API Discovery Service

Name: API Discovery Service API
Brand: API Discovery Service
Availability: InStock

✓ Official Vendor SpecDeveloper ToolsPackage Registrynone2 EndpointsREST

For Agents

Enumerate every Google API and fetch its machine-readable description so tools, SDKs, and agents can self-bootstrap.

Quickstart

Get started with API Discovery Service in minutes using your preferred integration method.

# Add to your MCP client config (Claude Desktop, Cursor, Windsurf)
{
  "jentic": {
    "url": "https://api.jentic.com/mcp",
    "auth": "oauth"
  }
}

# Then ask your agent:
"list all Google APIs"

# → Jentic returns the GET /events tool with parameter schema, agent executes.

Capabilities

What an agent can do with API Discovery Service API.

List the directory of all Google APIs available through Discovery

Fetch the full Discovery REST description for any Google API and version

Extract method definitions, parameters, and request/response schemas for SDK generation

Resolve OAuth scopes and base URLs declared by a target API

GET STARTED

Start building with API Discovery Service API

Explore with Jentic

View OpenAPI Document

Use Cases

Patterns agents use API Discovery Service API for, with concrete tasks.

★ SDK and Client Library Generation

Tooling teams call /apis to discover every Google API, then /apis/{api}/{version}/rest to pull the Discovery document for each. The descriptions feed code generators that emit typed clients in Python, Go, Java, and TypeScript. This is exactly how the official Google API Client Libraries are produced.

Call /apis with preferred=true, then for the calendar v3 entry call /apis/calendar/v3/rest and extract every method's id, path, and parameter schema.

Scope and Permission Inventory

Security and platform teams use the Discovery API to inventory every OAuth scope declared by every Google API in a project's footprint. Pulling the full directory and extracting auth.oauth2.scopes from each Discovery doc gives a complete map of what tokens can do — useful for least-privilege reviews and risk register updates.

Call /apis with preferred=true and for each entry fetch /apis/{api}/{version}/rest, extract auth.oauth2.scopes, then return a deduplicated scope list.

Spec-Driven Integration Bootstrapping

Integration platforms (including Jentic) use Discovery as the source-of-truth for converting Google APIs into modern OpenAPI specs. Pulling /apis once on schedule produces the directory; pulling per-API REST documents produces the operational shape; conversion logic translates that into OpenAPI 3.x for tooling and agent runtimes.

Fetch /apis/drive/v3/rest, then transform the returned Discovery REST document into an OpenAPI 3 paths object preserving operationId, parameters, and request/response schemas.

Agent-Driven API Lookup

Through Jentic, an AI agent that needs to operate on a Google API it has not seen before can call the Discovery service to fetch the description on demand, then use it to build a request — all without OAuth, since Discovery is unauthenticated.

Use Jentic to search 'list Google APIs', load the schema for /apis, and execute it with preferred=true to enumerate the catalogue.

Key Endpoints

2 endpoints — google's api discovery service is the meta-api that describes every other google api.

METHOD

PATH

DESCRIPTION

GET

/apis

List the directory of Google APIs

GET

/apis/{api}/{version}/rest

Fetch the Discovery REST document for a specific API and version

GET

/apis

List the directory of Google APIs

GET

/apis/{api}/{version}/rest

Fetch the Discovery REST document for a specific API and version

Why though Jentic?

Three things that make agents converge on Jentic-routed access.

Credential isolation

Unauthenticated API — no credentials are stored or rotated. Jentic still executes the call from an isolated runner per agent session so response data is contained.

Intent-based discovery

Agents search by intent (e.g., 'list Google APIs' or 'fetch Calendar API spec') and Jentic returns the right Discovery operation with its parameter schema.

Time to first call

Direct integration: under an hour to call two unauthenticated endpoints and parse JSON. Through Jentic: minutes — search, load schema, execute.

Related APIs

Alternatives and complements available in the Jentic catalogue.

Complementary

Service Usage API

Enable and disable Google APIs for a project — pairs with Discovery's enumeration

Use Discovery to find which APIs exist; use Service Usage to enable them on a target Google Cloud project.

Complementary

Service Management API

Manage service configurations for Google-managed APIs

Use Service Management to operate on managed services; use Discovery to read the user-facing API surface.

Alternative

Service Control API

Runtime check and report calls for service consumers — different concern from Discovery's surface description

Choose Service Control for runtime quota and access checks on Google-managed services; choose Discovery to read the user-facing API surface.

FAQs

Specific to using API Discovery Service API through Jentic.

What authentication does the Google API Discovery Service use?

None. Both /apis and /apis/{api}/{version}/rest are public, unauthenticated GETs. Through Jentic, the call runs in the sandboxed runner without any vault credentials touching the request.

Can I get the OAuth scopes for any Google API through Discovery?

Yes. Fetch /apis/{api}/{version}/rest and read auth.oauth2.scopes — every scope the API declares is listed there with its description, which is the canonical source for least-privilege OAuth setup.

What are the rate limits for the API Discovery Service?

Google does not publish strict per-second limits for Discovery, but unreasonable polling can be throttled. Cache responses locally and re-fetch on a slow cadence (daily for the directory, weekly per-API) instead of calling on every request.

How do I list every Google API through Jentic?

Search 'list Google APIs', load the schema for /apis, then execute it. To filter to the recommended version of each API, pass preferred=true in the query parameters.

Is the Discovery REST format the same as OpenAPI?

No. Discovery is Google's own format that pre-dates OpenAPI 3. It contains similar concepts (resources, methods, parameters, schemas) but uses different field names and structures. Tools convert it to OpenAPI for compatibility with modern toolchains.

Is the Discovery Service free?

Yes. There is no charge for Discovery calls and you do not need an API key or OAuth token to read the directory or any individual Discovery REST document.