get_library_streams_by_stream_id_ext

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

Annotations already cover readOnlyHint, openWorldHint, idempotentHint, and non-destructiveness. The description adds meaningful behavioral detail beyond annotations: `ext` is required for subtitle fetching, `encoding` and `format` only apply to text subtitles, and `auto_adjust_subtitle` optionally adjusts subtitle timestamps. This clarifies behavior without contradicting annotations.

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 tight and well-structured: a one-line summary, the endpoint path, and an Args list covering every parameter with no redundant prose. Every sentence earns its place.

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?

Given the output schema exists, return format does not need explanation. The description covers all parameters and their semantics. However, it omits expected extension values, potential error conditions, and any indication of alternative stream-related tools, leaving an agent to infer when this endpoint is the right choice.

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 carries full responsibility for parameter meaning. It provides clear semantic explanations for all five parameters, including conditions like 'only used for text subtitles' and the required nature of `ext` for the `sub` portion. This fully 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 'Get a stream.' with the endpoint path, making clear this is a read operation on a specific stream resource. However, it does not differentiate from sibling get_library_streams_by_stream_id_levels or get_library_streams_by_stream_id_loudness, which also operate on streams.

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 alternatives. The parameter description for `ext` explains that it is required for the `sub` portion of `idx`/`sub` subtitles, which is partial param-level guidance, but there is no tool-level usage context or exclusion criteria.

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