install writes an unsupported `args` key into the Claude Code SubagentStart hook, so it never runs

[dergachoff]

Problem

The SubagentStart hook cbm installs never runs — every subagent start stalls to the hook timeout and returns no graph context.

Evidence

install -y writes this into ~/.claude/settings.json:

{ "type": "command", "command": "/Users/me/.local/bin/codebase-memory-mcp", "args": ["hook-augment"], "timeout": 5 }

Claude Code's hook schema has no args — in the published settings schema, hookCommand is additionalProperties: false and takes type, command, timeout and async. So the subcommand is dropped and the bare binary runs, which is the MCP stdio server: it waits on stdin and never exits. I piped a SubagentStart payload into it and it was still running at 6s; the same payload into codebase-memory-mcp hook-augment returns in 2s.

Expected fix

The entry that was there before (from 0.9.1-rc.1) pointed at the installed cbm-subagent-reminder wrapper, which does the right thing. Either restore that, or put the subcommand in the command string: "<bin> hook-augment".

v0.11.0, macOS arm64, Claude Code 2.1.278. Same family as #1737, different client.

[DeusData]

Thank you for tracing this down to the installed hook entry and comparing it with the explicit hook-augment invocation. I checked current main (59a05eb): cbm_upsert_claude_subagent_hooks_with_binary does place the binary in command and the subcommand in a separate argument array, matching the shape you reported.

We are tracking this as a high-priority Claude Code integration bug. The next review needs to verify the generated entry against the actual client hook contract, including paths with spaces and migration of already-installed entries. This should stay separate from #1335's warm-daemon/deadline behavior: a command-launch contract failure must be addressed before tuning its runtime deadline. No further reproduction is needed for initial triage; thank you for the concrete evidence.

Code checked:

codebase-memory-mcp/src/cli/cli.c

Lines 6075 to 6120 in 59a05eb

	static int cbm_upsert_claude_subagent_hooks_with_binary(const char *settings_path,
	const char *binary_path) {
	char shell_command[CLI_BUF_8K];
	char previous_command[CLI_BUF_8K];
	char released_command[CLI_BUF_8K];
	char previous_legacy_command[CLI_BUF_8K];
	char released_legacy_command[CLI_BUF_8K];
	if (cbm_resolve_hook_command(CMM_SUBAGENT_REMINDER_SCRIPT, shell_command,
	sizeof(shell_command)) != CLI_OK ||
	cbm_resolve_previous_hook_command(CMM_SUBAGENT_REMINDER_SCRIPT, previous_command,
	sizeof(previous_command)) != CLI_OK ||
	cbm_resolve_released_hook_command(CMM_SUBAGENT_REMINDER_SCRIPT, released_command,
	sizeof(released_command)) != CLI_OK ||
	cbm_resolve_previous_hook_command(CMM_SUBAGENT_REMINDER_SCRIPT_LEGACY,
	previous_legacy_command,
	sizeof(previous_legacy_command)) != CLI_OK ||
	cbm_resolve_released_hook_command(CMM_SUBAGENT_REMINDER_SCRIPT_LEGACY,
	released_legacy_command,
	sizeof(released_legacy_command)) != CLI_OK) {
	return CLI_ERR;
	}
	const char *command = binary_path && binary_path[0] ? binary_path : shell_command;
	const char *const *command_args = binary_path && binary_path[0] ? cmm_claude_exec_args : NULL;
	size_t command_arg_count = binary_path && binary_path[0]
	? sizeof(cmm_claude_exec_args) / sizeof(cmm_claude_exec_args[0])
	: 0U;
	const char *const old_commands[] = {shell_command, released_command,
	previous_command, released_legacy_command,
	previous_legacy_command, NULL};
	if (cbm_remove_previous_claude_exec_hook(settings_path, "SubagentStart", "*", NULL,
	binary_path) != CLI_OK) {
	return CLI_ERR;
	}
	/* matcher "*" is the natural choice a user would also pick for their own
	* catch-all SubagentStart hook, so claim ownership by command too — never
	* clobber or remove a foreign "*" entry. */
	return upsert_hooks_json((hooks_upsert_args_t){.settings_path = settings_path,
	.hook_event = "SubagentStart",
	.matcher_str = "*",
	.command_str = command,
	.command_args = command_args,
	.command_arg_count = command_arg_count,
	.old_commands = old_commands,
	.timeout_value = CMM_HOOK_TIMEOUT_SEC,
	.match_command_exact = command});
	}