> ## Documentation Index
> Fetch the complete documentation index at: https://aisa.one/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# Exa Answer

> Ask a question and get a written answer with citations.

Ask a question and get a written answer with citations. `query` is required; `text` includes the source text and `outputSchema` shapes a structured reply. Returns `requestId`, `answer` as prose, `citations[]` with `id`, `title` and `url`, and `costDollars`. Measured at 2.1 seconds with 8 citations. Billed at a flat rate per successful request. It sits between a search and a research run: faster and cheaper than [`post_exa_agent_runs`](/docs/api-reference/search/post_exa-agent-runs), and more direct than reading [`post_exa_search`](/docs/api-reference/search/post_exa-search) results yourself. [`post_perplexity_sonar`](/docs/api-reference/perplexity/post_perplexity-sonar) answers the same shape of question — reach for Exa when the retrieval needs to be semantic.

<Note>
  **First time?** Point any MCP client at `https://mcp.aisa.one/mcp` — Claude
  Code, Codex, Cursor, VS Code and the rest. Authorization is OAuth: the client
  opens a browser, you click Allow once, and there is no key to paste. The
  commands per client, and what each call costs, are on
  [aisa.one/mcp](https://aisa.one/mcp#connect).
</Note>

[Set this endpoint up in your agent →](https://aisa.one/mcp?from=/api-reference/search/post_exa-answer)


## OpenAPI

````yaml openapi/exa.json POST /exa/answer
openapi: 3.0.0
info:
  title: Exa API
  version: 1.0.0
  description: >-
    Unified API documentation for Exa neural semantic search endpoints exposed
    through the AIsa gateway: Search, Contents, Answer, and the asynchronous
    research Agent Runs.


    Search, Contents, and Answer are synchronous and billed at a flat rate per
    successful request. Agent Runs is asynchronous: the caller submits a run and
    then polls the returned job resource for status and results, billed at a
    flat rate per run. Upstream 4xx responses (for example 401/403/404) are not
    billed. The `costDollars` field that Exa returns is the upstream cost
    breakdown and is informational only — customer billing follows the flat AIsa
    prices above.
servers:
  - url: https://api.aisa.one/apis/v1
security:
  - bearerAuth: []
paths:
  /exa/answer:
    post:
      tags:
        - https://docs.exa.ai/reference/answer
      summary: Get a direct, cited answer to a question.
      description: >-
        Ask a question and get a written answer with citations. `query` is
        required; `text` includes the source text and `outputSchema` shapes a
        structured reply. Returns `requestId`, `answer` as prose, `citations[]`
        with `id`, `title` and `url`, and `costDollars`. Measured at 2.1 seconds
        with 8 citations. Billed at a flat rate per successful request. It sits
        between a search and a research run: faster and cheaper than
        `post_exa_agent_runs`, and more direct than reading `post_exa_search`
        results yourself. `post_perplexity_sonar` answers the same shape of
        question — reach for Exa when the retrieval needs to be semantic.
      operationId: post_exa_answer
      requestBody:
        required: true
        content:
          application/json:
            schema:
              type: object
              properties:
                query:
                  type: string
                  description: The question to answer.
                  example: >-
                    Which manufacturers had the top three global EV sales in
                    2025?
                text:
                  type: boolean
                  description: Include the full page text of each citation.
                type:
                  type: string
                  enum:
                    - auto
                    - fast
                    - instant
                    - deep-lite
                    - deep
                    - deep-reasoning
                  description: Retrieval mode used to gather sources before answering.
                outputSchema:
                  type: object
                  description: JSON Schema for a structured answer output.
              required:
                - query
      responses:
        '200':
          description: Answer generated successfully.
          content:
            application/json:
              schema:
                type: object
                properties:
                  requestId:
                    type: string
                  answer:
                    description: >-
                      The generated answer. A string, or a structured object
                      when outputSchema was supplied.
                    nullable: true
                  citations:
                    type: array
                    description: Sources supporting the answer.
                    items:
                      type: object
                      properties:
                        id:
                          type: string
                        url:
                          type: string
                        title:
                          type: string
                        author:
                          type: string
                        publishedDate:
                          type: string
                        text:
                          type: string
                  costDollars:
                    description: >-
                      Upstream Exa cost breakdown. Informational only; customer
                      billing is a flat per-request rate.
                    nullable: true
components:
  securitySchemes:
    bearerAuth:
      type: http
      scheme: bearer

````

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