create_library_metadata_by_ids_extras

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

The description only says 'Add to an item's extras' and lists args. It doesn't explain whether extras are appended or overwritten, what the effect of repeated calls is (though idempotentHint is present), or any auth/rate-limit context. Annotations cover idempotency and non-destructiveness, but the description adds no extra behavioral detail.

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 extremely concise: a one-line summary, an endpoint line, and a list of args. No fluff, and the main verb is front-loaded. However, its brevity borders on under-specification, so it's not perfect.

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?

The tool has an output schema and annotations, so return values and safety profile are covered. But given the tool's mutating nature and the need to distinguish extras from other metadata types, the description lacks essential context about what 'extras' are, valid extra_type values, and when to call this. Minimal completeness.

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 description provides one-line explanations for each parameter, clarifying that ids are comma-separated, extra_type is a metadata type, and url is the URL. However, it doesn't explain possible values for extra_type or the role of url in the request. With 0% schema description coverage, this is better than nothing but still incomplete.

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 'Add to an item's extras' which is a clear verb and resource. However, it doesn't differentiate from sibling tools like create_library_metadata_by_ids_marker or create_library_metadata_by_id_arts; the name itself does most of the differentiation.

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?

There is no guidance on when to use this tool instead of alternative create operations for library metadata. No mention of alternatives, prerequisites, or scenarios. Only a bare description of the operation.

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