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

Annotations already declare readOnly, idempotent, openWorld and non-destructive, so safety is covered. The description adds value beyond that by enumerating the return payload (ids, names, artists, album, release date), which matters since there is no output schema. It stops short of disclosing empty-result or multi-match behavior.

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?

A single compact sentence pair with the identifying concept and example front-loaded, followed by the return shape. No filler, no restatement of the title.

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 one-parameter read-only lookup with full annotation coverage, the definition covers purpose, input form, and return fields. The only gap is edge-case behavior, such as what is returned when the ISRC resolves to nothing or to multiple tracks.

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% and the schema already documents the length bounds and that spaces/dashes are ignored. The description contributes only a sample ISRC value, which is marginally useful but adds no semantics the schema lacks; baseline 3 applies.

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 states a specific verb ('Find') and resource ('Spotify track(s) for an ISRC'), defines the acronym, and supplies a concrete example value. This is clearly distinct from siblings like search or get_tracks, which are not keyed by ISRC.

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 resource type: if you hold an ISRC, this is the tool. But the description never explicitly says when to prefer it over search, nor does it name alternatives or any when-not condition. An agent must infer the routing.

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