diff --git a/docs/faq.md b/docs/faq.md
index 63313df..2a2b718 100644
--- a/docs/faq.md
+++ b/docs/faq.md
@@ -11,4 +11,28 @@ Our core mission includes:
 - Providing plugins and tools for existing chat UIs  
 - Supporting ontology editing and curation workflows with AI assistance
 
-The project serves both as documentation and a practical example of AI agent integration, where GitHub agents can directly contribute to documentation and examples demonstrate real-world AI-assisted curation workflows.
\ No newline at end of file
+The project serves both as documentation and a practical example of AI agent integration, where GitHub agents can directly contribute to documentation and examples demonstrate real-world AI-assisted curation workflows.
+
+## GitHub Copilot Integration
+
+### Why can't GitHub Copilot access OBO PURLs like purl.obolibrary.org?
+
+GitHub Copilot's coding agent includes a firewall that restricts internet access by default to prevent data exfiltration risks. While the agent can access GitHub-related hosts and a recommended allowlist of common package repositories, it blocks access to custom domains like `purl.obolibrary.org` that are commonly used in ontology workflows.
+
+**The Solution:** Repository administrators can allowlist additional hosts in the Copilot firewall settings:
+
+1. Navigate to your repository's **Settings** tab
+2. Select **Copilot**, then **coding agent** from the Code & automation sidebar
+3. Click **Custom allowlist**
+4. Add `purl.obolibrary.org` (or specific URL paths) to the allowlist
+5. Click **Add Rule**, then **Save changes**
+
+**Allowlist formats:**
+- **Domain**: `purl.obolibrary.org` - allows the domain and all subdomains
+- **URL**: `https://purl.obolibrary.org/obo/` - restricts to specific scheme, host, and path
+
+**Workaround:** Until the firewall is configured, use direct GitHub URLs instead of PURLs:
+- ✅ Works: `https://raw.githubusercontent.com/oborel/obo-relations/refs/heads/master/ro-base.owl`
+- ❌ Blocked: `http://purl.obolibrary.org/obo/ro/ro-base.owl`
+
+For more details, see the [GitHub Copilot](reference/clients/github-copilot.md) documentation and GitHub's guide on [customizing the agent firewall](https://docs.github.com/en/copilot/how-tos/use-copilot-agents/coding-agent/customize-the-agent-firewall).
\ No newline at end of file
diff --git a/docs/reference/clients/github-copilot.md b/docs/reference/clients/github-copilot.md
new file mode 100644
index 0000000..38f836b
--- /dev/null
+++ b/docs/reference/clients/github-copilot.md
@@ -0,0 +1,173 @@
+# GitHub Copilot
+
+GitHub Copilot is GitHub's AI pair programmer that can assist with ontology curation and knowledge base maintenance tasks directly within your GitHub repositories.
+
+## Overview
+
+GitHub Copilot includes a coding agent that can help with:
+- Downloading and processing ontology files
+- Executing repository workflows and scripts
+- Making automated commits and pull requests
+- Performing code reviews and quality checks
+
+## Setting Up GitHub Copilot for Ontology Workflows
+
+### Prerequisites
+
+- GitHub Copilot subscription (individual, business, or enterprise)
+- Repository access with Copilot enabled
+- Administrator permissions to configure firewall settings (for custom domain access)
+
+## Firewall Configuration
+
+By default, GitHub Copilot's coding agent includes a firewall that restricts internet access to prevent data exfiltration risks. This can block access to ontology-specific resources like OBO PURLs.
+
+### Understanding the Default Allowlist
+
+The agent's firewall allows access to:
+- GitHub-related hosts (github.com, githubusercontent.com, etc.)
+- OS package repositories (Debian, Ubuntu, Red Hat)
+- Container registries (Docker Hub, Azure, AWS ECR)
+- Programming language package registries (npm, PyPI, Maven, etc.)
+- Certificate authorities for SSL validation
+
+### Configuring Access to OBO Library and Other Ontology Resources
+
+To enable access to `purl.obolibrary.org` and other ontology-related domains:
+
+1. Navigate to your repository's **Settings** tab
+2. In the sidebar, select **Copilot** under the Code & automation section
+3. Click on **coding agent**
+4. Select **Custom allowlist**
+5. Add the domain or URL:
+   - For broad access: `purl.obolibrary.org`
+   - For specific paths: `https://purl.obolibrary.org/obo/`
+6. Click **Add Rule**
+7. Click **Save changes**
+
+### Allowlist Entry Formats
+
+**Domain allowlisting:**
+```
+purl.obolibrary.org
+```
+This allows access to the domain and all subdomains (e.g., `beta.purl.obolibrary.org`).
