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

Goes well beyond the readOnly/idempotent annotations by disclosing empty-state semantics ("An empty `ideas` list means the series ships none"), the 404 case, and hard presentation constraints (offer at most 3, one line each, end with 'or tell me yours', never paste full text). Some phrasing such as "Free, instant, creates nothing" restates what the annotations already declare, which keeps it from a 5.

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?

Purpose is front-loaded, but the body is a dense run-on mixing usage rules, output formatting, downstream constraints, and empty-state handling, with heavy all-caps emphasis. Most clauses earn their place, yet the `idea` paragraph belongs to a different tool and dilutes this one.

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 covers return semantics (a list of preset cards, brevity of items, empty-list meaning) plus the 404 error. What it lacks is any indication of item structure beyond "one line each," but that is a minor gap for such a narrow read.

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% and there is only one parameter, so the schema already carries the load; the description only adds the 404-means-unknown-id behavior. It also discusses an `idea` value that is not a parameter of this tool, which could momentarily confuse an agent mapping arguments.

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 with scope precision: "Returns ONE series' CURATED preset ideas (the authored cards the webapp shows on its idea step)." It also explicitly distinguishes itself from the sibling path an agent would otherwise take, naming generate_story_video and the default invent-your-own behavior.

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?

Gives an explicit when-not ("THIS IS NOT THE DEFAULT WAY TO GET AN IDEA: invent three of your own") and a narrow when ("call this only when the user asks what the SERIES itself suggests"), including a sample user utterance. It also lists the follow-up behavior after the call, so the agent knows the whole workflow, not just the trigger.

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