get_library

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

With no annotations, the description carries full burden and it delivers: it discloses the deletion-never-in-delta limitation, the skipped counter semantics, and the obligation to surface non-zero skipped to the user. It also defines the read-only nature by its opening verb.

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 description is compact and front-loaded: purpose first, then each parameter, then caveats. Every sentence adds operational value; no filler or repetition.

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 read tool with a present output schema, the description covers the non-obvious behavior (deltas, deletions, skipped holes) that the schema cannot convey, and gives enough parameter detail to make the correct call without external lookup.

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 0% and there are no enums, yet the description fully documents all three parameters: valid values for type, valid statuses, omission behavior, and the exact date_from contract ('ISO timestamp from get_activities, passed back byte-for-byte').

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?

Opens with 'Read the watch history and watchlists,' a specific verb plus resource that immediately distinguishes this from sibling tools like get_activities (activity log) and get_library_ids (ID diffing). The rest of the description reinforces the scope with filtering dimensions.

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?

Explicitly explains the delta mode ('With it you get only what changed since; without it, the full library') and gives a when-not condition: 'Deletions never appear in a delta... call get_library_ids and diff instead.' This is actionable routing guidance.

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