docs: clarify custom endpoint support

.claude-plugin/README.md

@@ -3,3 +3,15 @@
 If you plan to edit `.claude-plugin/plugin.json`, be aware that the Claude plugin validator enforces several **undocumented but strict constraints** that can cause installs to fail with vague errors (for example, `agents: Invalid input`). In particular, component fields must be arrays, `agents` must use explicit file paths rather than directories, and a `version` field is required for reliable validation and installation.
 
 These constraints are not obvious from public examples and have caused repeated installation failures in the past. They are documented in detail in `.claude-plugin/PLUGIN_SCHEMA_NOTES.md`, which should be reviewed before making any changes to the plugin manifest.
+
+### Custom Endpoints and Gateways
+
+ECC does not override Claude Code transport settings. If Claude Code is configured to run through an official LLM gateway or a compatible custom endpoint, the plugin continues to work because hooks, commands, and skills execute locally after the CLI starts successfully.
+
+Use Claude Code's own environment/configuration for transport selection, for example:
+
+```bash
+export ANTHROPIC_BASE_URL=https://your-gateway.example.com
+export ANTHROPIC_AUTH_TOKEN=your-token
+claude
+```

README.md

@@ -748,6 +748,31 @@ This shows all available agents, commands, and skills from the plugin.
 This is the most common issue. **Do NOT add a `"hooks"` field to `.claude-plugin/plugin.json`.** Claude Code v2.1+ automatically loads `hooks/hooks.json` from installed plugins. Explicitly declaring it causes duplicate detection errors. See [#29](https://github.com/affaan-m/everything-claude-code/issues/29), [#52](https://github.com/affaan-m/everything-claude-code/issues/52), [#103](https://github.com/affaan-m/everything-claude-code/issues/103).
 </details>
 
+<details>
+<summary><b>Can I use ECC with Claude Code on a custom API endpoint or model gateway?</b></summary>
+
+Yes. ECC does not hardcode Anthropic-hosted transport settings. It runs locally through Claude Code's normal CLI/plugin surface, so it works with:
+
+- Anthropic-hosted Claude Code
+- Official Claude Code gateway setups using `ANTHROPIC_BASE_URL` and `ANTHROPIC_AUTH_TOKEN`
+- Compatible custom endpoints that speak the Anthropic API Claude Code expects
+
+Minimal example:
+
+```bash
+export ANTHROPIC_BASE_URL=https://your-gateway.example.com
+export ANTHROPIC_AUTH_TOKEN=your-token
+claude
+```
+
+If your gateway remaps model names, configure that in Claude Code rather than in ECC. ECC's hooks, skills, commands, and rules are model-provider agnostic once the `claude` CLI is already working.
+
+Official references:
+- [Claude Code LLM gateway docs](https://docs.anthropic.com/en/docs/claude-code/llm-gateway)
+- [Claude Code model configuration docs](https://docs.anthropic.com/en/docs/claude-code/model-config)
+
+</details>
+
 <details>
 <summary><b>My context window is shrinking / Claude is running out of context</b></summary>