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

Annotations already declare readOnlyHint, idempotentHint, non-destructive and closed-world, so the safety profile is covered. The description adds genuinely new behavioral facts: 'Deterministic and instant,' plus a preview of the returned structure, which is valuable since no output schema exists.

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?

Two sentences, tightly front-loaded: the output shape first, then the behavioral note, then the usage trigger. No filler or repetition of the title.

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 two-parameter, no-output-schema tool, the description covers the return shape, latency/determinism, and trigger conditions, which is nearly everything an agent needs. Only the length parameter's effect on the outline is left entirely to the schema.

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 100%, with both 'idea' and 'seconds' documented including the enum values and the default of 60, so the schema does the heavy lifting. The description adds no parameter-level detail (it never mentions the seconds/length choice), so the baseline 3 applies.

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 concrete verb ('Plan a short vertical video from an idea') and enumerates the concrete deliverables: hook line, 4–6 beat structure with time ranges, caption tips, CTA, and a tool link. It is clearly a planning/generation tool rather than the sibling find_video_tool's lookup role, though it never names that sibling to sharpen the contrast.

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?

Explicitly says 'Use it when someone wants to plan, outline or script a TikTok, Reel or Short,' which gives a clear triggering context. It stops short of when-not-to-use or naming find_video_tool as the alternative for locating an existing tool.

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