---
id: agent-api-authentication-schemes-and-bearer-tokens
title: 'Agent API Authentication Schemes and Bearer Tokens'
schema_type: TechArticle
category: ai
language: en
confidence: medium
last_verified: '2026-06-02'
created_date: '2026-06-02'
generation_method: ai_structured
derived_from_human_seed: true
conflict_of_interest: none_declared
is_live_document: false
data_period: static
atomic_facts:
  - id: fact-ai-agent-api-authentication-schemes-and-bearer-tokens-1
    statement: >-
      Stripe API documentation describes authentication with API keys and HTTP Basic Auth.
    source_title: Stripe API Authentication
    source_url: https://docs.stripe.com/api/authentication
    confidence: medium
  - id: fact-ai-agent-api-authentication-schemes-and-bearer-tokens-2
    statement: >-
      Google Cloud documentation describes authentication as determining the identity of a
      client.
    source_title: Google Cloud Authentication
    source_url: https://docs.cloud.google.com/docs/authentication
    confidence: medium
  - id: fact-ai-agent-api-authentication-schemes-and-bearer-tokens-3
    statement: >-
      The OpenAPI Specification defines a Security Scheme Object for authentication and
      authorization schemes.
    source_title: OpenAPI Security Scheme Object
    source_url: https://spec.openapis.org/oas/v3.1.0#security-scheme-object
    confidence: medium
completeness: 0.83
known_gaps:
  - Authentication behavior depends on token type, scope, expiry, rotation, audience, transport security, SDK defaults, and whether credentials are safe for browser-side use.
disputed_statements: []
primary_sources:
  - title: Stripe API Authentication
    type: documentation
    year: 2026
    url: https://docs.stripe.com/api/authentication
    institution: Stripe
  - title: Google Cloud Authentication
    type: documentation
    year: 2026
    url: https://docs.cloud.google.com/docs/authentication
    institution: Google Cloud
  - title: OpenAPI Security Scheme Object
    type: standard
    year: 2026
    url: https://spec.openapis.org/oas/v3.1.0#security-scheme-object
    institution: OpenAPI Initiative
secondary_sources: []
updated: '2026-06-02'
ai_models:
  - gpt-5-codex
---

## TL;DR

Authentication scheme metadata tells agents how to call an API without leaking, misplacing, or over-scoping credentials.

## Core Explanation

Agents should identify the authentication scheme before making requests. API keys, bearer tokens, Basic Auth, OAuth tokens, and signed requests have different placement, expiry, and security rules. A token that is safe on a server may be unsafe in browser-executed code.

Useful evidence includes the required header, token format, scope, audience, expiry, allowed origins, and whether the API's OpenAPI document exposes a security scheme. Agents should avoid guessing from one successful request because providers may use multiple schemes across endpoints.

## Source-Mapped Facts

- Stripe API documentation describes authentication with API keys and HTTP Basic Auth. ([source](https://docs.stripe.com/api/authentication))
- Google Cloud documentation describes authentication as determining the identity of a client. ([source](https://docs.cloud.google.com/docs/authentication))
- The OpenAPI Specification defines a Security Scheme Object for authentication and authorization schemes. ([source](https://spec.openapis.org/oas/v3.1.0#security-scheme-object))

## Further Reading

- [Stripe API Authentication](https://docs.stripe.com/api/authentication)
- [Google Cloud Authentication](https://docs.cloud.google.com/docs/authentication)
- [OpenAPI Security Scheme Object](https://spec.openapis.org/oas/v3.1.0#security-scheme-object)