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

Annotations already declare readOnlyHint=false and destructiveHint=false, so the mutation profile is known; the description only adds that it returns the project and the next step. It omits richer context the tool clearly has (the 5-credit product_url import, downstream dependency on set_creative_brief/script), leaving behavioral disclosure thin beyond annotations.

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?

Three tight sentences, front-loaded with the core action, then the input choice, then media and returns. Every clause earns its place with no 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?

For a 9-param creation tool with no output schema, the description covers the workflow (import or describe product, attach media, get project + next step) adequately, and the heavy detail lives in schema param descriptions. It stops short of noting prerequisites like ordering language/video_quality before the brief, so it is complete but not exhaustive.

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 high (78%), but the description adds real value by explaining the alternative input path — import via product_url versus supplying product_name and product_description — a relationship the schema does not state. It likewise clarifies that media accepts URL-based assets. This is meaningful semantics beyond 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?

States a specific verb+resource outcome ('Starts a new video ad for a product') that cleanly separates it from sibling readers/mutators like get_project, list_projects and set_product. An agent understands it creates and returns a new project object without needing the 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?

Clearly gives the two input pathways (product_url to import, or product_name + product_description) and tells the agent to attach media by URL, with create_media_upload named in the schema for local files. It lacks explicit when-not guidance or a 'call this first' ordering versus other setup tools, so it stops short of a 5.

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