# StackOne vs Unified.to MCP Server

> StackOne scores 69.1 (B) to Unified.to's 61.9 (C) for app automation. Prices, MCP, x402, uptime and agent notes side by side.

- Canonical: https://www.anchorterminal.com/compare/stackone-vs-unified-to-mcp
- Markdown: https://www.anchorterminal.com/compare/stackone-vs-unified-to-mcp.md (~2,350 tokens)
- Slim: https://www.anchorterminal.com/compare/stackone-vs-unified-to-mcp.min.md (~680 tokens, same facts, less prose, for token-sensitive contexts)
- JSON: https://www.anchorterminal.com/compare/stackone-vs-unified-to-mcp.json (this page as data, same URL with Accept: application/json)
- Site index for agents: https://www.anchorterminal.com/llms.txt (full text: https://www.anchorterminal.com/llms-full.txt)
- API: https://www.anchorterminal.com/api/v1/index.json
- Updated: 2026-10-09

StackOne scores 69.1 (B) on agent readiness against Unified.to MCP Server's 61.9 (C), and leads in 5 of 7 scored categories. Both do app automation.

- StackOne: grade B, 69.1/100, rank #198 of 950. Markdown https://www.anchorterminal.com/tools/stackone.md · JSON https://www.anchorterminal.com/api/v1/tools/stackone.json
- Unified.to MCP Server: grade C, 61.9/100, rank #455 of 950. Markdown https://www.anchorterminal.com/tools/unified-to-mcp.md · JSON https://www.anchorterminal.com/api/v1/tools/unified-to-mcp.json
- Best agent tool access platforms: https://www.anchorterminal.com/best/aggregator/index.md
- All 28 tool access comparisons: https://www.anchorterminal.com/compare/aggregator/index.md

## Which one, for what

### StackOne (B)

Good for: A company that wants one governed MCP endpoint for staff agents across business systems, and product teams embedding per-customer connections with HR, recruiting and CRM coverage.

Ahead on:
- Reliability, 80 against 73
- Security & auth, 69 against 50
- Payments & pricing, 38 against 30

Also in its favour:
- Free to start without a card

Watch for: Session token URLs (`https://api.stackone.com/mcp?token=...`) put the credential in the query string, cover one linked account and expire after one year by default

### Unified.to MCP Server (C)

Good for: A B2B software team that already uses or plans to use Unified's API and wants the same customer connections exposed to an LLM, with data read live from the source app.

Watch for: The default credential is a workspace API key. The docs say it grants access to all connections and the whole Unified.to account


## Score by category

| Category | Weight | StackOne | Unified.to MCP Server | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 80 | 73 | StackOne +7 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 78 | 81 | Unified.to MCP Server +3 |
| Agent ergonomics | 13% (16.2 this run) | 75 | 71 | StackOne +4 |
| Security & auth | 14% (17.5 this run) | 69 | 50 | StackOne +19 |
| Payments & pricing | 10% (12.5 this run) | 38 | 30 | StackOne +8 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 84 | 84 | even |
| Transparency & trust | 7% (8.8 this run) | 69 | 66 | StackOne +3 |
| Negative events | ≤15 | -2 | -3 | |
| **Total** | | **69.1 · B** | **61.9 · C** | |

