mark_unwatched

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

Beyond readOnlyHint=false and destructiveHint=false, the description discloses an operational gate with the environment variable requirement, which is important behavioral context because the tool likely fails without it. It does not detail side effects or return behavior, but the mutability and prerequisite are clear.

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 one sentence, action-first, and includes the key prerequisite in a parenthetical with zero wasted words. It avoids restating the title or repeating information already present in 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?

For a simple single-parameter mutation with no nested objects and no output schema, this description covers the action, the required parameter, and the key prerequisite. The only minor gap is not describing the expected successful response or failure behavior, which is not critical for deciding how to invoke it.

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 schema already documents the only parameter, ratingKey, with a meaningful description and 100% coverage. The tool description adds no extra parameter-level detail beyond reinforcing that the item is a Plex media item, so no compensation is needed.

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 names a specific action ('Mark'), a specific resource ('a Plex media item'), and the resulting state ('unwatched'). It is also semantically distinguishable from the sibling tool mark_watched without needing to open the schema.

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 intention is self-evident and the required environment gate is stated, so an agent can infer when to use it. However, it does not explicitly mention alternatives such as mark_watched or state when the opposite tool should be preferred.

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