How does ChatGPT decide which plugin to use?
For plugins a user has installed, OpenAI says ChatGPT decides when to call a tool from the metadata the developer provides: names, descriptions and parameter notes. A user can also pick a plugin by name with an @ mention. For plugins the user has not installed, OpenAI publishes two criteria, utility and user satisfaction, and no mechanism. The two cases are different problems and should be measured apart.
Two cases, two answers
Each point carries the page it came from. Platform behaviour is described in OpenAI's own words where we can.
The Help Center says ChatGPT automatically uses installed plugins when they are relevant to the request. The metadata guide says ChatGPT and Codex decide when to call a tool based on the metadata the developer provides.
OpenAI, Help Center, Plugins in ChatGPT · OpenAI, Developer docs, optimize metadata
A user can select a plugin directly with an @ mention or from the composer, which skips the choice altogether.
OpenAI, Help Center, Plugins in ChatGPT
Suggestions go to plugins OpenAI selects for enhanced distribution. The stated criteria are strong utility in real use and high user satisfaction. No signals or weights are published.
OpenAI, Developer docs, publish and review
Plugin text must not instruct the model to prefer one plugin over others or interfere with fair discovery. Wording that tries to game the choice breaks the guidelines.
OpenAI, Developer docs, plugin guidelines
What we do not know
- OpenAI does not say how ChatGPT chooses between two installed plugins that could both do the job.
- Nobody outside OpenAI knows the full recommendation method. Lists of ranking factors published by agencies are their own inference.
Nobody outside OpenAI knows the full recommendation method. We report what is documented, what we counted, and what is still unknown, and we keep the three apart.
Sources and dates
Source date is the date on the source itself. Checked is the day we last read it.
| Source | Publisher | Source date | Checked |
|---|---|---|---|
| Help Center, Plugins in ChatGPT | OpenAI | Updated early Oct 2026 | 9 Oct 2026 |
| Developer docs, optimize metadata | OpenAI | Not dated | 9 Oct 2026 |
| Developer docs, publish and review | OpenAI | Not dated | 9 Oct 2026 |
| Developer docs, plugin guidelines | OpenAI | Not dated | 9 Oct 2026 |
Related: Do descriptions affect discovery? · How to measure plugin visibility · ChatGPT plugins research hub
- 9 Oct 2026: answer published, from OpenAI pages read at the source that day.
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