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

Adds substantial context beyond annotations: credit spend is charged from the personal wallet only when the breakdown is saved, priced by length band, cached ads are free, the call blocks ~45 s and may return status 'pending', and there is a hard input limit of ~3 minutes. This reconciles the non-read-only, idempotent hints with real billing semantics.

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 verb and deliverable, then cost, then the pending/alternative workflow — a sensible order. It is dense and reads as one long run-on, with the credit rules packed into a single unwieldy sentence, so a little structure is lost but nothing is redundant.

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 carries the return-value burden and does so thoroughly (each output artifact, the public page link, the credits field, and the 'pending' status with its follow-up call). Length limits, cost, and handoff to cinematic_ads_guide are all covered.

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% for the two parameters, so the baseline is 3. The description does add useful accepted-source context for 'url' (TikTok, Instagram, Facebook/Shorts, YouTube, Meta Ad Library, TikTok Creative Center, public .mp4) plus the ~3 minute cap, but it never mentions the optional 'video_url' parameter, leaving that half of the parameter surface to the schema alone.

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 ('Break down a video ad') and enumerates the concrete artifacts returned: formula, hook, message, CTA, pacing, per-scene timings/jobs, remake tips, creative brief, script template, and public page link. It is clearly distinguishable from ad_breakdown_get (retrieval) and cinematic_ads_guide (remaking), which it names.

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 explicit routing conditions: use ad_breakdown_get when status is 'pending', use cinematic_ads_guide to remake for the brand, and 'Ask the user before breaking down a new ad.' It also states the cost-free case (an ad already broken down by anyone) versus the paid case, so the agent knows when to spend.

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