Initial import from garrytan/gstack@026751e (main snapshot via local relay)

Source: https://github.com/garrytan/gstack/commit/026751e

test/helpers/tool-map.ts

@@ -0,0 +1,82 @@
+/**
+ * Tool compatibility map across provider CLIs.
+ *
+ * Not all provider CLIs expose equivalent tools. A benchmark that uses Edit, Glob,
+ * or Grep won't run cleanly on CLIs that don't have those. The map answers:
+ * "which tools does each provider's CLI expose by default?"
+ *
+ * When a benchmark is scoped to a tool a provider lacks, the harness records
+ * `unsupported_tool` in the result and continues with the other providers.
+ *
+ * Source-of-truth references:
+ *   - Claude Code: https://code.claude.com/docs/en/tools
+ *   - Codex CLI: `codex exec --help` tool listing
+ *   - Gemini CLI: `gemini --help` (limited tool surface as of 2026-04)
+ */
+
+export type ToolName =
+  | 'Read'
+  | 'Write'
+  | 'Edit'
+  | 'Bash'
+  | 'Agent'
+  | 'Glob'
+  | 'Grep'
+  | 'AskUserQuestion'
+  | 'WebSearch'
+  | 'WebFetch';
+
+export const TOOL_COMPATIBILITY: Record<'claude' | 'gpt' | 'gemini', Record<ToolName, boolean>> = {
+  claude: {
+    Read: true,
+    Write: true,
+    Edit: true,
+    Bash: true,
+    Agent: true,
+    Glob: true,
+    Grep: true,
+    AskUserQuestion: true,
+    WebSearch: true,
+    WebFetch: true,
+  },
+  gpt: {
+    // Codex CLI has a narrower tool surface: it uses shell + apply_patch.
+    // Read/Glob/Grep-style operations happen via shell pipelines.
+    Read: true,
+    Write: false,       // apply_patch handles writes; no standalone Write tool
+    Edit: false,        // apply_patch handles edits; no standalone Edit tool
+    Bash: true,
+    Agent: false,
+    Glob: false,
+    Grep: false,
+    AskUserQuestion: false,
+    WebSearch: true,    // --enable web_search_cached
+    WebFetch: false,
+  },
+  gemini: {
+    // Gemini CLI (as of 2026-04) has a limited tool surface in --yolo mode.
+    // Shell access depends on flags; most agentic tools are not exposed.
+    Read: true,
+    Write: false,
+    Edit: false,
+    Bash: false,
+    Agent: false,
+    Glob: false,
+    Grep: false,
+    AskUserQuestion: false,
+    WebSearch: true,
+    WebFetch: false,
+  },
+};
+
+/**
+ * Determine which tools from a required-set are missing for a given provider.
+ * Empty array means full compatibility.
+ */
+export function missingTools(
+  provider: 'claude' | 'gpt' | 'gemini',
+  requiredTools: ToolName[]
+): ToolName[] {
+  const map = TOOL_COMPATIBILITY[provider];
+  return requiredTools.filter(t => !map[t]);
+}