get_lesson_frame

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

With no annotations, the description carries the full behavioral disclosure burden. It covers the write side effect to save_path (including ~ and $VAR expansion, parent dir creation, and absolute path in response), the conditional inline image via include_image, the ffmpeg dependency, and the return shape involving JSON summary, caption, and inline image.

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 one-sentence summary is front-loaded, followed by a compact Args block where each line adds a distinct detail. No sentence is wasted; the return behavior and external dependency are stated in two short sentences at the end.

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 no output schema and no annotations, the description is complete for a 6-parameter tool: it documents every parameter, prerequisites from sibling tools, return format, optional image inclusion, file path behavior, and the ffmpeg requirement. An agent has enough information to invoke it correctly.

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 must fully explain every parameter, and it does. Each of the six parameters gets meaningful guidance: provenance for slugs, timestamp meaning, quality resolution/speed, save_path side effects, and include_image behavior including its default.

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 opens with a specific verb and resource: 'Screenshot a single video frame from a lesson at the given timestamp.' This clearly distinguishes the tool from sibling tools such as transcripts and slides, which serve different resources and purposes.

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 description gives clear usage context: which slugs come from which sibling tools, the quality/speed tradeoff, and the save_path/include_image usage pattern. It does not explicitly state when to prefer this over get_lesson_transcript or get_lesson_slides, but the purpose and dependencies are clear enough to guide selection.

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