create_media_player

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

Annotations only cover the safety profile (non-destructive, non-idempotent, closed-world), so the description usefully adds the key behavioral quirk that an existing player is returned unchanged with flags not applied, and that both assets are saved. It does not mention permission requirements or failure behavior beyond the listed save_error fields.

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?

Front-loads the create action and the idempotency caveat, and the trailing Returns block is useful since no output schema exists. Slight redundancy: the first sentence lists a subset of return fields that the Returns block then repeats in full.

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?

Because there is no output schema, the description carries the return-value burden and does so with a full field list including error fields. Combined with the idempotency note and derived texture naming, an agent has enough to call it correctly, though failure conditions are only implied.

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 100%, so the baseline is 3, but the description adds meaning beyond the schema by deriving the texture asset name '<name>_T' from the player name and describing the package_path/name path composition. That naming convention is not present in 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?

States a specific verb and resource ('Create a UMediaPlayer asset at package_path/name') plus the optional side effect (linked UMediaTexture) and the save semantics. An agent can tell exactly what asset is produced and where, distinguishing it from sibling creators like create_media_texture or link_media_texture_to_player.

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?

Usage is implied through the optional texture creation and the note that existing players are returned unchanged, but no explicit when-to-use or when-not guidance and no named alternatives (e.g. create_media_texture, link_media_texture_to_player) are offered. Adequate but leaves routing to inference.

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