+
+**URL allowlisting:**
+```
+https://purl.obolibrary.org/obo/
+```
+This restricts access to:
+- Specific scheme (`https` only)
+- Specific host (`purl.obolibrary.org`)
+- Specific path prefix (`/obo/`)
+
+### Common Domains for Ontology Work
+
+Consider allowlisting these domains for ontology curation workflows:
+
+- `purl.obolibrary.org` - OBO Library PURLs
+- `www.ebi.ac.uk` - EBI Ontology Lookup Service
+- `ontobee.org` - Ontobee ontology browser
+- `bioportal.bioontology.org` - BioPortal ontology repository
+
+## Workarounds
+
+### Using Direct GitHub URLs
+
+If firewall configuration is pending or unavailable, you can use direct GitHub raw URLs instead of PURLs:
+
+**Instead of:**
+```
+http://purl.obolibrary.org/obo/ro/ro-base.owl
+```
+
+**Use:**
+```
+https://raw.githubusercontent.com/oborel/obo-relations/refs/heads/master/ro-base.owl
+```
+
+This works because GitHub hosts are already in the default allowlist.
+
+### Mapping PURLs to GitHub URLs
+
+For OBO Library ontologies, the PURL pattern:
+```
+http://purl.obolibrary.org/obo/{ontology}/{file}
+```
+
+Often maps to:
+```
+https://raw.githubusercontent.com/{org}/{ontology}/refs/heads/master/{file}
+```
+
+You can find the exact repository location by visiting the PURL in a browser and checking where it redirects.
+
+## Security Considerations
+
+### Why the Firewall Exists
+
+The firewall prevents potential data exfiltration where malicious code could attempt to send repository data to unauthorized external servers. This is especially important for:
+- Private repositories
+- Repositories with sensitive data
+- Enterprise environments
+
+### Best Practices
+
+1. **Principle of least privilege**: Only allowlist domains you actively need
+2. **Use URL-based rules** when possible to restrict access to specific paths
+3. **Regular audits**: Periodically review your allowlist entries
+4. **Document decisions**: Keep a record of why specific domains were allowlisted
+5. **Consider alternatives**: Use direct GitHub URLs when appropriate
+
+### Disabling the Firewall
+
+While it's possible to disable the firewall entirely, **this is not recommended** as it significantly increases security risks. Only disable the firewall if:
+- You're in a controlled development environment
+- You understand and accept the security implications
+- You have alternative security measures in place
+
+## Troubleshooting
+
+### Issue: "Unable to resolve host address" or 404 errors
+
+**Symptoms:** Copilot reports it cannot download files from ontology PURLs or specific domains.
+
+**Solution:** Check if the domain is allowlisted in the firewall configuration. See [Configuring Access](#configuring-access-to-obo-library-and-other-ontology-resources) above.
+
+### Issue: Some ontology files download, others don't
+
+**Symptoms:** Direct GitHub URLs work, but PURLs fail.
+
+**Explanation:** Direct GitHub URLs are in the default allowlist, but PURL domains require custom allowlist entries.
+
+**Solution:** Add the PURL domain to the custom allowlist or use direct GitHub URLs.
+
+### Issue: Changes to allowlist don't take effect
+
+**Solution:**
+- Ensure you clicked "Save changes" after adding rules
+- Wait a few minutes for settings to propagate
+- Try restarting the Copilot agent if available
+
+## Related Resources
+
+- [GitHub Copilot documentation](https://docs.github.com/en/copilot)
+- [Customizing the agent firewall](https://docs.github.com/en/copilot/how-tos/use-copilot-agents/coding-agent/customize-the-agent-firewall)
+- [Set up GitHub actions](../../how-tos/set-up-github-actions.md)
+- [Instruct the GitHub agent](../../how-tos/instruct-github-agent.md)
+
+## Example: Configuring Copilot for OBO Workflows
+
+Here's a complete example of setting up Copilot for ontology curation:
+
+1. **Enable Copilot** on your ontology repository
+2. **Configure firewall** to allow `purl.obolibrary.org`
+3. **Test access** by asking Copilot to download a test ontology file:
+   ```
+   Download http://purl.obolibrary.org/obo/ro/ro-base.owl
+   ```
+4. **Set up workflows** using the standard OBO tools (ODK, ROBOT, etc.)
+5. **Document your configuration** in your repository's README or contributor guidelines
+
+With proper configuration, Copilot can seamlessly assist with ontology curation tasks while maintaining security through controlled firewall rules.
diff --git a/mkdocs.yml b/mkdocs.yml
index 159af61..7c3d721 100644
--- a/mkdocs.yml
+++ b/mkdocs.yml
@@ -53,6 +53,7 @@ nav:
         - Claude Code: reference/clients/claude-code.md
         - Codex CLI: reference/clients/codex-cli.md
         - Gemini CLI: reference/clients/gemini-cli.md
+        - GitHub Copilot: reference/clients/github-copilot.md
         - Goose: reference/clients/goose.md
   - Glossary: glossary.md