mcp-proxy 0.3.1

# Testing Sandbox Proxy
#
# Isolated environment for testing MCP integrations. Uses in-process
# channel backends and stdio mocks. Safe to run in CI with no external
# dependencies.
#
# See: docs/architectures.md #9

[proxy]
name = "test-sandbox"
version = "1.0.0"
separator = "/"
instructions = "Testing sandbox. All backends are mocked or sandboxed."

[proxy.listen]
host = "127.0.0.1"
port = 0  # OS-assigned port for test isolation

# --- Backends ---

# Mock filesystem with read-only access to test fixtures
[[backends]]
name = "fs"
transport = "stdio"
command = "npx"
args = ["-y", "@modelcontextprotocol/server-filesystem", "--read-only", "./test-fixtures"]

[backends.timeout]
seconds = 5

# Mock database -- read-only SQLite for deterministic test data
[[backends]]
name = "db"
transport = "stdio"
command = "/usr/local/bin/db-mcp-server"
args = ["--read-only", "--connection-string", "sqlite:./test-fixtures/test.db"]
expose_tools = ["query"]

[backends.timeout]
seconds = 5

[backends.concurrency]
max_concurrent = 1

# Echo server for integration testing -- returns inputs as outputs
[[backends]]
name = "echo"
transport = "stdio"
command = "/usr/local/bin/echo-mcp-server"

[backends.timeout]
seconds = 2

[backends.retry]
max_retries = 0

# Slow/flaky backend for resilience testing
[[backends]]
name = "flaky"
transport = "http"
url = "http://localhost:9999"

[backends.timeout]
seconds = 2

[backends.retry]
max_retries = 3
initial_backoff_ms = 50
max_backoff_ms = 500

[backends.circuit_breaker]
failure_rate_threshold = 0.5
minimum_calls = 3
wait_duration_seconds = 5

# --- Observability ---

[observability]
audit = true
log_level = "debug"

[security]
max_argument_size = 1048576