A .NET CLI tool that scans a project directory for FtrIO feature toggle usage and reports the current state of every toggle.

Because FtrIO always resolves toggle state from appsettings.json at runtime, FtrIO.onetwo gives you an instant at-a-glance view of exactly what is enabled or disabled in your codebase right now — and precisely where each toggle is used — without having to open a single source file or config manually.

What it does

FtrIO.onetwo walks a project's source tree, finds every toggle reference, cross-references it against appsettings.json, and outputs a table showing the current state of each toggle.

It detects toggles from four patterns:

Pattern	Use case
[Toggle]	Synchronous method gated by its own name
[ToggleAsync]	Task-returning method gated by its own name
ExecuteMethodIfToggleOn(action, "key")	Manual synchronous gating with an explicit key
ExecuteMethodIfToggleOnAsync(func, "key")	Manual async gating with an explicit key

// Attribute — toggle key is inferred from the method name
[Toggle]
public void SendWelcomeEmail() { }

[ToggleAsync]
public async Task SendNewsletterAsync() { }

// Manual call — toggle key is the string literal argument
featureToggle.ExecuteMethodIfToggleOn(ProcessOrder, "NewCheckoutFlow");
await featureToggle.ExecuteMethodIfToggleOnAsync(SyncDataAsync, "BetaSync");

The FtrIO ecosystem

• FtrIO — the core library. Weaves [Toggle] into your IL at compile time, reads state from appsettings.json at runtime, and optionally syncs from remote sources via the provider pipeline.
• FtrIO.Toaster — a lightweight web UI for managing toggles live. Writes values through ToggleProviderBuffer so changes flush to appsettings.json and are picked up instantly via ReloadOnChange — no file editing, no restart.
• FtrIO.onetwo — a .NET CLI audit tool. Scans your source tree for every toggle reference, cross-references against appsettings.json, and reports each toggle's state (ON / OFF / AB-TEST / TARGETED / RULE-BASED / MISSING) with file and line number.

Requirements

• .NET SDK 6, 8, or 10 (net6.0, net8.0, and net10.0 are all supported)

Installation

Install as a global dotnet tool from NuGet:

dotnet tool install -g FtrIO.onetwo

Usage

ftrio.onetwo [--source <path>] [--config <path>] [--env <name>] [--markdown <output.md>]

Argument	Description
--source <path>	Directory to scan for toggle usage in .cs files. Defaults to the current directory.
--config <path>	Directory to search for appsettings*.json files. Defaults to --source when not specified.
--env <name>	Show a single environment using the base+overlay model (e.g. --env Staging). Omit to show all appsettings files as separate tables.
--markdown <file>	Also write the results to a markdown file at the given path.
--help / -h	Show usage.

--source and --config can also be passed as positional arguments — the first positional value is the source path, the second is the config path.

Examples:

# Scan a project — source and config in the same directory
ftrio.onetwo --source C:\Projects\MyApp

# Source code and config files in separate locations
ftrio.onetwo --source C:\Projects\MyApp --config C:\Projects\MyApp\bin\Debug\net10.0

# Positional shorthand (source then config)
ftrio.onetwo "C:\Projects\MyApp" "C:\Server\configs"

# Explicitly scan against the Staging overlay
ftrio.onetwo --source C:\Projects\MyApp --env Staging

# Also emit a markdown report
ftrio.onetwo --source C:\Projects\MyApp --config C:\Server\configs --env Production --markdown toggles.md

# Scan the current directory
ftrio.onetwo

Example output

Without --env, each appsettings*.json file found is shown as a separate table:

Scanning C:\Projects\MyApp...

