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

Annotations only give coarse hints (destructiveHint, non-idempotent); the description adds real context: the copy lands at script review free of charge, scenes can be deleted but not added, reference photos cannot be applied to a copy, and single_scene renders immediately and spends credits. That is exactly the non-obvious behavior an agent needs before calling a mutating tool.

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 core action, then the post-copy workflow, then the exclusions/expensive mode. Every sentence carries an actionable constraint (free vs credits, delete-not-add, rewrite-before-approve) rather than filler.

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 still notes that edit_scene 'result lists the scenes', and it covers the full lifecycle of a copy (create, rewrite, approve) plus the alternative path. Nothing an agent needs to invoke it correctly appears 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 baseline is 3; the description nonetheless adds provenance for template_job_id (it comes from list_templates) and reiterates the credit cost of single_scene. product_id semantics are left to the schema, which already documents list_catalog sourcing and defaults.

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 concrete verb+resource ('Copy a template from list_templates ... into the user's account') and names the sibling that supplies the input. It also differentiates itself from create_video by stating the copy is word-for-word the template's subject.

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?

Explicitly routes the agent: use this tool to copy a template, use create_video when the video must show the user's own person or product photos, and call edit_scene before approve_script. The single_scene=True case is called out with its cost implication, giving clear when/when-not selection rules.

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