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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=false, so the safety profile is covered. The description adds genuine context beyond that: what the response contains (product/doc URLs, exact tool names, ordered steps, example requests, follow-up edits, review criteria) and the negative guarantees about credits and account access. It does not cover behavior on invalid input or whether the guide content is static/cached.

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 tight sentences with the action and coverage front-loaded and the side-effect boundary in the tail. No filler, no restatement 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?

An output schema exists, so return values do not need full explanation, yet the description still summarizes them. For a read-only, single-enum-param guidance tool, an agent has everything it needs to select and 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 coverage is 0% and the single 'workflow' parameter has no schema description, but the description's enumeration of eight workflows maps almost one-to-one onto the enum values (video-face-swap, image-editor, image-to-video, video-generator, lip-sync, ugc-ads, talking-photo, media-apis), effectively compensating for the missing schema text.

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 ('Read Magic Hour workflow guidance') and enumerates the covered domains (face swap, image editing, image-to-video, lip sync, UGC ads, talking photos, API integration). This clearly separates it from the many sibling *_create_* tools that actually generate media.

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 implies this is a planning/discovery step by listing the workflows it covers and explicitly stating it 'does not generate media, spend credits or check account access', which frames when it is appropriate. It never explicitly says 'call this before X create tool' or names a sibling, so it falls short of full when/when-not/alternative routing.

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