docs: add navigation Skill and progressive AI entry

.agents/docs/README.md

@@ -3,6 +3,8 @@
 These pages explain this repository's navigation and publication responsibilities.
 Host product guides and Protocol specifications remain at their source.
 
+- [Agent discovery entry](../../llms.txt) and [task index](../../skills/index.md).
+- [Install the documentation Skill](install-docs-skill.md).
 - [Contribute and choose the source owner](contributor-guide.md).
 - [Current portal implementation](../../site/README.md).
 - [Planned aggregation boundary](../../integrations/README.md).

.agents/docs/install-docs-skill.md

@@ -0,0 +1,44 @@
+# Install The CordisX Documentation Skill
+
+The `cordisx-docs` Skill teaches an assistant where to look when a CordisX task
+arises. Its only installed file is [SKILL.md](../../skills/cordisx-docs/SKILL.md);
+product documentation stays online with its owner. It is not an npm package,
+runtime plugin, or replacement for `cordisx-plugin-development`.
+
+## Codex
+
+Use the user's configured Skill directory. The current documented Codex
+user-level location is `$HOME/.agents/skills/cordisx-docs/SKILL.md`; see
+[Codex Skill locations](https://developers.openai.com/codex/skills/).
+If an older installation already discovers a copy under `$CODEX_HOME/skills`
+or `$HOME/.codex/skills`, update that existing copy instead of creating a second
+Skill with the same name.
+Check whether that Skill already exists before downloading. Reuse an identical
+copy; preserve local edits instead of overwriting them during initial setup.
+
+For a new installation:
+
+```bash
+SKILL_DIR="$HOME/.agents/skills/cordisx-docs"
+mkdir -p "$SKILL_DIR"
+curl --fail --location https://raw.githubusercontent.com/cordisx/docs/main/skills/cordisx-docs/SKILL.md --output "$SKILL_DIR/SKILL.md"
+```
+
+Read the downloaded file and verify its `name: cordisx-docs` frontmatter. Use the
+agent's Skill discovery/reload mechanism, or start a new session if necessary,
+and verify it lists `cordisx-docs`. A successful download alone does not prove
+the current session has loaded it. Do not restart the CordisX Host for this step.
+
+## Other Assistants Or Read-Only Use
+
+Use the assistant's documented Skill installer/directory for the same standalone
+file. Do not guess another product's configuration path. Without Skill support,
+read [the Docs entry](../../llms.txt) on demand; persistent installation is not
+required to use the guides.
+
+## After Installation
+
+Ask a relevant question, such as "How do I configure a CordisX plugin source?"
+The Skill should select the Marketplace route from [the index](../../skills/index.md),
+not install anything or read all guides. Existing runtime plugins and their
+permissions are unchanged. Remove only this Skill's directory to uninstall it.

README.md

@@ -2,6 +2,18 @@
 
 Navigation and presentation for `https://cordisx.github.io/docs/`.
 
+## Getting started with an AI assistant
+
+```text
+Read the CordisX documentation entry and install its documentation Skill so you can find the right guide for my CordisX requests: https://raw.githubusercontent.com/cordisx/docs/main/llms.txt
+```
+
+After installation, describe your CordisX task normally. The Skill loads relevant
+owner documentation on demand. [Read the entry](llms.txt) or browse the
+[Skill and documentation index](skills/index.md).
+
+## Portal ownership
+
 The current implementation is a static portal linking to the Host and Protocol
 source documentation and the Marketplace. It does not fetch, render, or vendor
 the Markdown from those repositories. [`sources.yaml`](sources.yaml) declares

