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

Annotations are all false, so the description carries the burden. It adds meaningful behavioral context: 'deterministic template render, no planner' and 'Returns run ids — poll get_run for status' reveal an asynchronous, run-based execution model. It doesn't contradict annotations, though it doesn't disclose potential side effects or costs.

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?

The description is dense and efficient: three sentences deliver purpose, usage guidance, item structure, and post-call behavior. Every sentence earns its place, and the most important scoping guidance is 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 an advanced tool with zero schema descriptions, the description covers the key context: what inputs are expected, when to prefer an alternative, and what to do with the returned run ids. The only minor gap is the lack of detail on how to construct seed_body and the optional 'name' parameter, but the term 'pre-formed' reduces the agent's responsibility.

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 description coverage is 0%, but the description compensates by enumerating the expected per-item fields: output_type, channel, seed_body, archetype?, family?, surface?, caption?, voice_id?. This gives meaning beyond the generic 'additionalProperties: true' schema, though the optional 'name' parameter is not mentioned and individual field semantics are left to inference.

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 clearly states the tool renders pre-formed SirenSeed bodies directly with a deterministic template render and no planner. It identifies the specific resource and operation, and differentiates from sibling tools like create_campaign by emphasizing the 'direct' advanced path.

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 explicitly instructs the agent to prefer create_campaign unless the user has concrete seed JSON, which is a precise when-to-use rule. It also directs the agent to poll get_run after receiving run ids, providing clear follow-up guidance.

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