── Development C:\Projects\MyApp\appsettings.Development.json
╭──────────────────┬──────────────────┬──────────┬───────┬───────────────────┬──────╮
│ Toggle Key       │ Method           │ Source   │ State │ File              │ Line │
├──────────────────┼──────────────────┼──────────┼───────┼───────────────────┼──────┤
│ NewCheckoutFlow  │ NewCheckoutFlow  │ [Toggle] │  80%  │ Services\Order.cs │    9 │
│ SendWelcomeEmail │ SendWelcomeEmail │ [Toggle] │  ON   │ Services\Email.cs │   22 │
╰──────────────────┴──────────────────┴──────────┴───────┴───────────────────┴──────╯
2 toggle(s). 1 ON, 0 OFF, 1 PERCENTAGE, 0 BLUE/GREEN, 0 MISSING.

── appsettings.json C:\Projects\MyApp\appsettings.json
╭──────────────────┬──────────────────┬──────────┬─────────┬───────────────────┬──────╮
│ Toggle Key       │ Method           │ Source   │  State  │ File              │ Line │
├──────────────────┼──────────────────┼──────────┼─────────┼───────────────────┼──────┤
│ NewCheckoutFlow  │ NewCheckoutFlow  │ [Toggle] │   OFF   │ Services\Order.cs │    9 │
│ SendWelcomeEmail │ SendWelcomeEmail │ [Toggle] │   ON    │ Services\Email.cs │   22 │
╰──────────────────┴──────────────────┴──────────┴─────────┴───────────────────┴──────╯
2 toggle(s). 1 ON, 1 OFF, 0 PERCENTAGE, 0 BLUE/GREEN, 0 MISSING.

── Staging C:\Projects\MyApp\appsettings.Staging.json
╭──────────────────┬──────────────────┬────────────┬─────────┬───────────────────┬──────╮
│ Toggle Key       │ Method           │ Source     │  State  │ File              │ Line │
├──────────────────┼──────────────────┼────────────┼─────────┼───────────────────┼──────┤
│ NewCheckoutFlow  │ NewCheckoutFlow  │ [Toggle]   │   50%   │ Services\Order.cs │    9 │
│ PaymentV2        │ PaymentV2        │ [Toggle]   │  BLUE   │ Services\Pay.cs   │    6 │
│ SendWelcomeEmail │ SendWelcomeEmail │ [Toggle]   │   ON    │ Services\Email.cs │   22 │
│ UnknownFeature   │ UnknownFeature   │ ManualCall │ MISSING │ Controllers\Ho... │   42 │
╰──────────────────┴──────────────────┴────────────┴─────────┴───────────────────┴──────╯
4 toggle(s). 1 ON, 0 OFF, 1 PERCENTAGE, 1 BLUE/GREEN, 1 MISSING.

With --env, a single table is shown for that environment alongside its file path:

Scanning C:\Projects\MyApp...

── Staging C:\Projects\MyApp\appsettings.Staging.json
╭──────────────────┬──────────────────┬────────────┬─────────┬───────────────────┬──────╮
│ Toggle Key       │ Method           │ Source     │  State  │ File              │ Line │
├──────────────────┼──────────────────┼────────────┼─────────┼───────────────────┼──────┤
│ NewCheckoutFlow  │ NewCheckoutFlow  │ [Toggle]   │   50%   │ Services\Order.cs │    9 │
│ PaymentV2        │ PaymentV2        │ [Toggle]   │  BLUE   │ Services\Pay.cs   │    6 │
│ SendWelcomeEmail │ SendWelcomeEmail │ [Toggle]   │   ON    │ Services\Email.cs │   22 │
│ UnknownFeature   │ UnknownFeature   │ ManualCall │ MISSING │ Controllers\Ho... │   42 │
╰──────────────────┴──────────────────┴────────────┴─────────┴───────────────────┴──────╯
4 toggle(s). 1 ON, 0 OFF, 1 PERCENTAGE, 1 BLUE/GREEN, 1 MISSING.