llms.txt

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+# CordisX Documentation
+
+This entry routes agents to CordisX's owning documentation. It is a navigation
+layer, not another implementation or copy of the Host and plugin manuals.
+
+## Reading Order
+
+1. For first-time product setup, read [CordisX adoption](https://raw.githubusercontent.com/cordisx/cordisx/main/llms.txt).
+   Skip setup already completed in this task.
+2. To make documentation discoverable in future sessions, follow [Install the documentation Skill](.agents/docs/install-docs-skill.md).
+3. For a specific question, choose the smallest relevant entry in [the Skill and documentation index](skills/index.md).
+
+Resolve relative links against this document's URL. Read only the selected topic
+and its required references; do not crawl every linked page or loop back through
+completed prerequisites. Read `SKILL.md` directly when persistent installation
+is not wanted or the agent cannot install skills.
+
+## Boundary
+
+Documentation discovery does not install plugins, launch Apps, grant permissions,
+or log into services. Follow the user's request and the target tool's permissions.
+This public portal does not contain private source addresses or credentials.
+Product commands and compatibility facts belong to their linked owners. Check
+the installed release's help/docs if current `main` differs from that release.

skills/cordisx-docs/SKILL.md

@@ -0,0 +1,30 @@
+---
+name: cordisx-docs
+description: Find authoritative CordisX documentation for installation, startup, profiles, Marketplace sources, plugin installation, troubleshooting, and plugin-development references. Use for CordisX questions and setup; not general Codex account or coding questions.
+---
+
+# CordisX Documentation
+
+Read the [task index](https://raw.githubusercontent.com/cordisx/docs/main/skills/index.md)
+and follow only the route relevant to the user's request. Fetch the linked owner
+document rather than answering product commands from memory or downloading the
+whole documentation set.
+
+- For adoption, follow the Host entry and preserve existing setup. Do not run
+  installation merely because the user asks a question.
+- For an existing plugin, use the Marketplace and the user's selected source.
+  Read that plugin's own guide for service configuration and login.
+- For plugin implementation, continue with the separate plugin-development
+  Skill; this Skill does not duplicate its contract or workflow.
+- If the user provides a private entry, read it only in the authorized context.
+  Keep private URLs, source metadata, and credentials out of public files.
+
+Resolve relative links against the containing document's URL. A prerequisite
+already completed need not be performed again. An inaccessible link is a missing
+reference, not permission to guess endpoints or commands. Documentation on `main`
+may be newer than the installed CLI; check help and the installed release tag
+before applying version-sensitive instructions.
+
+Distinguish installation, running Host, plugin activation, permission state, and
+provider-account login. Documentation discovery does not authorize additional
+effects. Cite the source used and report what was actually verified.

skills/index.md

@@ -0,0 +1,17 @@
+# CordisX Skills And Documentation
+
+Choose one route for the current task. These are links to authoritative owners,
+not an instruction to load every document.
+
+| Task                                                   | Read first                                                                                                                    | Continue only when relevant                            |
+| ------------------------------------------------------ | ----------------------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------ |
+| Install or start CordisX                               | [Host entry](https://raw.githubusercontent.com/cordisx/cordisx/main/llms.txt)                                                 | Its Getting started and startup Q&A links              |
+| Configure a Marketplace or install an existing plugin  | [Marketplace entry](https://raw.githubusercontent.com/cordisx/marketplace/main/llms.txt)                                      | The selected source's own guide and plugin README      |
+| Keep documentation discoverable                        | [Install the navigation Skill](../.agents/docs/install-docs-skill.md)                                                         | [cordisx-docs](cordisx-docs/SKILL.md)                  |
+| Add or change a plugin's behavior                      | [Plugin-development Skill](https://raw.githubusercontent.com/cordisx/cordisx/main/skills/cordisx-plugin-development/SKILL.md) | Its task-specific references                           |
+| Understand Host configuration or troubleshoot behavior | [Host documentation index](https://raw.githubusercontent.com/cordisx/cordisx/main/.agents/docs/README.md)                     | The owning topic, at the installed release when needed |
+| Check versioned plugin contracts                       | [Protocol index](https://raw.githubusercontent.com/cordisx/cordisx-protocol/main/.agents/docs/README.md)                      | The contract version named by the package              |
+
+The navigation Skill routes reading; the development Skill guides implementation.
+Neither is a CordisX runtime plugin. For a private source, use the entry supplied
+by the user instead of guessing an internal URL or copying it into public docs.