## Facts side by side

| Fact | StackOne | Unified.to MCP Server |
| --- | --- | --- |
| Kind | MCP server | MCP server |
| Vendor | StackOne Technologies Limited | Unified API Inc. |
| Hosted endpoint | `https://mcp.stackone.com/mcp` | `https://mcp-api.unified.to/mcp` |
| Transports | Streamable HTTP, HTTP | Streamable HTTP |
| Auth | OAuth or key | OAuth or key |
| Pricing | Freemium | Paid |
| x402 | no | no |
| Licence | Proprietary service under StackOne's SaaS Terms and Conditions. The Agent SDKs (`@stackone/ai`, `stackone-ai`) and the Defender package (`@stackone/defender`) are Apache-2.0 | Proprietary service under Unified.to's Terms of Service. The linked repository is sample client code |
| Read-only variant documented | no | no |
| llms.txt | yes | yes |
| MCP registry | `com.stackone/mcp` | `to.unified/core` |
| Last release | 2026-09-24 | 2026-10-08 |
| Terms last updated | 2026-03-30 | no date given |
| Privacy policy last updated | 2023-12-01 | 2026-10-02 |
| Customer content may train models | not found in the text | not found in the text |
| Terms restrict automated access | not found in the text | not found in the text |
| Terms restrict benchmarking | not found in the text | yes |
| Terms or service can change without notice | not found in the text | not found in the text |
| Arbitration or class-action waiver | not found in the text | not found in the text |
| Popularity | 30 stars, 277 npm/wk | 22k npm/wk |

## Verdicts

**StackOne.** StackOne's MCP server signs each person in with OAuth, lets them grant individual accounts and actions, and by default exposes two search and execute tools in place of the full catalogue. Session token URLs carry the credential in the query string for a year by default, and the Consumption Schedule and pricing page disagree on whether failed calls are billed.

**Unified.to MCP Server.** Every previewed tool carries a typed input schema and read-only, destructive and idempotent annotations, and the list can be narrowed by permission or tool name. The default credential is a workspace API key that reaches every connection, and the SSE transport was removed on 23 September 2026 in the changelog entry that announced it.

## Before you call either

### StackOne

1. Send `Accept: application/json,text/event-stream` on every MCP request to `https://api.stackone.com/mcp`, by POST only. Without it the server answers 406
2. In `search_execute` mode call `{provider}_search_actions` first and pass the returned `action_id` to `{provider}_execute_action`. Never hardcode action ids
3. Pass the API key as the Basic auth username with an empty password, and name the linked account in `x-account-id`
4. On 429 or 408 wait the seconds given in `Retry-After`. StackOne has already retried a provider's 429 up to five times within a 60-second request lifetime
5. On 412 read `errorCode` and `details.statusReasons`. `AccountErrorStatus` needs a person to re-authenticate the linked account

### Unified.to MCP Server

1. Use the host for the workspace's region. US is `mcp-api.unified.to`, EU is `mcp-api-eu.unified.to` and AU is `api-au.unified.to`. A credential on another region's host resolves to not found
2. Send the key as `Authorization: Bearer <key>` and put `connection=<id>` in the URL. Without `connection` the server lists workspace management tools, not the customer's data tools
3. Pass `tools` or `permissions` in the URL before listing. An unfiltered connection can list dozens of tools with large output schemas
4. Expect HTTP 429 on tool calls since 23 September 2026. Unified does not queue or retry, so back off and retry yourself
5. Page with `limit` (100 at most on most endpoints) and `offset`, and stop when a page returns fewer records than `limit`

## Questions

### Which is better for AI agents, StackOne or Unified.to MCP Server?

StackOne scores 69.1 (B) on agent readiness against Unified.to MCP Server's 61.9 (C), and leads in 5 of 7 scored categories.

### Do StackOne and Unified.to MCP Server need an API key?

Both take an API key or an OAuth sign-in.

### Can an agent call StackOne and Unified.to MCP Server without installing anything?

Yes. StackOne has a hosted endpoint at https://mcp.stackone.com/mcp and Unified.to MCP Server at https://mcp-api.unified.to/mcp.


## For agents

- This comparison as JSON: https://www.anchorterminal.com/compare/stackone-vs-unified-to-mcp.json, and with the fewest tokens: https://www.anchorterminal.com/compare/stackone-vs-unified-to-mcp.min.md
- Over MCP at https://www.anchorterminal.com/mcp (no key): `compare_tools {"a": "stackone", "b": "unified-to-mcp"}`. From a terminal: `anchor compare stackone unified-to-mcp`
- Each listing in full: https://www.anchorterminal.com/api/v1/tools/stackone.json and https://www.anchorterminal.com/api/v1/tools/unified-to-mcp.json

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