create_player_playback_set_text_stream

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

Annotations already indicate non-read-only, idempotent, and non-destructive behavior. The description adds only the endpoint, not behavioral context such as whether an active playback session is required, whether this replaces the current subtitle track, whether the change persists, or what happens when stream_id is null. It does not contradict annotations, but it adds little beyond them.

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 short, but the brevity comes from under-specification rather than efficient writing. The endpoint line is useful, but the Args section duplicates what the schema already shows and the core meaning of the tool is left vague. It is terse without being informative.

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?

Despite having only one parameter, an output schema, and annotations, the description fails to explain the tool's actual role in playback control, when it should be invoked, or how stream_id is used. An agent cannot confidently select this tool over the many playback-related siblings.

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?

With 0% schema description coverage, the description carries full responsibility for explaining stream_id. It merely calls it 'the unique identifier of the stream,' which essentially restates the parameter name and does not clarify what kind of stream ID is expected, how to obtain it, or whether null means 'clear the text stream.' This minimally compensates for the schema gap.

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 a concrete verb and resource ('Set Text Stream') and includes the endpoint, so an agent can roughly infer this tool changes the active text/subtitle stream. However, it does not explain what 'text stream' means in the playback domain, and among siblings like create_player_playback_subtitle_stream and create_player_playback_set_streams, it does not differentiate itself.

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?

No guidance is given on when to use this tool versus closely related playback controls such as create_player_playback_subtitle_stream, create_player_playback_video_stream, or create_player_playback_set_streams. The description provides no prerequisites, no alternative recommendations, and no exclusions.

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