# Customer.io

[customer.io](https://customer.io)

- **Overall score:** 85/100 (Grade B)
- **Checks passed:** 14 / 29
- **Last computed:** 2026-05-11

## Components

### Content Discoverability

- **Score:** 80/100 · **Status:** fail
- **Summary:** 1 failed and 2 warnings across 6 AFDocs checks.
- **Rationale:** Agents need a clear entry point and crawl map before they can reliably discover the right pages.
- **Reference:** [AFDocs reference](https://afdocs.dev)

**Checks**

- ⚠️ **LLMS TXT Exists** — llms.txt found but only reachable via cross-host redirect (agents may not follow it) Your llms.txt is only reachable via a cross-host redirect, which some agents don't follow. Serve llms.txt directly from the same host as your documentation, or add a same-host redirect.
- ✅ **LLMS TXT Valid** — llms.txt follows the proposed structure (H1, blockquote, heading-delimited link sections)
- ✅ **LLMS TXT Size** — llms.txt is 1,471 characters (under 50,000 threshold)
- ✅ **LLMS TXT Links Resolve** — All 10 same-origin links resolve (10 total links)
- ❌ **LLMS TXT Links Markdown** — Same-origin links point to HTML and no markdown alternatives detected Your llms.txt links point to HTML pages. Update them to .md URL variants so agents receive markdown instead of converted HTML.
- ⚠️ **LLMS TXT Directive** — llms.txt directive found in 14 of 15 sampled pages, but buried deep in the page (past 50%) An llms.txt directive was found on some pages but is missing from others, or is buried deep in the page. Ensure the directive appears near the top of every documentation page.

### Markdown Availability

- **Score:** 93/100 · **Status:** pass
- **Summary:** 2 AFDocs checks pass.
- **Rationale:** When markdown is available directly, agents spend less effort stripping presentation markup and guessing structure.
- **Reference:** [AFDocs reference](https://afdocs.dev)

**Checks**

- ✅ **Markdown Url Support** — 14/15 sampled pages support .md URLs (93%)
- ✅ **Content Negotiation** — 14/15 sampled pages support content negotiation (93%)

### Page Size and Truncation Risk

- **Score:** 80/100 · **Status:** fail
- **Summary:** 1 failed across 4 AFDocs checks.
- **Rationale:** Large pages and delayed primary content increase truncation risk and make retrieval less reliable.
- **Reference:** [AFDocs reference](https://afdocs.dev)

**Checks**

- ✅ **Rendering Strategy** — All 15 sampled pages contain server-rendered content
- ✅ **Page Size Markdown** — All 14 pages under 50K chars (median 6K, max 18K)
- ❌ **Page Size Html** — 9 of 15 sampled pages convert to over 100K chars (max 273K, 79% boilerplate) 9 of 15 pages convert to over 100K characters of markdown. Reduce inline CSS/JS, break large pages, or provide markdown versions as a smaller alternative.
- ✅ **Content Start Position** — Content starts within first 10% on all 15 sampled pages (median 10%)

### Content Structure

- **Score:** 100/100 · **Status:** pass
- **Summary:** 3 AFDocs checks pass.
- **Rationale:** Predictable sections, valid code fences, and serialized tabs make the content easier for agents to parse correctly.
- **Reference:** [AFDocs reference](https://afdocs.dev)

**Checks**

- ✅ **Tabbed Content Serialization** — No tabbed content detected across 15 sampled pages
- ✅ **Section Header Quality** — No tabbed content found; header quality check not applicable
- ✅ **Markdown Code Fence Validity** — All 18 code fences properly closed across 15 pages

### URL Stability and Redirects

- **Score:** 96/100 · **Status:** fail
- **Summary:** 1 failed across 2 AFDocs checks.
- **Rationale:** Stable URLs and sane redirect behavior prevent retrieval drift and broken tool references.
- **Reference:** [AFDocs reference](https://afdocs.dev)

**Checks**

- ❌ **Http Status Codes** — 1 of 15 sampled pages return 200 for non-existent URLs (soft 404) Your site returns 200 for non-existent pages (soft 404). Agents try to extract information from the error page content instead of recognizing the page is missing. Configure your server to return 404 for pages that don't exist.
- ✅ **Redirect Behavior** — All 15 redirect(s) across 15 sampled pages are same-host HTTP redirects

### Observability and Content Health

- **Score:** 63/100 · **Status:** fail
- **Summary:** 1 failed and 1 skipped across 3 AFDocs checks.
- **Rationale:** Coverage, parity, and cache behavior determine whether agents can trust the content they retrieve.
- **Reference:** [AFDocs reference](https://afdocs.dev)

**Checks**

- ⏭️ **LLMS TXT Freshness** — No sitemap found; cannot assess llms.txt freshness without a sitemap as ground truth
- ❌ **Markdown Content Parity** — 6 of 14 pages have substantive content differences between markdown and HTML (avg 22% missing) 6 pages have substantive content differences between markdown and HTML (avg 22% missing). Agents receiving the markdown version are getting outdated or incomplete content. Regenerate markdown from source or fix the build pipeline.
- ✅ **Cache Header Hygiene** — All 16 endpoints have appropriate cache headers

### Authentication and Access

- **Score:** 100/100 · **Status:** partial
- **Summary:** 1 skipped across 2 AFDocs checks.
- **Rationale:** Agents need either public access or a clear alternative path when documentation is gated behind auth.
- **Reference:** [AFDocs reference](https://afdocs.dev)

**Checks**

- ✅ **Auth Gate Detection** — All 15 sampled pages are publicly accessible
- ⏭️ **Auth Alternative Access** — All docs pages are publicly accessible; no alternative access paths needed

### Full Content Discoverability

- **Score:** 0/100 · **Status:** fail
- **Summary:** llms-full.txt has 1 failing check.
- **Rationale:** A full-document snapshot gives long-context agents a single canonical corpus to ingest without repeated crawling.
- **Reference:** [llms-full.txt guide](https://www.mintlify.com/docs/ai/llmstxt#llms-full-txt)

**Checks**

- ❌ **LLMS Full Exists** — No llms-full.txt file was discovered.
- ⏭️ **LLMS Full Size** — Skipped because llms-full.txt was not found.
- ⏭️ **LLMS Full Valid** — Skipped because llms-full.txt was not found.
- ⏭️ **LLMS Full Links Resolve** — Skipped because llms-full.txt was not found.

### Agent Skills

- **Score:** 0/100 · **Status:** fail
- **Summary:** skill.md has 1 failing check.
- **Rationale:** Agent skills provide product-specific operating guidance that plain documentation pages do not encode on their own.
- **Reference:** [skill.md guide](https://www.mintlify.com/docs/ai/skillmd)

**Checks**

- ❌ **Skill MD** — No agent skill definition was discovered.

### MCP Server

- **Score:** 0/100 · **Status:** fail
- **Summary:** MCP has 1 failing check.
- **Rationale:** A discoverable MCP server lets agents use first-class tools instead of scraping pages and inferring behavior.
- **Reference:** [MCP guide](https://www.mintlify.com/docs/ai/model-context-protocol)

**Checks**

- ❌ **MCP Server Discoverable** — No MCP server was discovered at the expected endpoints.
- ⏭️ **MCP Tool Count** — Skipped because the MCP server was not discoverable.