Audio/video metadata

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

Annotations already declare readOnlyHint=true, idempotentHint=true, and openWorldHint=false, so safety is covered; the description adds genuine extra context: processing is offline, files are streamed so arbitrarily large inputs are fine, and VBR MP3s without a header require a full file scan (a real performance cost an agent should anticipate). That is exactly the kind of beyond-schema behavioral disclosure that earns a top score.

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 purpose lead is front-loaded and the field/format enumerations are dense but each list item carries routing value. The final VBR sentence is a useful edge-case note. It is long for a one-parameter tool but not padded with 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?

With no output schema, the description effectively enumerates the returned metadata fields (including per-track video dimensions), so an agent knows what it will get. Combined with 100% schema coverage and full annotation coverage, nothing needed to call this tool correctly 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 parameter's description already documents absolute paths, paths relative to --root, and raw or data: URI base64. The description reinforces this ('File path (streamed, any size) or base64') and adds the streaming/any-size caveat, giving modest value beyond the schema rather than repeating it outright.

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?

States a specific verb and resource ('Read audio and video file metadata offline') and immediately enumerates the exact fields returned (container, codec, duration, bitrate, tags, cover art), which makes it unmistakable next to siblings like pdf_metadata_read, image_exif_read, or ai_file_identify. The explicit format list further removes any ambiguity about scope.

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?

Usage is only implied: the description notes the offline nature and the accepted input forms (path or base64), which tells an agent this is the right tool when an audio/video container is involved. However, it never states when NOT to use it or names an alternative (e.g., use pdf_metadata_read for PDFs, image_exif_read for images), so routing is left to inference from the format list.

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