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

With no annotations provided, the description carries the full behavioral burden and does so admirably. It discloses the mutation (starts a render), the side effect (spends user's credits), the async pattern (returns id immediately, poll later), and the auth prerequisite (needs API key) — all beyond what the schema conveys.

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 dense sentences with zero waste. The main action is front-loaded, followed by the async pattern and the credit/auth caveat. Every clause earns its place.

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 no-annotation, no-output-schema tool with a nested object, the description covers the essentials: invocation, async result retrieval, side effects, and auth. It lacks error-case handling (e.g., missing/invalid API key) and the animate distinction, but these are minor gaps against an otherwise strong definition.

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%, so all three parameters (image_url, prompt_id, text_variables) are fully documented in the schema. The description adds no parameter-level detail beyond what the schema already provides, so the baseline 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 verb and resource — 'Run a PromptFrenzy prompt on the user's account and start a render' — which clearly defines the tool's function. It also distinguishes itself from the get_generation sibling by noting it returns an id immediately and that polling is needed for results.

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 provides implicit usage guidance: it routes to get_generation for results and implies credit cost is a consideration. However, it doesn't explicitly say when NOT to use this tool or how it compares to animate (the closest sibling), leaving the selection logic partially to inference.

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