mix_meters

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

Annotations already cover the safe-read profile (readOnly, idempotent, non-destructive), yet the description adds two non-obvious traits: readings are meaningless unless the transport is running, and null means silence or not-yet-measured. It does not describe snapshot timing/latency or per-frame vs averaged semantics, which keeps it at 4.

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?

Front-loaded with the resource and return contents, then the operational constraint, then the null convention. Dense but every clause carries information; the caveat is placed after the payload rather than buried.

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?

No output schema exists, so the description must carry return-value semantics — and it does, enumerating peak/RMS in dBFS, momentary/short-term/integrated LUFS, true peak dBTP, stereo correlation and LU range. Combined with the null convention and playback precondition, nothing needed to interpret the response is missing.

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% and the single 'tracks' parameter is fully documented in-schema, including the UUID-vs-index distinction and default. The description adds nothing about parameter behavior (e.g. whether master is always included), so 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?

Specific verb and resource ('Live levels, as the mixer meters show them') followed by an exact inventory of what is returned per track and on the master. It is clearly separable from the static 'mixer_get' and from offline analysis tools in the sibling list.

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?

'Meters only move while audio plays: start the transport, wait a few seconds, then read' gives a concrete when-and-how sequence tied to transport_play. It does not name alternatives such as analysis_capture or analysis_file (offline measurement), so it stops short of full alternative routing.

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