Charles Local MCP

charles-local-mcp

Local-only, profile-driven Charles Proxy automation for macOS. The same application service is exposed through a JSON CLI and an MCP stdio server.

Version 0.1.3 supports Charles 4.6.8 on macOS. The public package contains only generic example.com fixtures and no organization-specific hosts or paths.

Profile

schemaVersion = 1

[profiles.demo] sourceHost = "app.example.com" sourcePath = "/api*" # optional Charles path pattern destinationUrl = "http://127.0.0.1:8080" sslHosts = ["app.example.com"] verificationUrl = "https://app.example.com/health"

Omit destinationUrl for a proxy-only profile that disables Map Remote while retaining the exact SSL hosts and optional verification URL. When present, destinationUrl is restricted to loopback addresses.

Map Remote destinations must resolve to a loopback host. verificationUrl is optional, must use HTTPS without embedded credentials, and must match sourceHost.

Commands

charles-local-mcp doctor --json

charles-local-mcp --profiles-file profiles.toml profiles validate --json charles-local-mcp --profiles-file profiles.toml --evidence-root /absolute/path/exports session evidence --profile demo --xml-file session.xml --json charles-local-mcp --profiles-file profiles.toml setup plan --profile demo --platform android --json charles-local-mcp --profiles-file profiles.toml setup apply --token TOKEN --json charles-local-mcp setup resume --token TOKEN --json charles-local-mcp status --json charles-local-mcp cleanup plan --json charles-local-mcp cleanup apply --token TOKEN --json charles-local-mcp serve

State defaults to ~/Library/Application Support/charles-local-mcp. Tests and integrators can isolate it with CHARLES_LOCAL_MCP_HOME or --state-dir. CLI stdout is JSON only; MCP stdout is protocol only. Diagnostics use stderr.

Mutation commands require macOS and Charles 4.6.8. Setup and cleanup plans expire after 15 minutes, are single-use, and are rejected if state changed. Only one active session is allowed in a state directory.

Local XML session evidence

session evidence reads only a selected local .xml file inside the configured --evidence-root and the selected immutable profile. If the option is omitted, the root defaults to /evidence; it is resolved only when evidence analysis is requested, so existing setup and inspection commands do not require that directory. Relative traversal and absolute paths outside the root are rejected without returning local paths. The evidence root, parent directories, and selected file must not be symbolic links.

The operation uses the selected profile's exact sourceHost only as an internal filter. The bundle returns the profile name with hostScope: "exact", a fixed HTTP method enum, per-bundle opaque route references such as route-001, query parameter counts, numeric status/duration, and request/response sizes when those attributes exist. Repeated raw paths receive the same opaque route reference within one bundle. Other hosts are excluded and reported only as a count.

The operation never returns raw hosts, paths, query names, query values, headers, cookies, credentials, or bodies. Unknown request methods become the fixed value OTHER. It does not upload or persist the source session and does not write an evidence ledger. Files are limited to 10 MiB and 1,000 transactions; output is limited to 100 requests and 50 failures. DTD, DOCTYPE, and entity references are rejected. Some Charles exports include a DOCTYPE declaration; make a trusted local copy and remove the complete declaration before analysis. See docs/session-evidence.md for the contract, safety boundary, limits, and stable error codes.

The real-device procedure is intentionally manual: see docs/manual-smoke.md.

Install

Build from crates.io when a local Rust toolchain is available:

cargo install charles-local-mcp --locked

For a one-click MCP client installation on macOS, use the universal .mcpb asset from the matching GitHub Release. The native binary and bundle are not signed or notarized by Apple, so macOS may show a security warning when opening a downloaded asset. Verify SHA256SUMS from that release before installing. The bundle asks for a TOML profiles file and starts charles-local-mcp serve; profiles remain read-only to MCP tools. It also asks for the XML evidence folder that is the only directory the session_evidence tool may read.

Release maintainers should follow docs/releasing.md.