deepseek-harness/packages/web/web-search-exa/README.md

# @deepseek-ai/dsh-web-search-exa

An [Exa](https://exa.ai)-backed `WebSearchProvider` for the harness [web capability seam](../web/README.md) (`ctx.web`). It calls Exa's `POST /search` endpoint with highlight contents and maps the flat `results[]` into the seam's normalized `WebSearchResult`.

This is an **implementation** package: it registers a provider into `ctx.web`, it does not own the `ctx.web` key and it does not register a model-facing tool (that is `@deepseek-ai/dsh-tool-web`). Like `@deepseek-ai/dsh-llm-deepseek`, it is a function/namespace plugin (`inject: ['web']`) that registers its backend, not a default-export service.

## Model Experience

| Context surface | What the model sees | Token effect |
|---|---|---|
| Web search result, indirectly | Through `dsh-tool-web`, the conversation model sees Exa result URLs, titles, first highlight snippets, and publication dates. No generated answer or provider-private response fields enter the tool result. | Zero direct harness-model tokens. Result size scales with the bounded source list and snippets; the seam enforces `maxResults`, and retained results remain until compaction. |

## Config

| Key | Default | Meaning |
|---|---|---|
| `apiKey` | `$EXA_API_KEY` | Exa API key. Empty/absent → provider `status()` reports `missing-credential` (the seam reports `configured-unavailable`/`none`). |
| `baseURL` | `https://api.exa.ai` | Endpoint base; `/search` is appended. An unparseable value makes `status()` report `misconfigured`. |
| `searchType` | `auto` | Retrieval mode sent as Exa's `type`: `auto` (Exa decides), `keyword`, or `neural`. |
| `numResults` | (unset) | Default result count when a request carries no `maxResults`. Unset sends no default. Must be a positive integer. |
| `highlightsPerResult` | `1` | Highlight sentences requested per result (Exa's `highlightsPerUrl`). Must be a positive integer. |

```yaml
- id: web-search-exa
  name: '@deepseek-ai/dsh-web-search-exa'
  config:
    apiKey: !!js process.env.EXA_API_KEY
```

## Mapping

Exa returns a flat `results[]` and no generated answer, so `content` is omitted. Each result maps to a `WebSearchSource`: `url` ← `url`, `title` ← `title`, `snippet` ← the first non-empty `highlights[]` entry (a result with no highlight has no portable snippet and is dropped), `publishedAt` ← `publishedDate`. A request's `maxResults` wins over the configured `numResults` default and is sent as Exa's `numResults` for a cost/latency optimization; the final bound is enforced by the seam. Provider failures (HTTP errors, network failure, unparseable or wrong-shape bodies) surface as `WebError` `WEB_PROVIDER_ERROR`; an aborted request surfaces as `WEB_ABORTED`.

## Known Limitations and Deferred Work

- **A result with no non-blank highlight is dropped entirely** — no portable snippet to map, so fewer sources than the requested count can return.
- **Only `searchType`/`numResults`/`highlightsPerResult` are exposed** — Exa's other controls (livecrawl, category, domain/date filters, full-text contents) wait on provider-neutral seam fields ([seam RFC](../../../docs/rfc/implemented/architecture/2026-06-24-web-capability-seam.md)).
- **Abort classification is error-shape-based** — only a `DOMException` named `AbortError` maps to `WEB_ABORTED`; an abort carrying a custom reason (e.g. `dsh-timeout`'s `TimeoutReason`) surfaces as `WEB_PROVIDER_ERROR`.