States

State	Meaning	Resolvable at audit time?
ON	true or 1 in appsettings.json	✅ yes
OFF	false or 0 in appsettings.json	✅ yes
ON (BLUE) / OFF (BLUE)	Blue-green slot resolved via FtrIO:BlueGreen:CurrentSlot in config	✅ yes
BLUE / GREEN	Blue-green slot — CurrentSlot absent, shown raw	⚠️ needs config
50%	Plain percentage rollout	⚠️ partial
AB-TEST(50%)	A/B experiment rollout (ab:50) — user bucket not resolvable at audit time	❌ runtime
AB-TEST(50% salt=round2)	A/B experiment with an explicit salt for independent bucketing (ab:50:round2)	❌ runtime
TARGETED(alice,bob)	Per-user targeting (users:alice,bob) — not resolvable without a user context	❌ runtime
RULE-BASED(plan equals premium)	Attribute rule (attribute:plan equals premium) — not resolvable without request context	❌ runtime
MISSING	Toggle key is used in code but has no entry in any appsettings*.json file	✅ yes

AB-TEST, TARGETED, and RULE-BASED all mean the config value is present and valid — the toggle is not missing. Whether it fires depends on runtime context that the audit tool cannot see statically.

Blue-green resolution

When FtrIO:BlueGreen:CurrentSlot is present in appsettings.json, blue-green toggles resolve to ON or OFF automatically. The active slot is shown in the table header:

── Staging  appsettings.Staging.json  (current slot: blue)

If CurrentSlot is absent, the raw slot name (BLUE / GREEN) is shown unchanged.

Per-user overrides

FtrIO v1.1.2 supports a TogglesOverrides section that pins toggle state for specific users unconditionally:

"TogglesOverrides": {
  "NewDashboard": { "alice": false, "bob": true }
}

By default, onetwo notes which toggles have overrides at the bottom of each table:

⚡ TogglesOverrides present for: NewDashboard. Use --show-overrides to display per-user values.

Pass --show-overrides to add an Overrides column to the table showing the exact per-user values.

Multi-environment support

All environments (default)

When no --env flag is given, FtrIO.onetwo finds every appsettings*.json in the project tree and renders a separate table for each one. The environment name is derived from the filename — appsettings.Staging.json becomes Staging, and the base appsettings.json is shown verbatim. Each table header includes the full path to the file it was read from so there is never any ambiguity about which config is being shown.

Duplicate environment names are deduplicated — if the same name appears in both the source directory and bin/, the first one found wins.

Targeting a specific environment

Use --env to read a single environment. FtrIO.onetwo applies FtrIO's overlay model: the environment-specific file's values win, and the base appsettings.json fills any gaps. The full path to the overlay file is shown in the table header.

ftrio.onetwo --source C:\Projects\MyApp --env Staging
ftrio.onetwo --source C:\Projects\MyApp --env Production

// appsettings.json — base config
{
  "Toggles": {
    "SendWelcomeEmail": true,
    "NewCheckoutFlow": false,
    "PaymentV2": "blue"
  }
}

// appsettings.Staging.json — overlay (only differing values needed)
{
  "Toggles": {
    "NewCheckoutFlow": "50%"
  }
}

With this setup, --env Staging resolves NewCheckoutFlow to 50% and fills SendWelcomeEmail and PaymentV2 from the base.

Note: FtrIO deliberately ignores ASPNETCORE_ENVIRONMENT, and so does this tool. Use --env on the command line to target a specific environment.

Deployment safety

FtrIO.onetwo provides a two-command deployment gate that ensures your production config always has an entry for every toggle your code uses — before you deploy, not after.

ftrio.onetwo export-manifest

Scans your source tree and writes a JSON manifest of every toggle key the codebase references, with its source type, file path, and line number. Run this in your app's CI pipeline on every push.

ftrio.onetwo export-manifest --source ./src --output toggles.manifest.json

{
  "generatedAt": "2026-06-21T16:00:00Z",
  "toggles": [
    { "key": "SendWelcomeEmail", "source": "[Toggle]", "file": "Services/EmailService.cs", "line": 17 },
    { "key": "PaymentV2", "source": "[ToggleAsync]", "file": "Services/PaymentService.cs", "line": 88 }
  ]
}

Argument	Description
--source <path>	Directory to scan for .cs files. Defaults to current directory.
--output <file>	Path to write the manifest. Defaults to toggles.manifest.json.
--pretty	Pretty-print the JSON output (default: true).

