retime_video

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

With no annotations, the description fully discloses behavioral traits: speed clamping to [0.5, 2.0], ToolError outside range, audio retiming, ffprobe verification, and interpolation behavior (motion interpolation vs frame duplication with default off). This goes well beyond basic expectations and surfaces critical details for agent decision-making.

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?

Six sentences, front-loaded with the core purpose, then logically covering parameter variants, usage scenario, interpolation nuance, constraints, and side effects. Every sentence adds value and the density is appropriate for a tool with 5 parameters and no schema descriptions.

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 absence of annotations and schema descriptions, the description covers all critical aspects: purpose, parameter semantics, constraints, error behavior, audio handling, and verification. It also includes output schema (yes) so return value explanation is unnecessary. The description is fully complete for safe and effective tool invocation.

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 has 0% description coverage, but the description thoroughly explains the key parameters: target_duration_s (speed computed as source/target), speed (1.0 unchanged, 0.5 = half-speed/2x longer), and interpolate (default false, smoothing slow-mo). It also clarifies the mutual exclusivity of speed and target_duration_s, which is essential for correct invocation.

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?

Description opens with 'Stretch/compress a clip to hit a target duration (or explicit speed),' using a specific verb and resource. The primary function is clear and distinct from sibling tools like trim_video (cut) or stitch_videos (combine), establishing unique identity.

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?

Provides a concrete use case: 'Use this to slow a b-roll clip slightly to fill a voiceover segment without repeating footage,' which clarifies when to choose this tool. Lacks explicit exclusion or named alternatives like 'for cutting, use trim_video,' but the contextual guidance is strong and practical.

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