Artificial Intelligence
18 distinct extensions were invented to do this job. Each one is a provider deciding OpenAPI would not carry something and building their own way through. Where a job has many names and few uses each, nobody won — the problem was solved privately, over and over.
18 extensions
524 occurrences
2 vendor-named
The extensions
| Extension | What it appears to do | Uses | Providers |
|---|---|---|---|
| x-mcp-group | `x-mcp-group` appears on path items. Its value is a list. Used by a single provider across 37 OpenAPI documents. Consistent with artificial intelligence — this is inferred from where the key appears a | 342 | 1 |
| x-mcp | `x-mcp` appears on operations. Its value is a structured object. Used by 3 providers across 3 OpenAPI documents. Consistent with artificial intelligence — this is inferred from where the key appears a | 71 | 3 |
| x-mcp-tool | `x-mcp-tool` appears on operations. Its value is a boolean flag. Used by a single provider across 1 OpenAPI document. Consistent with artificial intelligence — this is inferred from where the key appe | 37 | 1 |
| x-tool-description | `x-tool-description` appears on operations. Its value is a string. Used by a single provider across 1 OpenAPI document. Observed values include `Retrieves paginated active deals with filtering by owne | 27 | 1 |
|
x-ctctmcp-allow
vendor |
`x-ctctmcp-allow` appears on operations. Its value is a boolean flag. Used by a single provider across 1 OpenAPI document. It sits in the `x-ctctmcp-` namespace, so its meaning is defined by ctctmcp t | 11 | 1 |
| x-customer-user-agent | `x-customer-user-agent` appears on parameter objects. Its value is a structured object. Used by 3 providers across 10 OpenAPI documents. Consistent with artificial intelligence — this is inferred from | 10 | 3 |
| x-mcp-instructions | `x-mcp-instructions` appears on operations. Its value is a string. Used by a single provider across 1 OpenAPI document. Observed values include `To create a script, specify the path (e.g., 'f/my_folde | 6 | 1 |
| x-mcp-tool-include-fields | `x-mcp-tool-include-fields` appears on operations. Its value is a list. Used by a single provider across 1 OpenAPI document. Consistent with artificial intelligence — this is inferred from where the k | 5 | 1 |
| x-mcp-tool-opaque-fields | `x-mcp-tool-opaque-fields` appears on operations. Its value is a list. Used by a single provider across 1 OpenAPI document. Consistent with artificial intelligence — this is inferred from where the ke | 4 | 1 |
| x-mcp-server | `x-mcp-server` appears in the info block and on operations. Its value is a structured object. Used by 2 providers across 2 OpenAPI documents. Consistent with artificial intelligence — this is inferred | 2 | 2 |
| x-mcp-tool-include-query-params | `x-mcp-tool-include-query-params` appears on operations. It is used as a marker with no value. Used by a single provider across 1 OpenAPI document. Consistent with artificial intelligence — this is in | 2 | 1 |
| x-agentic-access | `x-agentic-access` appears on operations. Its value is a structured object. Used by a single provider across 1 OpenAPI document. Consistent with artificial intelligence — this is inferred from where t | 1 | 1 |
|
x-ctctmcp-tool-desc
vendor |
`x-ctctmcp-tool-desc` appears on operations. Its value is a string. Used by a single provider across 1 OpenAPI document. It sits in the `x-ctctmcp-` namespace, so its meaning is defined by ctctmcp too | 1 | 1 |
| x-customer-user-agent-Param | `x-customer-user-agent-Param` appears on parameter objects. Its value is a structured object. Used by a single provider across 1 OpenAPI document. Consistent with artificial intelligence — this is inf | 1 | 1 |
| x-inference-time | `x-inference-time` appears on header objects. Its value is a structured object. Used by a single provider across 1 OpenAPI document. Consistent with artificial intelligence — this is inferred from whe | 1 | 1 |
| x-mcp-required-fields | `x-mcp-required-fields` appears on operations. Its value is a list. Used by a single provider across 1 OpenAPI document. Consistent with artificial intelligence — this is inferred from where the key a | 1 | 1 |
| x-openpolicyagent-documentation-url | `x-openpolicyagent-documentation-url` appears in the document. Its value is a string. Used by a single provider across 1 OpenAPI document. Observed values include `https://www.openpolicyagent.org/docs | 1 | 1 |
| x-prompt-tokens | `x-prompt-tokens` appears on header objects. Its value is a structured object. Used by a single provider across 1 OpenAPI document. Consistent with artificial intelligence — this is inferred from wher | 1 | 1 |
Work with this as data
Every extension here is available over the APIs.io API and to AI agents over MCP. OpenAPI Extensions is not yet its own endpoint on the v1 API. Reach it through catalog search and the tag graph, or the MCP server.
MCP server
One button, every client — Claude, Cursor, VS Code and the rest.
https://apis.io/mcp
Tools for openapi extensions
3 MCP tools reach this
apis_io_searchSTART HERE — APIs, providers and tags for one query, each with its total.resolveTurn a domain, URL or GitHub org into the provider it belongs to.find_cohortsEvery scored population of providers in the catalog.
Call it yourself
curl for this page
Search the catalog
curl "https://apis.io/api/v1/search?q=artificial-intelligence&limit=10"
Everything under a tag
curl "https://apis.io/api/v1/tags/artificial-intelligence"Discovery needs no key. Ratings and market analysis are Pro.