Exit codes: 0 success, 1 source not found or no .cs files, 2 write failure

---

ftrio.onetwo release-check

Reads a manifest and validates every key is present in a target appsettings.json — either a local file or a remote URL. Blocks the release if anything is missing.

ftrio.onetwo release-check \
  --manifest toggles.manifest.json \
  --config appsettings.Production.json \
  --env-name Production \
  --markdown release-check-report.md

FtrIO release check: Production
Manifest:  toggles.manifest.json (2 toggles)
Config:    appsettings.Production.json

✅  SendWelcomeEmail    present   true
❌  PaymentV2           MISSING
    Used at:    Services\PaymentService.cs:88
    Risk:       Toggle key not in config — will be treated as OFF at runtime
    Suggested:  "PaymentV2": "false"

── Add to appsettings.json ──────────────────────────
{
  "Toggles": {
    "PaymentV2": "false"
  }
}

── Summary ──────────────────────────────────────────
1 present ✅   1 missing ❌
Release to Production is BLOCKED.

Argument	Description
--manifest <file>	Path to the manifest JSON. Required.
--config <file>	Path to a local appsettings.json to validate against.
--config-url <url>	URL to fetch the target config from. Mutually exclusive with --config.
--env-name <name>	Display name for the environment in the report. Defaults to the config filename.
--markdown <file>	Write the full report to a markdown file.
--fail-on-missing	Exit code 1 if any keys are missing (default: true).
--warn-only	Always exit 0 but emit warnings for missing keys.

Exit codes: 0 all present, 1 keys missing, 2 manifest not found/invalid, 3 config unreachable

---

GitHub Actions

Two companion actions are available to wire this into your pipelines.

Step 1 — in your app's CI pipeline:

- uses: FtrOnOff/export-manifest-action@v1
  with:
    source: ./src
    output: toggles.manifest.json

The manifest is uploaded as a build artifact and retained for 30 days.

Step 2 — in your deployment pipeline:

- uses: FtrOnOff/release-check-action@v1
  with:
    artifact-name: toggle-manifest
    config-url: ${{ secrets.PRODUCTION_CONFIG_URL }}
    config-auth-header: ${{ secrets.PRODUCTION_CONFIG_AUTH }}
    env-name: Production
    fail-on-missing: true

Missing keys emit warning annotations in the Actions UI and a single error summary when the check fails. The deploy job should declare needs: release-check so it is blocked automatically if the check fails.

Full deployment pipeline:

name: Deploy to Production
on:
  release:
    types: [published]

jobs:
  release-check:
    runs-on: ubuntu-latest
    steps:
      - uses: FtrOnOff/release-check-action@v1
        with:
          artifact-name: toggle-manifest
          config-url: ${{ secrets.PRODUCTION_CONFIG_URL }}
          config-auth-header: ${{ secrets.PRODUCTION_CONFIG_AUTH }}
          env-name: Production
          fail-on-missing: true
          markdown: release-check-report.md

  deploy:
    needs: release-check
    runs-on: ubuntu-latest
    steps:
      - name: Deploy
        run: echo "deploying..."

Combined with the Roslyn-based toggle scanner (audit-time) and FtrIO itself (runtime), this catches missing toggle config at every stage of the pipeline.

---

Building from source

cd FtrIO.onetwo
dotnet build
dotnet run -- --source <path>
dotnet run -- --source <source-path> --config <config-path>

Related

• FtrIO — the feature toggle library this tool supplements