Document cleanup verification details

docs/troubleshooting.md

@@ -146,26 +146,33 @@ Symptom:
 
 - CLI run/render error reading input artifacts.
 - HTTP `400 artifact_read_failed`.
+- HTTP `400 artifact_not_allowed`.
 
 Likely cause:
 
 - File path in input mapping does not exist or is unreadable.
 - Unsupported artifact reference type in HTTP request.
+- HTTP `file` input references are disabled because no artifact root is configured.
+- HTTP `file` input path escapes the configured artifact root.
 
 Diagnostic step:
 
 - Verify every mapped file path exists and is readable by the process.
 - For HTTP, verify each input uses supported `type` values.
+- For HTTP `file` inputs, verify `server.artifact_root` or `serve --artifact-root` is configured and the requested path stays inside that root.
 
 Safe fix:
 
 - Correct file paths and permissions.
 - Use supported input types (`file`, `inline`).
+- Configure a narrow HTTP artifact root when HTTP file inputs are required.
+- Use relative paths under the artifact root, or switch to `inline` inputs.
 
 Relevant links:
 
 - [CLI reference](cli.md)
 - [Configuration reference](config.md)
+- [HTTP API integration](integrations/http-api.md)
 
 ## Prompt Template Render Failures