ui_open_piano_roll_for_channel

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

With no annotations, the description carries the full burden, and it does well: it discloses that the window will not close, that selecting a pattern can auto-select the channel, and that openEventEditor is only invoked as a last resort. It is honest about the fallback behavior, though it does not cover error cases or what happens if the channel/pattern cannot be matched.

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 compact and front-loaded with the core purpose, and the second paragraph earns its place by explaining an important behavioral nuance. There is no redundant wording or unnecessary repetition of the schema.

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?

The behavioral context is strong, but the description leaves gaps in parameter semantics and does not mention return/error behavior. For a tool with no output schema and no annotations, it is adequate but not fully complete for an agent to confidently invoke it in all edge cases.

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 0%, so the description must explain parameter meaning, but it only refers to 'a given channel/pattern' and 'pattern switch.' It does not clarify that channel is a required integer, that pattern is optional and defaults to null, what IDs mean, or how the two parameters interact.

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 first sentence clearly states the action—switching the piano roll to show a given channel/pattern—and adds the important qualifier 'without closing the window.' It is specific and not a tautology, but it does not explicitly differentiate from sibling tools like piano_roll_goto or ui_scroll_to_channel, so it falls just short of a 5.

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 gives useful context about one-channel-per-pattern mode and when openEventEditor is used as a fallback, but it never explicitly says when to choose this tool over its siblings. The usage guidance is implied rather than stated as clear conditions or exclusions.

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