# Elasticsearch (slim)

> Elasticsearch is Elastic's search engine and vector database, with keyword, vector and hybrid search over a REST API. Agents reach it through that API or the Agent Builder MCP server on Elastic Cloud and Elastic Stack 9.2 or later.

- Full: https://www.anchorterminal.com/tools/elasticsearch.md (~7,750 tokens) · this version ~2,030 tokens · JSON https://www.anchorterminal.com/tools/elasticsearch.json · canonical https://www.anchorterminal.com/tools/elasticsearch
- Index: https://www.anchorterminal.com/llms.txt · API: https://www.anchorterminal.com/api/v1/index.json · Updated: 2026-10-09

**B · 67.7/100 · rank #224 of 842 · #6 in Retrieval & vector search · not agent-ready · confidence medium**


Assessment: Keyword, dense and sparse vector, and hybrid search with rank fusion sit behind one OpenAPI-described REST API, with API keys scoped to indices and privileges. The status page lists more than 20 incidents marked major since July 2026, and Elasticsearch 9.5.0 returned incorrect results for some queries without raising an error.

## Facts

- Kind: HTTP API · vendor: Elastic · category: Retrieval & vector search · legal entity: Elasticsearch B.V. · provenance 71/100
- Local only (HTTP): npm `@elastic/elasticsearch`, pypi `elasticsearch`
- Auth: OAuth or key · pricing: Pay per use · x402: no · licence: AGPL-3.0, SSPL-1.0 or Elastic Licence 2.0 at the user's choice for most source. The `x-pack` folder is under Elastic Licence 2.0 only. Elastic Cloud is a proprietary service under Elastic's terms
- Probe metrics: not measured yet (probes haven't run)
- Surface graded: Elastic Cloud Serverless Elasticsearch projects, through the REST API and the Agent Builder MCP server. Elastic Cloud Hosted and self-managed Elasticsearch run the same engine and are not scored apart
- Search modes: Full-text, `dense_vector` kNN (approximate or exact), `sparse_vector`, the managed `semantic_text` workflow, and hybrid search with reciprocal rank fusion
- MCP server: Agent Builder MCP server at `{KIBANA_URL}/api/agent_builder/mcp`, or `/s/{SPACE_NAME}/api/agent_builder/mcp` for a Kibana space. API key on any deployment, OAuth 2.1 on Serverless only. Exposes built-in and custom Agent Builder tools
- Credentials: API keys with `role_descriptors` (cluster, index and Kibana application privileges) and an expiry. OAuth connections act with the consenting user's permissions, can be revoked singly, and lapse after 30 days unused
- OpenAPI: Elasticsearch Serverless API, OpenAPI 3.0.3, 223 paths and 311 operations, generated from elastic/elasticsearch-specification, updated 6 October 2026
- Rate limits: No request rate limit with numbers found. Project limits are 15,000 indices a project, 500 projects an organisation and 1 TB a Vector Database project. A busy cluster answers 429
- Pagination: `from` and `size` up to 10,000 hits, then `search_after`. `_source` includes and excludes size the response
- Serverless billing: Virtual compute units (VCUs) for ingest, search and machine learning, storage per GB a month and egress per GB. Ingest scales to zero after 15 minutes idle. Search keeps a billed baseline
- Agent Builder billing: 1,000 executions a month free, then from $0.025 an execution. A turn over 50,000 input tokens counts as more than one. Error responses are not billed
- Trial: 14 days on Elastic Cloud, no credit card. The trial terms allow only internal evaluation and forbid publishing performance data
- SLA: Serverless SLA of 12 September 2025, 99.95 per cent monthly uptime, Platinum or Enterprise subscription level only. Credits of 10, 30 or 100 per cent, requested by support ticket within 10 days
- Releases: 9.5.0 tagged 29 July 2026, 9.5.3 on 1 September, 9.5.4 on 9 September, 9.5.5 on 30 September. Clients `@elastic/elasticsearch` 9.5.1 on npm and `elasticsearch` 9.5.1 on PyPI (9 September 2026)
- Licence: Source under AGPL-3.0, SSPL-1.0 or Elastic Licence 2.0 at the user's choice. Code in the `x-pack` folder is under Elastic Licence 2.0 only. Serverless is a closed hosted service
- Certifications: SOC 2 and SOC 3, ISO/IEC 27001, 27017 and 27018, PCI DSS, HIPAA, FedRAMP High and Moderate, CSA STAR, per elastic.co/trust
- Data deletion: The monthly terms say content is deleted within 45 days of the customer deleting all projects, apart from backups and copies the law requires
- Prices: Serverless search compute, VCU-hour $0.09 per compute unit; Serverless ingest compute, VCU-hour $0.14 per compute unit; Serverless storage $0.047 per GB per month; Serverless egress $0.05 per GB of traffic; Agent Builder execution $0.025 per call

- Scores: Reliability 62, Performance pending, Schema & documentation 88, Agent ergonomics 77, Security & auth 72, Payments & pricing 35, Task success pending, Maintenance & community 83, Transparency & trust 71 · negative events -2 · total over the 7 assessed categories
- Why: Reliability, Graded as a hosted service on Elastic Cloud Serverless. · Schema & documentation, OpenAPI 3.0.3 for the Serverless API, 223 paths and 311 operations, downloadable as JSON or YAML (25). · Agent ergonomics, The API sizes responses with `size` and `_source` includes and excludes. · Security & auth, API keys take role descriptors that limit cluster, index and Kibana privileges and carry an expiry, and the MCP server accepts OAuth 2.1 on… · Payments & pricing, No x402, MPP or L402 in the docs index, the OpenAPI file or the pricing page (0). · Maintenance & community, Elasticsearch 9.5.5 was tagged on 30 September 2026 and announced on 6 October (30). · Transparency & trust, Source is under AGPL-3.0, SSPL-1.0 or Elastic Licence 2.0, with `x-pack` under Elastic Licence 2.0 only, and Serverless itself is closed (22…
- Sources: 31, open questions: 10, both in the full twin
- Capabilities: db.vector, db.hybrid, db.fulltext, db.filters, db.serverless
- JSON: https://www.anchorterminal.com/api/v1/tools/elasticsearch.json
- Verify (for the vendor): the badge `https://www.anchorterminal.com/badges/elasticsearch.svg` or a link to https://www.anchorterminal.com/tools/elasticsearch from a page on elastic.co or one of its subdomains, or the README of github.com/elastic/elasticsearch, then `POST https://www.anchorterminal.com/api/v1/verify` `{"slug", "url"}` or `verify_listing` at /mcp; re-checked weekly, no effect on the grade. Snippets in the full twin.

## Before you call it

1. Send `Authorization: ApiKey <key>` to the project's Elasticsearch URL. The MCP server is on the Kibana URL at `/api/agent_builder/mcp`
2. Create the MCP key with `feature_agentBuilder.read` and only the index patterns needed, or the endpoint answers 403
3. On 429, wait and retry with exponential backoff. Do not set short client timeouts, because a retried request joins the back of the queue
4. Page past 10,000 hits with `search_after`, not `from` and `size`
5. Tool calls made directly through the Tools API skip Agent Builder's confirmation prompts, so restrict the key instead

## Connect

```bash
npm install @elastic/elasticsearch
```

```bash
curl -X GET "${ES_URL}/_cat/indices?v=true" \
  -H "Authorization: ApiKey ${API_KEY}"
```
Full config and headless snippets are in the full page. Through letme (picks today, calling later): https://letme.dev/elasticsearch

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| --- | --- | --- | --- | --- |
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## Panel reviews (0, desk reviews from public material, no calls made)