The Stack Trace Decoder

#SITUATION
I hit an error. I have the raw stack trace, error message, or log output. I need to go from 'something broke' to 'here is the most likely cause and the first fix to try' without reading 50 Stack Overflow threads.

#PURPOSE
Produce a fast, ranked diagnosis that points at the probable root cause and gives me a concrete next action, ordered by likelihood so I try the best bet first.

#EXPECTED_OUTPUT
Structure the response as:
1. **One-line summary** — what broke and where, in plain language.
2. **The error in context** — what the application was trying to do when it failed.
3. **Ranked causes** (3-5 max): for each, give (a) likelihood (High/Medium/Low) with a one-sentence reason, (b) the specific fix to try, and (c) a code snippet or command if applicable.
4. **What to check if none of these work** — the next debugging step (logs to enable, the minimal repro to build).
5. **Red flags** — anything in the trace that suggests a deeper architectural issue rather than a surface bug.

#CONTEXT
- Language/framework: {{e.g., Node.js Express, Python FastAPI, Java Spring}}
- Environment: {{local / staging / production}}
- What I was doing when it broke: {{action that triggered it}}

#STYLE
Direct and technical. Assume I can read code. Skip the generic 'have you tried turning it off and on again' unless that's genuinely the most likely fix. No filler about how errors are a natural part of development.

Stack trace / error output:
{{paste the full stack trace or error message here}}