AI-readiness
ai-plugin.json (well-known plugin manifest)
`/.well-known/ai-plugin.json` — the original ChatGPT plugin manifest format. Largely superseded by GPTs / Custom Actions, but still referenced and parsed by some agents.
What it is
A JSON manifest at `/.well-known/ai-plugin.json` describing a site's API surface to LLM agents: name, description, auth model, OpenAPI spec URL, contact info. Introduced by OpenAI for ChatGPT plugins in March 2023; the plugins program was sunset April 2024 in favor of GPTs and Custom Actions, but the manifest format lives on as a generic well-known capability descriptor.
Why it matters
The plugin era is over, but the well-known path is still scanned by emerging agent frameworks (LangChain, LlamaIndex agents, some MCP bridges). It costs nothing to publish if you already have an OpenAPI spec, and signals `this site has a programmatic surface` to any agent that looks. Don't build a strategy around it; do ship one if you have an API.
Who it applies to
Sites with public APIs that want to be agent-discoverable.
How WQI scores it
Web Quality Index considers this standard satisfied when the supporting factor passes.
| # | Factor | Status |
|---|---|---|
| 44 | AI plugin manifest (.well-known/ai-plugin.json) | planned |
0 of 1 supporting factors are currently collected. Sites where the remaining 1 haven't been measured will show as partial or unknown on this standard until the data lands.
Related standards
- See also
- llms.txt , AI crawlers
Other references
Examples
{
"schema_version": "v1",
"name_for_human": "Acme Widgets",
"name_for_model": "acme",
"description_for_human": "Search and order Acme widgets.",
"description_for_model": "Plugin for searching and ordering widgets from Acme Corp's catalog.",
"auth": { "type": "none" },
"api": {
"type": "openapi",
"url": "https://www.acme.example/openapi.yaml"
},
"logo_url": "https://www.acme.example/logo.png",
"contact_email": "support@acme.example",
"legal_info_url": "https://www.acme.example/legal"
}Served at /.well-known/ai-plugin.json. The OpenAPI spec is the actual contract; this is the discovery shim.