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

Adds rich behavior beyond the annotations: the call is refused and nothing is written unless rights_confirmed is sent, the account artist can never be removed, an empty list clears billing, and dry_run previews without writing. The legal-confirmation recording is a significant disclosure the annotations cannot express.

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 nearly every sentence carries a distinct rule (ordering, refusal, clearing, sibling routing). It is dense rather than padded, though the single long paragraph could be broken up for faster scanning.

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 5-param mutation tool with no output schema, the description supplies the prerequisites, refusal conditions, idempotent-clearing behavior, and the alternative tool. An agent has everything needed to call it correctly.

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 80%, so the baseline would be 3, but the description adds real meaning: it explains what each role value does to the credit line (primary/with join the main credit, featured/remixer become the feat. part) and the exact semantics of rights_confirmed. Only dry_run and the label-only artist param are not elaborated in prose.

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 (Replace) and resource (the OTHER artists a track is billed to), and illustrates the exact output line on every store. It explicitly distinguishes itself from set_track_credits, the sibling that handles songwriter/performer/producer credits.

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?

Explicit when-to-use, when-not (do not send the account's own artist, which is always billed first), ordering requirement, and named alternative (set_track_credits). It also routes the rights_confirmed workflow with a precise confirmation rule, so the agent knows both the preconditions and the fallback.

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