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

Annotations already declare readOnly, idempotent, non-destructive, so the safety bar is low; the description still adds real behavioral context — an in-chat browser session, the specific checks performed, a 30-second preview beside the original, and an account requirement for full mastering. It stays silent on what artifact (if any) is produced, but the workflow disclosure is genuinely useful.

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?

Three sentences, front-loaded with the action and then the resulting experience; no filler. Slightly over-detailed on the preview mechanics relative to the sibling-routing gap, but appropriately sized overall.

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 no-required-param, annotation-covered, fully-documented-schema tool, the description is largely adequate, and the missing output schema means return values needn't be explained. What is missing is disambiguation from the crowded mastering sibling set and whether the preview produces a persistent mastered file.

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 description coverage is 100%, with both enum parameters (genre, preset) fully documented in the schema, so the baseline is 3. The description mentions neither parameter and adds no meaning beyond what the schema already conveys.

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: it opens the Bandmixr studio to master or enhance a finished stereo mix, and it describes the concrete flow (browser check of loudness/peaks/stereo/tonal balance, 30-second preview). However, it never distinguishes itself from close siblings like start_mastering, open_song_studio, mix_and_master, or prepare_full_master, so an agent has to guess where this fits.

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 only implied through the input condition 'a finished song (a stereo mix)' and the note that full mastering requires a Bandmixr account. There is no explicit when-to-use/when-not guidance and no routing to the obviously overlapping mastering siblings, leaving the agent to infer the boundary.

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