dropped rather than erroring. It does not cover auth or rate limits, but the quota and partial-failure disclosure is substantive.

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?

Front-loaded with the core action and scope in the first sentence, followed by the arc vocabulary, then behavior. It is slightly padded by enumerating return fields (arc, count, flow_score, tracks, transitions, omitted) that the output schema already defines, but the list is compact and each item is short.

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 read-only tool with an output schema, the description is close to complete: it gives purpose, arc semantics, quota cost, and partial-result behavior. The only redundancy is restating return fields already in the output schema, and the only gap is that start_track_id's fixed-opener role lives solely in the schema.

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%, so the baseline is 3. The description adds genuine meaning for `arc` by explaining the shape of each curve ('peak_time builds to a peak then eases'), which the schema's flat enum list does not convey. It does not mention start_track_id at all, but that parameter is fully documented in the schema.

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+resource+scope: 'Order a crate of 2-100 catalog tracks into a beat-matched DJ set that follows an energy arc.' This is clearly distinguishable from siblings like suggest_next_track or score_transition, which operate per-step rather than over a whole crate.

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?

Usage is implied by the batch nature of the tool ('order a crate'), and the export hint shows the downstream workflow, but there is no explicit when-to-use-this vs. suggest_next_track/score_transition guidance or any exclusion. The agent must infer that this is the whole-set counterpart to the per-transition tools.

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