D — 130 Operations for AI Agents

This page is the canonical reference an AI coding agent uses to refactor, query, and analyze D code through the act MCP server. 130 operations available: 56 refactor, 18 query, 42 analysis, 14 verification. Each operation is callable from Claude Code, Cursor, Codex, OpenCode, or any MCP-compatible agent host. Click any operation for a stable anchor link suitable for citation.

Worked D examples

act101 applies D-specific idioms directly to a source file. It can wrap a resource's cleanup in a scope(exit) block, rewrite a C-style index for loop as a foreach over the array, and generate an opEquals method that compares every field of a struct or class. The generated opEquals compares fields in declaration order and returns false on the first mismatch, matching the short-circuit comparison a hand-written equality check would use. Each example below is the verbatim output of the command shown, run against the file shown.

Add a scope guard for resource cleanup

resource.d opens a file and writes to it, but never closes it if write throws.

$ act refactor-lang add_scope_guard_d --file resource.d --params '{"line":2,"cleanup_code":"f.close();","scope_kind":"exit","column":1}'

Before

void foo() {
    auto f = File("x");
    f.write("hello");
}

After

void foo() {
    auto f = File("x");
    scope(exit) {
        f.close();
    }
    f.write("hello");
}

A scope(exit) { f.close(); } block is inserted right after f is opened, so f.close() runs when foo exits, however it exits.

Convert an index loop to foreach

app.d's main walks arr with a C-style for loop whose index i exists only to read arr[i].

$ act refactor-lang convert_for_to_foreach_d --file app.d --params '{"line":6,"column":5}'

Before

module app;
import std.stdio;

void main() {
    int[] arr = [1, 2, 3, 4, 5];
    for (int i = 0; i < arr.length; i++) {
        writeln(arr[i]);
    }
}

After

module app;
import std.stdio;

void main() {
    int[] arr = [1, 2, 3, 4, 5];
    foreach (i, item; arr) {
        writeln(arr[i]);
    }
}

The for header becomes foreach (i, item; arr), D's range-based form with the index kept; the loop body is left as written, so arr[i] still reads through i.

Generate an opEquals method from a class's fields

color.d declares Color with three fields — r, g, b — but no way to compare two instances for equality.

$ act refactor-lang generate_equals_method_d --file color.d --params '{"line":3,"column":7}'

Before

module models;

class Color {
    int r;
    int g;
    int b;
}

After

module models;

class Color {
    int r;
    int g;
    int b;

    bool opEquals(const typeof(this) other) const {
        if (this.r != other.r) return false;
        if (this.g != other.g) return false;
        if (this.b != other.b) return false;
        return true;
    }
}

A bool opEquals(const typeof(this) other) const method is appended that compares r, g, and b in turn and returns false on the first mismatch, true if all three match.

Query

18 query tools, the same on every supported language. Descriptions live in the shared reference: /docs/query-tools.

callers control_flow data_flow definition diagnostics effect_closure effect_summary fix_auto get_type graph import_organize interface mutations references repo_outline skeleton symbols symbols_batch

Refactor

Analysis

42 analysis tools, the same on every supported language. Descriptions live in the shared reference: /docs/analysis-tools.

analyze_api_diff analyze_chokepoints analyze_clones analyze_clusters analyze_cohesion analyze_conformance analyze_coupling analyze_cycle_risk analyze_cycles analyze_dead_code analyze_depth analyze_entry_points analyze_export analyze_extraction analyze_fan_balance analyze_features analyze_hotspots analyze_impact analyze_inconsistencies analyze_inheritance analyze_interface_bloat analyze_interfaces analyze_layers analyze_orphan_types analyze_patterns analyze_platform_deps analyze_readiness analyze_roles analyze_seams analyze_stability analyze_surface analyze_test_gaps analyze_thickness analyze_type_completeness churn_hotspots co_change_clusters coverage_overlay ownership_map profile_overlay simulate split_module trace_overlay

Verify

14 verify tools, the same on every supported language. Descriptions live in the shared reference: /docs/verification.

bisect_regression gate generate_test_harness scan secret_surface summarize_pr taint_flow unsafe_surface verify_behavioral_equivalence verify_contract_preserved verify_diff_semantics verify_port_parity verify_side_effects verify_test_impact