/**
 * The tool call's own directory, read from a hook payload.
 *
 * A relative target path belongs to the directory the tool call RUNS in: the
 * file a call writes is the one that directory names, not the one the project
 * root would name. The gate needs that directory to say which file a payload
 * really points at, and the payload is where a harness states it.
 *
 * The read is deliberately narrow — one key, at the top level, holding a
 * string. A `cwd` nested inside the tool's own arguments is an ARGUMENT the
 * tool was handed, not the directory the call runs in, so only the top-level
 * key counts.
 *
 * The absence of the key is not an error: the caller then uses the process's
 * own working directory, which is the same directory whenever the harness runs
 * the hook where the tool call runs.
 */
export declare function readToolCallCwd(payload: Readonly<Record<string, unknown>>): string | null;
/**
 * The directory a relative target path is read against.
 *
 * The payload's own `cwd` is the base only when it is a USABLE one: an
 * absolute path naming an existing directory inside the project the caller
 * named. A `cwd` that is missing, relative, names a file, names a directory
 * that is not there, or names a directory outside the project is not a
 * directory this project can judge the file against — and a base that is not
 * the call's own directory resolves the path against the wrong tree, which is
 * how an edit into a hard-blocked family slipped through.
 *
 * The rule ASSUMES the tool call runs inside the named project, which is
 * where the gate is installed. When it does not, the payload `cwd` is
 * rejected and the path is read against the gate's own working directory
 * instead — a different tree.
 *
 * While the base the path is read against IS the call's own directory, the
 * error stays one-directional: a file that lies outside every family can be
 * denied, and never the other way round — a wrongly allowed edit is a hole,
 * a wrongly refused one is an inconvenience. That direction is NOT a general
 * property of the fallback: when the base is the gate's own working
 * directory and the call runs somewhere else, the call's relative path is
 * read against a tree that is not the call's, and a file that really is
 * inside a hard-blocked family can be ALLOWED.
 * Measured 2026-10-23; backlog §19.3.
 *
 * The fallback is the gate process's own working directory: that is where the
 * hook runs, and in the normal invocation it IS the tool call's directory.
 * The gate does not fail closed here — it uses the best base it has, and a
 * file that lands outside the project is judged by its spelling, which never
 * widens the gate.
 */
export declare function resolveToolCallBaseDir(payload: Readonly<Record<string, unknown>>, projectRoot: string, fallback: string): string;