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

Annotations already declare readOnlyHint/idempotentHint/destructiveHint=false, so safety needs no restating. The description adds value beyond them: "Free" discloses cost, and "the minimum fields the server checks" reveals that downstream validation will reject under-specified prompts. It stops short of saying what the returned guide looks like.

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?

Front-loaded with purpose, then the enum inventory, then the call to action — a sensible order with little waste. The one-word "Free." fragment and the long run-on enumeration sentence slightly hurt readability.

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 single-required-enum reference tool with no output schema, the description covers what the guide contains (how to write the prompt plus the server's minimum fields), which tool should be called next, and how to choose the enum. There is nothing an agent needs to invoke it correctly that is missing.

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 100% and the schema's own text is only "The engine and type of shot." The description expands every enum value with engine and input modality (h3_clip: text or photo → video; wan_clip: still camera; image_product: always from a real product photo), which the schema does not convey.

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 resource (a prompt-writing guide) scoped to one engine/shot type, and enumerates all seven supported types with one-line characterizations. It is clearly a lookup/reference tool, unmistakable from siblings like generate_image or generate_video which consume it.

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?

"Read it before writing a prompt for generate_image, generate_video or Ignix Creator, and follow it" gives explicit when-to-use and names the tools it serves. It also supplies a selection heuristic (product → image_product; only a place → place; person/`who` → image_people; else image_scene), though it never states an exclusion case such as when the guide is unnecessary.

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