library_snapshot_diff

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

Annotations only supply destructiveHint=false. The description adds two genuine behavioral traits beyond that: the operation is purely local with no API/quota cost, and the output shape is added/removed counts plus samples. It does not discuss permissions or failure modes, but for a read-only diff utility this is meaningful extra context.

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 compact sentences with zero waste; the core purpose leads, followed by the quota caveat and output summary. Nothing is repeated from the schema or annotations.

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, and the description compensates by summarizing the return (added/removed counts + samples). Combined with full schema coverage and the local-only note, an agent has almost everything needed; only the differentiation from sibling diff tools 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 description coverage is 100% – all three parameters, including the concise/detailed/json enum for response_format, are documented in the schema itself. The description adds nothing about parameter format or semantics beyond naming the file types, so the 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?

States a specific verb (diff) and specific resources (two sidecar JSON files: library.json or playlists.json) and summarizes the payload (added/removed counts + samples). It implicitly separates itself from sibling diff_playlists by scoping to local snapshot files, though it never names that sibling to make the distinction explicit.

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?

'Quota: local only (no API)' implies when this tool is preferable (offline snapshot comparison vs live API calls), but there is no explicit when/when-not statement or named alternative such as diff_playlists or backup_first. Usage is inferable rather than stated.

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