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

Annotations only flag it as a non-idempotent write with open-world effects; the description adds the real behavioral load: billing at cost to the user's balance, the confirm:false/true two-phase commit that spends nothing until confirmed, and the side effect that brain_note is persisted to the project's Second Brain on confirm. It also encodes a hard constraint the annotations cannot express — the model is never switched for price or balance.

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 capability and cost statement is front-loaded, then the workflow, then the invariants — a sensible ordering for a 25-parameter orchestration tool. It is long and the arrow-chain middle paragraph is dense, but for this parameter count almost every sentence carries a rule an agent would otherwise get wrong.

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 25-parameter, non-idempotent generation tool with no output schema, it covers triggering, sequencing, cost gating, input binding and post-call verification. It stops short of describing failure handling, refunds on failed generations, or latency/polling expectations beyond naming check_generation.

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 the schema already documents every field; the description goes beyond it by adding cross-parameter rules that no single field carries, notably that references and frames never mix and that video_mode is mandatory whenever kind=video. It restates some schema content (ids never URLs, brain_note format), which keeps it from a 5.

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 first sentence names a specific verb (make) and enumerates the exact outputs (image, video clip, instrumental track, voiceover, upscale) plus the billing model. It explicitly separates itself from combine_videos for joining clips, so an agent can route correctly without opening any 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 provides an explicit ordered workflow with named sibling calls (load_skill → get_emero_brain → generate → check_generation), and states the when-nots: one generation per request, clips get joined with combine_videos, references and frames never mix. Alternatives and exclusions are both spelled out.

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