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

Annotations already declare this is a non-read-only, non-destructive, non-idempotent, closed-world mutation, so safety is covered. The description usefully explains what each boolean value selects, but it does not clarify whether the setting is account-wide or per-post, whether it affects existing posts or only future ones, or that re-calling it overwrites the prior choice.

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?

A single, front-loaded sentence that conveys the setting and both value meanings without filler. Nothing is wasted and the point arrives immediately.

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 one-parameter boolean preference tool with annotations covering the safety profile and no output schema to explain, the description is nearly sufficient. The only gap is the scope of the change (global vs. per-post, retroactive or not), which is minor given the tool's simplicity.

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 100%, the schema already documents useAiImages as 'true = AI-created images, false = real photos.' The description restates this mapping in nearly identical terms, adding no syntax or edge-case meaning beyond the schema, so the baseline of 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?

The description states a specific setting verb ('Choose whether') and its resource (AI-created vs. real images for the user's posts), making the tool's purpose immediately clear. It does not name or contrast with any sibling, but the toggle semantics are distinct enough to stand alone.

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?

There is no guidance on when this tool should be invoked, what context triggers it, or how it differs from related tools like use_character_reference or select_brand_images. The agent must infer usage entirely from the setting semantics.

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