> ## Documentation Index
> Fetch the complete documentation index at: https://docs.fallow.tools/llms.txt
> Use this file to discover all available pages before exploring further.
# fallow flags
> CLI reference for fallow flags. Detect feature flag patterns, environment variable gates, SDK calls, and config-based toggles across your codebase.
Detect feature flag patterns in your codebase. Fallow identifies environment variable flags (`process.env.FEATURE_*`), SDK calls (LaunchDarkly, Statsig, Unleash, GrowthBook), and config object patterns (opt-in). Reports flag locations, detection confidence, and cross-references with dead code findings.
Use `fallow flags --format json` for structured output that agents and scripts can parse. Combine with `--top N` to focus on the most common flags.
```bash theme={null}
fallow flags
```
## Options
### Output
| Flag | Description |
| :---------------------- | :---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| `--top ` | Show only the top N flags |
| `-f, --format ` | Output format: `human` (default), `json`, `sarif`, `compact`, `markdown`, `codeclimate`, `gitlab-codequality`, `pr-comment-github`, `pr-comment-gitlab`, `review-github`, `review-gitlab` |
| `-q, --quiet` | Suppress progress output |
| `--explain` | Add metric explanations. In JSON format, adds a `_meta` object with descriptions and docs links. |
| `--summary` | Print a one-line summary of flag counts at the end of the run. In JSON format, adds a `summary` counts object. |
### Scoping
| Flag | Description |
| :----------------------- | :---------------------------------------------------------- |
| `-r, --root ` | Project root directory (default: current working directory) |
| `-c, --config ` | Path to config file (default: auto-detected) |
| `-w, --workspace ` | Scope output to a single workspace package |
| `--changed-since [` | Only report flags in files changed since a git ref |
| `--production` | Production mode: exclude test/story/dev files |
### Performance
| Flag | Description |
| :-------------- | :-------------------------------------------------------- |
| `--no-cache` | Disable incremental caching (force full re-parse) |
| `--threads ` | Number of parser threads (default: available parallelism) |
| `--performance` | Show pipeline timing breakdown |
### CI
| Flag | Description |
| :-------------------- | :------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| `--ci` | CI mode: equivalent to `--format sarif --fail-on-issues --quiet` |
| `--fail-on-issues` | Exit with code 1 if flags are found |
| `--sarif-file ` | Write SARIF output to a file (in addition to `--format`) |
| `--group-by ` | Group output by `owner` (CODEOWNERS), `directory` (first path component), `package` (workspace package), or `section` (GitLab CODEOWNERS `[Section]` headers). See [global flags](/cli/global-flags#grouped-output). |
### Regression
| Flag | Description |
| :---------------------------------- | :----------------------------------------------------------------------------- |
| `--baseline ` | Compare against a previously saved baseline file |
| `--save-baseline ` | Save current results as a baseline file |
| `--fail-on-regression` | Fail if flag count increased beyond tolerance vs a regression baseline |
| `--tolerance ` | Allowed increase: `"2%"` (percentage) or `"5"` (absolute). Default: `"0"` |
| `--regression-baseline ` | Path to regression baseline file (default: `.fallow/regression-baseline.json`) |
| `--save-regression-baseline ` | Save current flag counts as a regression baseline |
## Detection categories
Fallow detects three categories of feature flag patterns:
| Category | What it finds | Examples |
| :----------------------------- | :------------------------------------------------------ | :-------------------------------------------------------------------------------------------- |
| **Environment variable flags** | `process.env.*` checks used as feature gates | `process.env.FEATURE_NEW_UI`, `process.env.ENABLE_DARK_MODE` |
| **SDK calls** | Feature flag SDK method calls from known providers | LaunchDarkly `variation()`, Statsig `checkGate()`, Unleash `isEnabled()`, GrowthBook `isOn()` |
| **Config object patterns** | Object property lookups used as boolean guards (opt-in) | `config.featureX`, `settings.enableNewFlow` |
Each detected flag includes a confidence level indicating how certain fallow is that the pattern represents a feature flag.
## Examples
```bash Basic analysis theme={null}
# Detect all feature flags
fallow flags
# Show only the top 10 flags
fallow flags --top 10
```
```bash CI integration theme={null}
# JSON output for pipelines
fallow flags --format json --quiet
# SARIF for GitHub Code Scanning
fallow flags --format sarif > flags.sarif
# Compact format (one line per flag)
fallow flags --format compact
# Markdown for PR comments
fallow flags --format markdown | gh pr comment --body-file -
# CodeClimate for GitLab CI
fallow flags --format codeclimate > gl-code-quality-report.json
```
```bash Scoping theme={null}
# Only flags in changed files
fallow flags --changed-since main
# Scope to a workspace package
fallow flags --workspace @app/core
# Production code only
fallow flags --production
```
## JSON output
```json title="$ fallow flags --format json" theme={null}
{
"schema_version": 3,
"version": "2.75.0",
"elapsed_ms": 116,
"feature_flags": [],
"total_flags": 0
}
```
### Key fields
| Field | Type | Description |
| :--------------- | :------ | :-------------------------------------- |
| `schema_version` | integer | JSON schema version (currently 3) |
| `version` | string | Fallow version that produced the output |
| `elapsed_ms` | integer | Analysis duration in milliseconds |
| `feature_flags` | array | Detected feature flag patterns |
| `total_flags` | integer | Total number of detected flags |
## MCP tool
The `feature_flags` MCP tool wraps `fallow flags --format json --quiet --explain`:
```json title="Example request" theme={null}
{
"tool": "feature_flags",
"arguments": {
"top": 10
}
}
```
The response always includes `_meta` explanatory metadata (the MCP wrapper enables `--explain` by default). Returns the same JSON envelope as the CLI.
See [MCP integration](/integrations/mcp) for setup instructions.
## See also
Cross-references feature flags with dead code findings.
Flags available on every fallow command.
Use fallow tools from AI coding agents.
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