library_snapshot_diff

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

With no annotations provided, the description carries the behavioral disclosure burden. It usefully states that this is local-only with no API calls and that output is added/removed counts plus samples. However, it does not explicitly say the operation is read-only, does not modify the sidecar files, or what happens with invalid/missing paths. These are notable but not severe gaps for a non-mutating diff tool.

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 sentences with no filler. The core action and output are front-loaded, and the quota/safety note is separated clearly. Every sentence earns its place.

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 simple three-parameter local diff tool with no output schema and no annotations, the description covers the essential context: the input files, the kind of diff results, and the local-only quota. It could say a bit more about the direction of the diff (what 'added' vs 'removed' means relative to before/after) and what 'samples' look like, but overall an agent can call this correctly with reasonable confidence.

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?

The schema already documents all three parameters, so baseline is 3. The description adds value beyond the schema by specifying that the paths refer to 'portability/library sidecar JSON files' and narrowing them to 'library.json or playlists.json', which helps the agent select appropriate values. The response_format parameter is already well-described in the schema, so no further compensation is needed.

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 specific verb ('Diff'), a specific resource ('two portability/library sidecar JSON files'), and the output shape ('added/removed counts + samples'). It also names the exact file types (library.json or playlists.json), which distinguishes it from snapshot-diff and playlist-diff siblings without needing to inspect their schemas.

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 use case is implied: you would call this when you have two sidecar JSON files and want to compare them. However, it does not explicitly contrast with closely related siblings like diff_since_snapshot or diff_playlist_snapshots, nor does it state when not to use it. The local-only quota note adds context but is not an alternative-selection guideline.

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