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

With no annotations, the description must carry the full behavioral burden; it does disclose the key async trait (returns job_id immediately, assets via get_job) and that two variants are produced. It omits cost/credit implications (relevant given get_balance and list_pricing siblings) and any moderation or rights-enforcement behavior beyond what the schema already says.

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 tightly packed sentences: output spec first, async retrieval contract second. No filler, and the most decision-relevant facts are front-loaded.

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 3-param async tool with no output schema, it covers what is produced, at what size, and how to retrieve it, which is most of what an agent needs. The gap is the undocumented headline parameter and no hint about cost or failure modes.

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 67%: prompt and owns_rights are documented, but headline is undocumented in the schema and the description says nothing about it either. The description adds only the fixed dimension context, not meaning for any parameter, so the baseline 3 fits.

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 (Generate) and resource (two wide X banner variants) with exact output dimensions 1536x512 (3:1 / 1500x500 class), which cleanly separates it from the generic generate_image sibling. An agent knows precisely what artifact this produces without opening the schema.

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?

It gives a clear follow-up workflow ('poll get_job for assets') but never states when to choose this over generate_image or the other kit tools, nor any prerequisites beyond the schema. Usage is implied by the fixed banner format rather than explicitly contrasted with alternatives.

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