Inspector

Inspector is a .NET CLI and runtime infrastructure for inspecting and manipulating Avalonia UI trees. It is designed for both human use and coding-agent automation with deterministic, machine-readable output.

What it does

• Enumerates visual and logical trees
• Reads node property metadata and values
• Applies node/property mutations (set property, insert/remove/move/reparent)
• Exposes capabilities and stable schema metadata for automation
• Supports:
  • Host mode (instrumented runtime in app)
  • Process mode (CLI-side no-host attach via --pid or --name)

NuGet packages

Package	Version	Downloads	Install
Inspector.Contracts			dotnet add package Inspector.Contracts
Inspector.Transport			dotnet add package Inspector.Transport
Inspector.Host			dotnet add package Inspector.Host
Inspector.AvaloniaAdapter			dotnet add package Inspector.AvaloniaAdapter
Inspector.Cli.Tool			dotnet tool install --global Inspector.Cli.Tool

Installation

Library packages

Install the package you need:

dotnet add package Inspector.Contracts
dotnet add package Inspector.Transport
dotnet add package Inspector.Host
dotnet add package Inspector.AvaloniaAdapter

CLI as .NET tool

Global tool:

dotnet tool install --global Inspector.Cli.Tool
inspector --help

Local tool manifest:

dotnet new tool-manifest
dotnet tool install --local Inspector.Cli.Tool
dotnet tool run inspector --help

Update/uninstall:

dotnet tool update --global Inspector.Cli.Tool
dotnet tool uninstall --global Inspector.Cli.Tool

Repository layout

src/
  Inspector.Contracts        Shared DTOs/enums/schema contracts
  Inspector.Transport        Local transport/session/authorization model
  Inspector.Host             In-process host runtime abstractions
  Inspector.AvaloniaAdapter  Tree/property/mutation adapter implementations
  Inspector.Cli              Command-line interface and agent-friendly output
tests/
  Inspector.Tests            xUnit test suite
samples/
  Inspector.SampleApp        Minimal host runtime integration sample

Requirements

• .NET SDK compatible with net10.0

CI build and release scripts

• scripts/ci-build.sh: restore, build, test, and pack all publishable packages.
• scripts/ci-release.sh: runs ci-build.sh and pushes .nupkg/.snupkg to NuGet.
• .github/workflows/ci.yml: PR/push validation + package artifact upload.
• .github/workflows/release.yml: tag/manual release publishing to NuGet (NUGET_API_KEY secret required).

Run locally:

bash scripts/ci-build.sh

Release locally:

NUGET_API_KEY=<your-key> VERSION=0.1.0 bash scripts/ci-release.sh

CLI help (latest)

Inspector.Cli command surface
Usage:
  inspector capabilities
  inspector connect [--mode <stub|host|process>] [--address <uri>] [--pid <int>] [--name <process-name>] [--client-id <id>] [--client-version <version>] [--secret <secret>] [--scope <scope>]...
  inspector tree get --session-id <id> [--kind visual|logical]
  inspector node get-properties --session-id <id> --node-id <id>
  inspector node set-property --session-id <id> --node-id <id> --property <name> --value <json-or-text> [--operation-id <id>]
  inspector tree mutate --session-id <id> --target-node-id <id> --operation <set-property|insert|remove|move|reparent> [--payload <json>] [--dry-run] [--operation-id <id>]
  inspector tree batch-mutate --session-id <id> --operations <json-array|json-object> [--dry-run] [--operation-id <id>]
Global options:
  --json                      Emit deterministic JSON output
  --output <text|json>        Select output mode
  --help, -h                  Show help
Exit codes: 0=success, 2=validation error, 3=execution error, 10=unexpected error

CLI usage examples

# Capabilities
inspector capabilities --json

# Connect (host mode)
inspector connect --mode host --address local://inspector --client-id my-tool --json

# Connect (process mode by pid)
inspector connect --mode process --pid 12345 --json

# Connect (process mode by name)
inspector connect --mode process --name Inspector.SampleApp --json

# Visual tree
inspector tree get --session-id sess-123 --kind visual --json

# Node properties
inspector node get-properties --session-id sess-123 --node-id visual-button --json

# Set property
inspector node set-property --session-id sess-123 --node-id visual-button --property Width --value 320 --json

# Mutate tree (dry-run)
inspector tree mutate --session-id sess-123 --target-node-id visual-button --operation move --payload '{"index":0}' --dry-run --json

# Batch mutate (single call, multiple operations)
inspector tree batch-mutate --session-id sess-123 --operations '[{"targetNodeId":"visual-label","operation":"set-property","payload":{"property":"Text","value":"Welcome back"}},{"targetNodeId":"visual-root","operation":"insert","payload":{"typeName":"TextBox","name":"EmailInput","properties":{"Watermark":"Email"}}}]' --json

