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

Annotations already declare the full profile (mutation, idempotent, open-world, destructiveHint=true), so the bar is lower. The description usefully adds that the change applies live without interrupting playback, but this sits oddly against destructiveHint=true and it says nothing about persistence across streams, permissions, or latency.

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 operative instruction is front-loaded in the first sentence. The middle sentence ('This is the point of streaming over generated tracks...') is motivational filler rather than actionable content, though it is short.

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 tool with an output schema present, the essentials are covered and return values need not be explained. The main omission is the precondition of an active stream and what happens if none exists.

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 single 'intensity' parameter already documents low/medium/high with their meanings. The description adds no value-mapping or format detail beyond that, so the 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 gives a specific verb and resource ('Change the energy of the running stream') plus a scoping qualifier ('without interrupting playback') that separates it from start_stream, restart_stream, and set_stream_loop. It never names those siblings explicitly, so differentiation is inferential rather than stated.

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?

It offers concrete use cases ('follow a workout's phases or a game's tension'), which implies context, but gives no when-not guidance and no comparison to the sibling streaming tools. The precondition that a stream must already be running is only implied by 'the running stream'.

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