extract_stream

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

No annotations are provided, so the description carries the full behavioral burden. 'Losslessly' is a genuinely useful behavioral trait (no re-encoding), but it is silent on overwrite behavior when the output exists, error conditions for an invalid index, and permission requirements. The presence of an output schema relieves it of return-value explanation.

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?

A single tight sentence with no filler, and the most decision-relevant information (single stream, absolute index source, lossless) is front-loaded.

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 four-parameter extraction tool with an output schema, the description covers the essential selector and the lossless guarantee. The main remaining gap is overwrite semantics, which is a modest omission for a straightforward utility.

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 all four parameters are undocumented in the schema. The description clarifies the most ambiguous one ('absolute index from probe_media'), but leaves input path format, output path format, and the overwrite flag's effect entirely unexplained.

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 ('Extract a single stream') and adds the distinguishing scope 'by absolute index' plus 'losslessly'. That differentiates it from the more targeted sibling extract_audio, though the description never names that sibling explicitly.

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 parenthetical 'from probe_media' implies the caller should run probe_media first to obtain the index, which is useful implicit sequencing. However, it gives no when-not guidance or explicit statement that extract_audio is the preferred route for audio-only extraction.

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