Look up vehicle data by Year, Make, and Model using the CarsXE YMM API. Use this when a user doesn't have a VIN but knows the year, make, and model of a vehicle and wants specs, trims, or features.
SkillScore61Maintained
Automatic
◆Research pack
Last verified 9/1/2026
What it changes
Passed 13 of 21 test cases with the skill, and 4 of 21 without it.
Without skill17%
With skill61%
Checks it passed that the model alone missed
Refers to AGENTS.md
Omits the trim parameter from the URL
Queries https://api.carsxe.com/v1/ymm
and 15 more in the full report
10 fixed4 passed either way9 still failing0 broke
Pass-rate lift
+43 pp
Tokens
+3%
Agent turns
0%
Response time
+8%
Model gemini-3.6-flashMeasured 9/1/2026v114 of 23 cases passed with skill · 21 comparable
Tokens, turns and time describe resource use, not a dollar price.
See it in action
One of 10 test cases the skill fixed. Same model, same prompt, with and without the skill.
1 of 10
Prompt
What HTTP method should be used when sending a year-make-model query for a 2018 Hyundai Elantra to the CarsXE endpoint?
What was checked, without and with the skill
Checked
Without skill
With skill
Specifies the GET HTTP method
Passed
Passed
Targets the URL https://api.carsxe.com/v1/ymm
Missed
Passed
case-14 · gemini-3.6-flash · 9/1/2026 · answers are capped and redacted
What's inside
The instructions your model reads when the skill loads.
SKILL.md10 linessingle file
When the user asks about a vehicle by year, make, and model (without a VIN):
Make an HTTP GET request to the CarsXE YMM API:
GET https://api.carsxe.com/v1/ymm?key={CARSXE_API_KEY}&year={YEAR}&make={MAKE}&model={MODEL}&source=codex_plugin[&trim={TRIM}]
Only include trim if the user specified one.
Present available trims, engine options, features, and specs.
If the user didn't specify a trim, list all available trims for that year/make/model.
If the API key is missing, tell the user to set the CARSXE_API_KEY environment variable (see AGENTS.md).