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

Goes well beyond the annotations by disclosing runtime (2–6 minutes), real cost (~$0.053 of engine cost plus plan margin), the budget cap semantics, and the required write scope. These are exactly the operational facts an agent needs before committing to an expensive, slow, write-scoped call.

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?

Front-loaded with purpose, then duration, then routing advice, with the cost warning capitalized for salience. The output enumeration is long but every item is a distinct capability an agent would want to know about, so it earns its space.

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 expensive, slow, destructive-hinted, open-world tool with an output schema already covering return shape, the description supplies everything else: latency, cost, budget behavior, auth requirement, and the sibling workflow. Nothing material is missing.

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 baseline is 3; the description earns an extra point by framing budgetUsd as a cost ceiling and tying it to chargedUsd, giving the agent a cost-control mental model rather than just a type. It does not add syntax for the url parameter that isn't already in the schema.

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?

Specific verb ('Measure') plus resource ('a reel at a URL') with an enumeration of exactly what is extracted: cuts, spoken words with timing, captions, music, loudness, pacing, teleprompter script. It also explicitly positions itself against clone_reel, so an agent can distinguish it from siblings without opening either 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?

States when to use it in concrete terms: 'Read it before clone_reel, or to make a reel like it.' That names the alternative and the condition that selects this tool, leaving nothing to inference.

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