If you are developing from source, you can run the same commands with:

dotnet run --project src/Inspector.Cli -- <command> [args]

Host mode full tree mutability payloads

When connected with --mode host, tree mutate supports structural and property mutations with JSON payloads:

• set-property: {"property":"<name>","value":<json>}
• insert: {"typeName":"<type>","nodeId":"<optional-id>","name":"<optional-name>","classes":["..."],"properties":{"...":...},"index":0}
• move: {"index":1}
• reparent: {"parentNodeId":"<node-id>","index":0}
• remove: payload optional

The same operation payloads are also used by tree batch-mutate entries.

Examples:

# Create a new control node under visual-root (nodeId can be omitted for auto-generation)
inspector tree mutate --session-id <session-id> --target-node-id visual-root --operation insert --payload '{"typeName":"Avalonia.Controls.TextBox","name":"EmailInput","properties":{"Text":"","Watermark":"Email"}}' --json

# Set any property via tree mutate payload
inspector tree mutate --session-id <session-id> --target-node-id visual-label --operation set-property --payload '{"property":"Text","value":"Ready to login"}' --json

# Reparent and remove
inspector tree mutate --session-id <session-id> --target-node-id child-node --operation reparent --payload '{"parentNodeId":"new-parent","index":0}' --json
inspector tree mutate --session-id <session-id> --target-node-id old-node --operation remove --json

# Batch mutate using either raw array or { "operations": [...] }
inspector tree batch-mutate --session-id <session-id> --operations '{"operations":[{"targetNodeId":"visual-label","operation":"set-property","payload":{"property":"Text","value":"Ready to login"}},{"targetNodeId":"visual-root","operation":"insert","payload":{"typeName":"Avalonia.Controls.TextBox","name":"EmailInput","properties":{"Watermark":"Email"}}}]}' --json

Process mode guide (--mode process)

Use this mode to target an already-running process by PID or process name.

1. Connect and capture session id:

inspector connect --mode process --pid <pid> --json
# or
inspector connect --mode process --name <process-name> --json

Check data.processSnapshotAvailable in connect output:

• true: live UI snapshot is available
• false: CLI will use fallback process metadata

2. Reuse returned sessionId in follow-up commands:

inspector tree get --session-id <session-id> --kind visual --json
inspector node get-properties --session-id <session-id> --node-id <node-id> --json
inspector node set-property --session-id <session-id> --node-id <node-id> --property <name> --value <json-or-text> --json

For apps that include the sample snapshot publisher integration:

• node set-property queues live property mutation commands for the running process.
• tree mutate in process mode also queues live structural mutation commands (insert, remove, move, reparent, set-property) so runtime controls can be added/rearranged without restarting the app.
• tree batch-mutate applies multiple mutations in one CLI call and queues each live process mutation command in order for faster bulk updates.

3. Common process-mode errors:

• cli.process.not_found: PID/name not found
• cli.process.ambiguous: multiple processes match --name (retry with --pid)
• cli.process.exited: process ended before command execution

When the target app publishes live inspector snapshots (the included Inspector.SampleApp does), process mode returns live visual/logical nodes and node properties instead of fallback process metadata. If no live snapshot is published by the target process, process mode falls back to process metadata nodes.

Session model

• connect creates a session and returns sessionId.
• Session state is persisted across CLI invocations in a local temporary session store.
• tree get, node get-properties, node set-property, tree mutate, and tree batch-mutate require a valid --session-id.

Output behavior

• Defaults to JSON when input/output is redirected (non-interactive)
• Supports explicit output selection via --output text|json
• --json forces deterministic JSON output
• Errors are returned with explicit non-zero exit codes

Agent skill integration (Codex)

Repository includes a single Codex skill definition:

• SKILL/inspector-avalonia-cli/SKILL.md

Install it locally:

mkdir -p ~/.codex/skills/inspector-avalonia-cli
cp SKILL/inspector-avalonia-cli/SKILL.md ~/.codex/skills/inspector-avalonia-cli/SKILL.md

Sample app

samples/Inspector.SampleApp is an Avalonia desktop app (dotnet Avalonia template) with inspector host wiring via InspectorHostRuntime and DelegateInspectorRequestHandler.

Run it with:

dotnet run --project samples/Inspector.SampleApp

Then connect from CLI in host mode:

inspector connect --mode host --address local://inspector --json

Current implementation status

This repository includes a functioning foundation (contracts, transport model, host runtime, adapter services, CLI, tests, sample app), including process-mode connection via --pid/--name and session-aware CLI workflows.