create_media_subscriptions

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

Annotations already indicate the operation is not read-only, is idempotent, and is non-destructive, so the description need not repeat that. It adds behavioral context by noting the playlist exception and the required ratingKey hint for downloads, but it does not detail side effects or post-creation behavior. This is reasonable given annotation coverage.

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 core purpose is front-loaded in the first line, and the argument descriptions follow a clean list. The sub-bullets under 'params' are slightly awkward, but they convey needed detail in a compact way. It is not over-engineered and every sentence carries meaning.

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?

With an output schema available and a domain-normal concept, the description adequately explains how to pass each parameter and the circumstances that modify them. It could state the higher-level purpose of a subscription more explicitly, but it is sufficient for an agent to invoke this tool correctly.

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 0%, so the description must document the parameters itself, and it does so for all 6. For instance, target_library_section_id is described as the section into which media will be grabbed and extra notes clarify its necessity, while hints includes the ratingKey requirement. The descriptions of prefs and params are thin, but still offer a meaning plus an example sub-parameter, which is above baseline.

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 creates a subscription and provides the POST /media/subscriptions endpoint, making the verb, resource, and intent specific. It does not explicitly differentiate itself from the sibling create_media_subscriptions_process, but the name and sentence are enough to distinguish it from update/delete/list tools.

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 gives no explicit comparison to alternative tools, but it does include useful conditional usage hints: 'Not actually required when the subscription is to a playlist' and the requirement that ratingKey is needed for PMS remote downloads. These imply scenarios in which the tool is appropriate, though they are parameter-level guidance rather than tool-level decision rules.

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