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

Beyond the readOnly/idempotent/destructive annotations, the description discloses substantial behavior: negatives are enforced, vague/typoed briefs are not rejected, assumptions will be reported, composer names flip sorting, and the tool should never claim a track is missing without first searching by subject. This is exactly the kind of non-obvious behavior an agent needs.

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 longer than the intuitive tool, but nearly every sentence affects agent behavior: language handling, search-with-assumptions policy, negatives, and the examples package. It is still somewhat-packed and prescriptive, and could be trimmed slightly while losing none of its value, so 4 is appropriate.

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 search-type tool with read-only/idempotent annotations, this description covers all required call semantics: how to speak about the query, the output of exact name queries, edge cases like composer-inside-brief, and the non-obvious never-tell-not-found rule. The return format is not described, but the tool has no output schema and the purpose clearly implies a result list; nothing needed to invoke the tool correctly is missing.

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?

The schema would describe 'brief' only as text that can be an exact name, but the tool description dramatically expands that: mood/scene/genre/energy/instruments, free-form examples, translation instructions, the full range of accepted exact identifiers (track, album, catalogue number, composer), and negative search behavior. However, it does not supplement the inexplicably named 'top_k' parameter beyond the schema default of 10.

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 gives a clear, specific verb and resource: 'Find AINSOF music from a written brief—mood, scene, genre, energy, instruments'. It also covers query-by-name and composer, so an agent can tell what the tool will do. It does not explicitly contrast with siblings like find_soundtrack or search_by_reference, so despite clear purpose it stops short of a full 5.

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 actionable guidance: translate non-English briefs, send appréciation in user's language, treat negatives as enforced, and search anyway on vague queries rather than asking for clarification. It also explains the composer-in-brief behavior and the exact-match name paths. No alternative sibling is ever named or excluded, so there is no explicit optimal-alternative guidance.

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