Intelligent Failure Recovery

devx features an automatic, two-tier failure diagnosis engine hooked into every command. When a command fails with a non-zero exit code, devx intercepts the error and attempts to explain the root cause and provide an actionable fix before exiting.

How it works

The diagnosis engine operates in two tiers:

Tier 1: Pattern Matching (No AI)

devx maintains a built-in knowledge base of common failure modes (e.g., password mismatches, port conflicts, OOMKilled containers, expired certificates). It analyzes the exit code and stderr output against this knowledge base.

If a match is found, devx immediately prints a diagnosis and a suggested command to fix it. This tier works entirely locally, is instantaneous, and requires zero configuration.

$ devx db spawn postgres
Error: listen tcp :5432: bind: address already in use

╭───────────────────────────────────────────────────────────────────╮
│ 💡 Diagnosis                                                      │
│                                                                   │
│ Port conflict — another process is already listening on the       │
│ required port.                                                    │
│                                                                   │
│   → lsof -i :<port>   # find the conflicting process, then kill   │
│                                                                   │
│   (rule-based)                                                    │
╰───────────────────────────────────────────────────────────────────╯

Tier 2: AI-Enhanced Analysis

If no pattern matches the error, and a local AI provider is available (such as Ollama or LM Studio), devx silently collects the runtime context (container states, port bindings, and redacted environment variables) and requests a custom diagnosis.

$ devx up
Error: connection refused

╭───────────────────────────────────────────────────────────────────╮
│ 💡 Diagnosis                                                      │
│                                                                   │
│ The 'api' container failed to start because it cannot reach the   │
│ 'postgres' database. The database is currently in an 'exited'     │
│ state, likely due to a misconfigured devx.yaml volume mount.      │
│                                                                   │
│   → devx db rm postgres && devx db spawn postgres                 │
│                                                                   │
│   (ai)                                                            │
╰───────────────────────────────────────────────────────────────────╯

To ensure a smooth developer experience, AI calls have a strict 15-second timeout. If the AI is too slow, or if no provider is configured, the diagnosis is silently skipped, allowing the standard error to surface without delay.

Suppressing Output

The diagnosis engine is automatically disabled when the --json flag is used. This ensures that AI agents and scripts parsing structured output do not receive free-form diagnosis text injected into their JSON streams.