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

Much of the added context is genuinely helpful and consistent with annotations (keeping originals matches destructiveHint=false; 'no generation or charge' clarifies write-but-not-generate). However, 'Idempotency key required' describes exactly-once/de-duplicated semantics, which conflicts with the declared idempotentHint=false — a caller could reasonably expect a repeated call with the same key to be a no-op, while the annotation says otherwise.

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 core purpose is front-loaded and most sentences carry non-obvious information. But the trailing 'Arguments: {...}' block merely restates the input schema (no credit for repeating structured data), and the ordering jumps between rights, duration, playback and argument shape.

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 nested-parameter write tool with 0% schema coverage and no output schema, the description covers a lot (idempotency, rights timing, voice classification, playback path). Still missing are what path.id refers to, what version/consent control, and whether the call returns an asset id synchronously or a job to poll.

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%, and the description adds meaning for asset_ids (2–12, order), idempotency_key (required), and the use_as_voice/person_id pairing plus the 60-second total rule. It leaves path.id (which resource identifier?), version, and consent unexplained, which is a real gap for a write tool.

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 opening sentence gives a precise verb, resource and constraints ('Concatenate 2–12 owned audio assets in asset_ids order, keeping every sample and the originals'), which is clearly distinct from generation siblings like kelpo_generate. It never explicitly names the alternative to pick instead, so sibling differentiation is implicit rather than stated.

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?

Useful preconditions are spelled out: idempotency key required, new voice references need 60 seconds TOTAL, rights are confirmed only before generation, and the result is consumed via get_asset/asset_download. There are no explicit when-not-to-use statements or named alternatives, so it stops short of full routing guidance.

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