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

The description adds behavioral context beyond the annotations. It notes the tool 'Free (requires an active plan),' implies a write operation (consistent with readOnlyHint=false), mentions it returns warnings and that the actual duration may differ from requested, and that scenario_id is 'valid for a few days.' These details inform the agent of side effects and constraints without contradicting the 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 relatively long but well-structured, with clear sections for behavior, parameters, return values, and typical flow. It front-loads the key information about plan requirement and the one-call behavior. While every sentence adds value, the length is slightly above the minimum needed, but it remains efficient and organized.

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?

The description covers all essential aspects: prerequisites (active plan), behavior (no questions, one call), parameter semantics for non-obvious fields, return values (scenario_id, text, episodes, warnings, duration), and the integration flow with sibling tools. Since an output schema exists, the description need not detail the exact structure, but it provides enough for an agent to call the tool correctly and handle the result appropriately.

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 schema description coverage at 0%, the description compensates by explaining key parameters: 'duration_sec 5..60' (range), 'aspect 9:16 | 16:9 | 1:1' (enum values), and 'reference_urls: public image URLs of a product/character (or reference_id `ref_...`), optional.' It does not explicitly describe idea, category, or language, but these are either self-explanatory or less critical. The description adds meaningful semantics for the parameters that are most ambiguous.

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 clearly states the tool's purpose: 'Tessa writes a complete video scenario from an idea in one call.' It uses a specific verb (writes), a resource (video scenario), and a clear input (idea). It also distinguishes itself from siblings by outlining a typical flow that includes other tools like tegas_find_heroes and tegas_start_video, so an agent can see where this tool fits in the overall process.

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 provides an explicit typical flow: 'tegas_write_scenario -> (optional) tegas_find_heroes / tegas_draw_heroes -> tegas_start_video with confirm=false to get the price -> user consent -> confirm=true -> tegas_wait_video.' It also instructs to 'call again with a refined idea if they want changes,' giving clear when-to-use guidance and integration with adjacent tools. It even notes the tool does not ask questions, so users should refine the idea for changes.

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