create_storyboard

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

Annotations already declare readOnlyHint=false and openWorldHint=false, so the mutation profile is known; the description adds real value by stating no model API is invoked (assistant-authored content), how durations are auto-derived from word count, and the safety rule that narration is shortened rather than silently cut. It does not say whether the plan is persisted or returned, which keeps it short of a 5.

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?

Four front-loaded sentences that each contribute something: the scene shape first, then the no-API behavior, then the duration rule, then branding and text-fitting constraints. Dense but without filler; minor compactness loss from splitting the duration and branding rules into separate lines.

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?

An output schema exists and annotations cover the safety profile, lowering the burden, and the description handles the trickiest part (untyped scene objects and duration derivation). Still, for an 8-parameter creation tool with zero schema descriptions, leaving the audio/visual parameters (voice, aspect, music, caption_style, music_volume) unexplained and omitting any mention of preview/generate sequencing leaves clear gaps.

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 coverage is 0% across 8 parameters, so the description must carry the load. It documents the nested scene fields (text, query, asset_id, duration_seconds), branding keys (title, footer, color, logo_asset_id) and the total duration_seconds semantics, which is valuable given the untyped scene items. However, music, voice, aspect, music_volume and caption_style receive no mention at all.

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 ('Plan explicit scenes') and enumerates the scene fields (text, query, asset_id, duration_seconds), so the agent knows this builds a storyboard plan rather than rendering or fetching one. It never names siblings like generate_video or preview_storyboard, so differentiation is only implicit from the word 'plan'.

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 line 'The assistant writes the scenes; no model API is called' clarifies the mode of operation but not when to choose this over preview_storyboard or generate_video. The duration rule ('Set every scene duration or let the planner divide the total by word count') is a useful usage instruction, but there are no explicit exclusions or sequencing guidance.

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