play_midi_file

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

With no annotations, the description carries the full behavioral burden. It discloses only that playback is real-time to a synthesizer/sound module; it says nothing about whether the call blocks until the file finishes, how long playback lasts, how failures (bad path, busy device) are reported, or whether devices must exist beforehand.

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?

Two short sentences, front-loaded with the action and resource, with no filler. The second sentence is somewhat redundant with the first ('sends ... for real-time playback' restates 'play'), but the whole definition is efficiently sized.

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?

An output schema exists, so return values need not be explained, and both parameters are documented. Still, for a playback tool with no annotations, the description omits blocking/async behavior and device prerequisites, leaving meaningful gaps for correct invocation.

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 coverage is 100%, so midi_file and device_index are already documented with types and a default. The description implies the device-selection concept but adds no syntax, path format, or guidance on obtaining a valid device index, so it does not exceed the schema baseline.

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 concrete verb+resource ('Play a MIDI file') and names the destination ('through an output device'), which is far more specific than the bare name. It does not, however, distinguish itself from siblings like send_midi_note, midi_to_reaper, or list_midi_devices, so the agent must infer the boundary.

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?

There is no explicit when-to-use guidance and no named alternatives, despite a crowded sibling set (send_midi_note, midi_to_reaper, record_midi_performance). The phrase 'through an output device' hints that a device must be chosen, but nothing tells the agent when to pick this tool over the others or that list_midi_devices is a prerequisite.

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