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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds behavioral richness: it reports uncertainty ('report where the analysis is uncertain instead of guessing') and notes the provenance of results (same module as Key Assistant and Chromatic Grid). This goes beyond what annotations provide.

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 three sentences, each earning its place: purpose, usage guidance, and behavioral context. It is front-loaded with the core action and free of redundant filler.

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 simple read-only analysis tool with one parameter and no output schema, the description is quite complete: it explains what is analyzed, that nothing is changed, when to use it, and how it handles uncertainty. It could include what the returned analysis looks like, but that is not essential for the core understanding.

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%, and the schema parameter description already explains the format ('The UUID after /s/ in a Keyboardia share URL. Pass only the UUID'). The tool description does not add parameter-specific details, but it doesn't need to since the schema is complete. This is the baseline 3 for full schema coverage.

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 ('Describe what is happening musically in a session') and lists concrete musical attributes (rhythm, pitch content, inferred key, chords). It also distinguishes itself from editing by saying 'Use this to explain music rather than to edit it', which clearly separates it from sibling tools like edit_session.

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 explicitly tells when to use it ('to explain music rather than to edit it') and clarifies it changes nothing. It does not enumerate all sibling alternatives, but it gives a clear usage contrast with editing. The context also implies it is for analysis, which is distinct from fetching or exporting.

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