# Common Issues
## "No API key found"
```
error: No API key found.
Set ANTHROPIC_API_KEY or API_KEY environment variable.
```
**Fix:** Set your Anthropic API key:
```bash
export ANTHROPIC_API_KEY=sk-ant-api03-...
```
yoyo checks `ANTHROPIC_API_KEY` first, then `API_KEY`. At least one must be set and non-empty.
## "No input on stdin"
```
No input on stdin.
```
This happens when you pipe empty input to yoyo:
```bash
**Fix:** Make sure your piped input contains actual content.
## Model errors
```
error: [API error message]
```
This appears when the Anthropic API returns an error. Common causes:
- **Invalid API key** — check your key is correct and active
- **Rate limiting** — you're sending too many requests; wait and retry
- **Model unavailable** — the model you specified doesn't exist or you don't have access
**Automatic retry:** yoyo automatically retries transient errors (rate limits, server errors, network issues) with exponential backoff — up to 3 retries with 1s, 2s, 4s delays. You'll see a dim message like `⚡ retrying (attempt 2/4, waiting 2s)...` when this happens. Auth errors (401, 403) and invalid requests (400) are shown immediately without retrying.
Use `/retry` to manually re-send the last prompt after a non-transient error is resolved.
## Context window full
```
⚠ Context is getting full. Consider /clear or /compact.
```
Your conversation is approaching the 200,000-token context limit.
**Fix:** Use `/compact` to compress the conversation, or `/clear` to start fresh.
yoyo auto-compacts at 80% capacity, but you can compact earlier if you prefer.
## "warning: Failed to load skills"
```
warning: Failed to load skills: [error]
```
The `--skills` directory couldn't be read. yoyo continues without skills.
**Fix:** Check that the path exists and contains valid skill files.
## "unknown command: /foo"
```
unknown command: /foo
type /help for available commands
```
You typed a command yoyo doesn't recognize.
**Fix:** Type `/help` to see available commands.
## "not in a git repository"
```
error: not in a git repository
```
You used `/diff` or `/undo` outside a git repo.
**Fix:** Navigate to a directory that's inside a git repository before starting yoyo.
## Ctrl+C behavior
- **First Ctrl+C** — cancels the current response; you can type a new prompt
- **Second Ctrl+C** (or Ctrl+D) — exits yoyo
If a tool execution is hanging, Ctrl+C will abort it.
## Session file errors
```
error saving: [error]
error reading yoyo-session.json: [error]
error parsing: [error]
```
Session save/load failed. Common causes:
- **Disk full** — free space and try again
- **Permission denied** — check file permissions
- **Corrupt file** — delete the session file and start fresh