theory_borrowed_chords

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

With no annotations, the description carries the full burden. 'Return' signals a read-only lookup and the mention of 'usage notes' hints at the output, but the description does not disclose return format, scope limits beyond major keys, or whether this is purely static reference data.

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?

One concise sentence with no filler. It front-loads the action and resource, then adds the key qualifier 'for major keys' and the useful detail about usage notes.

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 zero-parameter reference tool, the description covers the resource, scope, and output nature. It could be more explicit about the exact structure of the returned palette, but nothing critical is missing for an agent to invoke it.

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 tool has zero parameters, so the input schema is already complete and the description has nothing to add. Baseline 4 applies because no parameter documentation is needed.

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 action ('Return') on a specific resource ('borrowed-chord palette for major keys') with a clear qualifier ('modal interchange'). It is easily distinguished from sibling theory tools like theory_diatonic_chords and theory_modes because it names a unique musical concept.

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 implies when to use the tool—when a borrowed-chord/modal-interchange palette is needed—but it does not explicitly state when not to use it or name alternatives. There is no exclusion guidance or routing to related theory tools.

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