Crate rtk_mcp_agy 

Shared logic for the rtk-mcp-agy plugin.

Everything here is pure: JSON-RPC dispatch, response shaping, and the PreInvocation payload. The two binaries in src/bin/ only move bytes and spawn processes.

The split exists because the interesting behaviour is otherwise unreachable by a test. handle_line takes the rewriter and the executor as closures, so the tools/call path — which in production shells out to rtk and then to a shell — can be exercised on a machine that has neither installed, and its failure modes can be forced rather than waited for.

The seam earned itself immediately: it is what made the hardcoded pwsh visible as a portability bug (see resolve_shell) rather than something only a Linux user would ever discover.

Macros

plugin_name 🔒

The plugin ID in plugin.json, and the plugin’s directory name in Antigravity.

server_name 🔒

The server key registered in mcp_config.json.

Structs

PreInvocationOutput

The payload the PreInvocation hook writes to stdout.

Enums

Execution

The outcome of trying to run a command.

Constants

AGY_SERVER_NAME

The namespaced server name Antigravity assigns to this plugin’s MCP server.

DEFAULT_RTK_BIN

The rtk executable, when RTK_BIN says nothing.

DEFAULT_UNIX_SHELL

The shell used to run commands everywhere else.

DEFAULT_WINDOWS_SHELL

The shell used to run commands on Windows.

METHOD_NOT_FOUND

JSON-RPC’s “method not found”.

PLUGIN_NAME

The plugin directory / ID in Antigravity.

PROTOCOL_VERSION

The MCP protocol revision spoken by this server.

SERVER_NAME

The server name an MCP client sees, and the key mcp_config.json registers.

TOOL_CHECK

Show how rtk would rewrite a shell command without running it.

TOOL_DISCOVER

Analyze past session history for missed token savings.

TOOL_GAIN

Report rtk token savings.

TOOL_NAME

Run an rtk-optimized command.

Functions

build_check_command

Build the command line for rtk hook check.

build_discover_command

Build the command line for rtk discover.

build_gain_command

Build the command line for rtk gain.

call_arguments

Pull CommandLine and Cwd out of a tools/call request.

dispatch_request

Dispatch a parsed JSON-RPC request to the appropriate method handler.

envelope 🔒

Wrap a result body in its JSON-RPC envelope.

extract_cwd

Extract the Cwd argument or fall back to ".".

format_execution

Render an execution as the tools/call result body.

handle_line

Handle one line of input, returning the response to write — or None when the server must stay silent.

handle_request

Handle a parsed JSON-RPC request using default fallback closures.

method_not_found

The body used for an unrecognised method.

non_blank 🔒

Trim a value, discarding it if nothing is left.

parse_rewrite

Interpret the stdout of rtk rewrite.

preinvocation_payload

Build the injected instruction that steers the model onto the MCP tool.

resolve_rtk_bin

Decide which rtk executable to invoke.

resolve_shell

Decide which shell runs the rewritten command.

server_info

The initialize result.

shell_quote

Quote a string safely for inclusion in a shell command line.

tools_list

The tools/list result advertising all 4 tools.

validate_format 🔒

version

The crate version, and the single source for every place one is reported.