items_apply

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

With no annotations, the description discloses critical behavior: non-delete changes applied first in input order, deletes last in descending item_index order, and errors do not abort the batch. It clearly indicates mutation (set/delete). A point deducted for not specifying authorization or undo behavior.

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 front-loaded with a concise summary, then a structured Args section. Every sentence provides essential information (ordering, error handling) without redundancy. It is thorough yet efficient.

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 batch mutation tool with no output schema, the description covers parameter format, ordering, and error behavior. It mentions a 'response's errors array' but does not detail the full return structure. This is a minor gap given the complexity.

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 input schema has 0% description coverage, but the description completely explains the 'entries' parameter: it is a JSON array with required item_index and optional fields, including delete. Examples clarify the format, adding immense value beyond the schema.

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 clearly states it batch-sets properties (position, length, volume_db, mute, fade_in, fade_out) or deletes items. It specifies the verb 'apply' and resource 'items', distinguishing it from single-item tools like item_set_volume or item_delete.

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 description explains when to use this tool (for batch operations), and provides detailed ordering semantics to avoid index shift issues. It implicitly differentiates from single-item siblings, but does not explicitly state when not to use it or alternative tools.

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