# Customer.io

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

- **Overall score:** 89/100 (Grade B)
- **Checks passed:** 15 / 29
- **Last computed:** 2026-05-11

## Components

### Content Discoverability

- **Score:** 92/100 · **Status:** fail
- **Summary:** 1 failed and 1 warning 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 at 1 location(s)
- ✅ **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 13 of 14 sampled pages, but buried deep in the page (past 50%); 1 failed to fetch 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:** 87/100 · **Status:** partial
- **Summary:** 2 warnings across 2 AFDocs checks.
- **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** — 13/15 sampled pages support .md URLs (87%); inconsistent support 0 of 15 pages support .md URLs inconsistently. Ensure all documentation pages serve markdown when .md is appended to the URL.
- ⚠️ **Content Negotiation** — Content negotiation partially supported: 13 correct type, 0 wrong type, 2 HTML only Your server returns markdown content for Accept: text/markdown requests but with an incorrect Content-Type header. Set the response Content-Type to text/markdown for proper agent handling.

### Page Size and Truncation Risk

- **Score:** 72/100 · **Status:** fail
- **Summary:** 2 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 13 pages under 50K chars (median 6K, max 26K)
- ❌ **Page Size Html** — 10 of 15 sampled pages convert to over 100K chars (max 124K, 83% boilerplate) 10 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** — 1 of 15 sampled pages have content starting past 50% (worst 56%) 1 of 15 pages have content starting past 50% of the converted output. Agents may never see the documentation content. Move or remove inline CSS/JS that precedes the content area.

### 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 38 code fences properly closed across 14 pages

### URL Stability and Redirects

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

**Checks**

- ✅ **Http Status Codes** — All 15 sampled pages return proper error codes for bad URLs
- ✅ **Redirect Behavior** — All 14 redirect(s) across 15 sampled pages are same-host HTTP redirects

### Observability and Content Health

- **Score:** 89/100 · **Status:** fail
- **Summary:** 1 failed and 1 warning 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** — llms.txt covers 883/1069 sitemap doc pages (83%); 186 missing; 34 llms.txt links not in sitemap (may indicate stale links or incomplete sitemap) Your llms.txt covers 80-95% of your site's pages. 186 live pages are not represented in the index.
- ❌ **Markdown Content Parity** — 6 of 13 pages have substantive content differences between markdown and HTML (avg 24% missing) 6 pages have substantive content differences between markdown and HTML (avg 24% 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:** 50/100 · **Status:** fail
- **Summary:** llms-full.txt has 2 failing checks.
- **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** — Found llms-full.txt.
- ❌ **LLMS Full Size** — llms-full.txt size falls outside the expected range.
- ✅ **LLMS Full Valid** — llms-full.txt has a recognizable markdown structure.
- ❌ **LLMS Full Links Resolve** — Some llms-full.txt links do not resolve successfully.

### 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.