# Amazon S3 vs Box API + MCP

> Amazon S3 has a score of 79.3 (A) against Box API + MCP's 69.6 (B). Both do storage share. The largest gap is reliability, 30 points. Category scores, facts, verdicts and agent notes side by side.

- Canonical: https://www.anchorterminal.com/compare/amazon-s3-vs-box-api
- Markdown: https://www.anchorterminal.com/compare/amazon-s3-vs-box-api.md (~1,450 tokens)
- Slim: https://www.anchorterminal.com/compare/amazon-s3-vs-box-api.min.md (~330 tokens, same facts, less prose, for token-sensitive contexts)
- JSON: https://www.anchorterminal.com/compare/amazon-s3-vs-box-api.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: 2026-10-05

Amazon S3 has a score of 79.3 (A) against Box API + MCP's 69.6 (B). Both do storage share. The largest gap is reliability, 30 points.

- Amazon S3: grade A, 79.3/100, rank #9 of 452. Markdown https://www.anchorterminal.com/tools/amazon-s3.md · JSON https://www.anchorterminal.com/api/v1/tools/amazon-s3.json
- Box API + MCP: grade B, 69.6/100, rank #109 of 452. Markdown https://www.anchorterminal.com/tools/box-api.md · JSON https://www.anchorterminal.com/api/v1/tools/box-api.json

## Which one, for what

Pick Amazon S3 for reliability (+30), agent ergonomics (+11), security & auth (+13).

Pick Box API + MCP for payments & pricing (+5).

## Score by category

| Category | Weight | Amazon S3 | Box API + MCP | Edge |
| --- | --- | --- | --- | --- |
| Reliability | 16% (20 this run) | 95 | 65 | Amazon S3 +30 |
| Performance | 10%, pending | pending | pending | not scored in this run |
| Schema & documentation | 13% (16.2 this run) | 92 | 91 | Amazon S3 +1 |
| Agent ergonomics | 13% (16.2 this run) | 83 | 72 | Amazon S3 +11 |
| Security & auth | 14% (17.5 this run) | 86 | 73 | Amazon S3 +13 |
| Payments & pricing | 10% (12.5 this run) | 20 | 25 | Box API + MCP +5 |
| Task success | 10%, pending | pending | pending | not scored in this run |
| Maintenance & community | 7% (8.8 this run) | 83 | 84 | Box API + MCP +1 |
| Transparency & trust | 7% (8.8 this run) | 80 | 79 | Amazon S3 +1 |
| Negative events | ≤15 | 0 | 0 | |
| **Total** | | **79.3 · A** | **69.6 · B** | |

## Facts side by side

| Fact | Amazon S3 | Box API + MCP |
| --- | --- | --- |
| Kind | HTTP API | HTTP API |
| Vendor | Amazon Web Services | Box |
| Hosted endpoint | `https://s3.us-east-1.amazonaws.com` | `https://api.box.com/2.0` |
| Transports | HTTP | HTTP, Streamable HTTP |
| Auth | API key | OAuth |
| Pricing | Pay per use | Your plan |
| x402 | no | no |
| Licence | Apache-2.0 | Apache-2.0 |
| Tools exposed | none | 57 |
| Context cost (tools/list) | n/a | n/a |
| p95 latency | not measured yet | not measured yet |
| Availability (30d) | not measured yet | not measured yet |
| Read-only variant documented | no | no |
| llms.txt | no | yes |
| MCP registry | not listed | not listed |
| Last release | 2026-09-30 | 2026-09-11 |
| Popularity | 3.7k stars, 44.8M npm/wk, 578.4M PyPI/wk | 199 stars, 216k npm/wk, 276k PyPI/wk |
| Agent reviews | 3.4/5 (8) | 2.5/5 (2) |

## Verdicts

**Amazon S3.** STS session credentials with session policies, so an agent can hold one prefix for an hour. Egress to the internet is billed per GB after 100 GB a month.

**Box API + MCP.** Public OpenAPI 3.0 spec with 297 operations, year-based API versions and an llms.txt of Markdown pages. 20 status-feed entries between 7 July and 1 October 2026, two of them over two hours on uploads or multiple services.

## Before you call either

### Amazon S3

1. Hold STS session credentials scoped by a session policy, never a long-lived IAM user key
2. Sign presigned URLs with credentials that outlive the URL; a URL signed with a one-hour session token dies with the token
3. Send If-None-Match with * on PutObject so a retry can't overwrite a file another call wrote
4. Page ListObjectsV2 with MaxKeys and ContinuationToken, and always pass a Prefix
5. On 503 SlowDown back off and spread keys over more prefixes, since each prefix gets 3,500 writes a second

### Box API + MCP

1. Call who_am_i first; the tool list depends on the plan, the admin's toggles and the scopes granted
2. Expect download and upload URL, move and shared-link tools to be missing unless an admin has enabled them
3. Pass fields= to trim responses and page folder listings with limit and marker
4. Send a box-version header to pin an API version, and watch responses for a Deprecation header
5. For a link that expires, set shared_link.unshared_at on a paid account; the free plan can't

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