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

Annotations only say it is a non-destructive, non-read-only, closed-world call. The description adds real behavioral context: the render is async ('hands back a job at once'), takes minutes for long edits, is cancellable via cancel_job, and its result is retrievable through job_status with an id and download link.

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 the action and the async behavior, and the parenthetical about export duration earns its place. The sentence about Cardboard's card playing the newest preview/export is slightly tangential but still aids discovery.

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?

With no output schema, the description usefully explains what job_status returns (export id and file link). It covers lifecycle well, but for a 5-parameter export tool it leaves the output-quality parameters completely unexplained.

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 only 20% (just 'project'), yet the description says nothing about format, quality, frameRate, or resolution — no defaults, no note about what happens when they're omitted. The enums are self-describing but the agent gets no guidance on choosing values.

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?

States a specific verb and resource ('Render the project in Cardboard's export pool') plus the source of truth ('from the originals in Cardboard's storage'), which separates it from AI-generation siblings like generate_video. It also explicitly names what it is not (look, verify_timeline for checking an edit).

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?

Explicit selection guidance: 'For when the user wants the file; check an edit with look and verify_timeline instead.' It names the alternative tools and the condition that routes to them, plus points to job_status for following the render.

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