Transport Security: All communication with the server (API and MCP) must be secured with HTTPS.

Execution Environment: The server is assumed to run in a trusted, non-hostile environment. It has direct file system access, which is a powerful capability. Access to the server should be controlled by network rules.

Authentication/Authorization: The PRD does not specify any multi-user or authentication requirements. The server is treated as a single-tenant system. If needed in the future, standard token-based authentication (e.g., API keys, OAuth2) could be added at the API gateway level or within FastAPI.

API Errors: Invalid requests (e.g., bad paths, malformed content) will result in standard HTTP error codes (4xx) with a descriptive JSON body, as required by USAB-2.

Server Errors: Unexpected internal errors will result in HTTP 5xx codes. All such errors will be logged with a full stack trace for debugging.

Data Integrity: File corruption is prevented through the atomic write mechanism detailed in ADR-004.

Logging: The application will use structured logging (e.g., JSON format) and log to stdout. This allows for easy integration with modern log aggregation tools like the ELK stack, Splunk, or cloud-based logging services. Log levels (DEBUG, INFO, WARN, ERROR) will be used to control verbosity.

Monitoring: FastAPI can be easily instrumented with Prometheus middleware to expose key metrics (e.g., request latency, error rates, memory usage of the index). This allows for proactive monitoring and alerting.