diff --git a/packages/coding-agent/src/cli/args.ts b/packages/coding-agent/src/cli/args.ts
index af0414068..a52f1530b 100644
--- a/packages/coding-agent/src/cli/args.ts
+++ b/packages/coding-agent/src/cli/args.ts
@@ -5,7 +5,7 @@ import { type Effort, THINKING_EFFORTS } from "@oh-my-pi/pi-ai";
 import { APP_NAME, CONFIG_DIR_NAME, logger } from "@oh-my-pi/pi-utils";
 import chalk from "chalk";
 import { parseEffort } from "../thinking";
-import { BUILTIN_TOOLS } from "../tools";
+import { BUILTIN_TOOL_NAMES } from "../tools/builtin-names";
 import {
 	OPTIONAL_FLAGS,
 	OPTIONAL_VALUE_FLAGS,
@@ -72,8 +72,8 @@ export interface Args {
 const PARSE_DEPS: ParseDeps = {
 	logger,
 	parseEffort,
-	BUILTIN_TOOLS,
-	THINKING_EFFORTS,
+	builtinToolNames: BUILTIN_TOOL_NAMES,
+	thinkingEfforts: THINKING_EFFORTS,
 };
 
 export function parseArgs(inputArgs: string[], extensionFlags?: Map<string, { type: "boolean" | "string" }>): Args {
diff --git a/packages/coding-agent/src/cli/completion-gen.ts b/packages/coding-agent/src/cli/completion-gen.ts
index 33e8b0458..60aecbc17 100644
--- a/packages/coding-agent/src/cli/completion-gen.ts
+++ b/packages/coding-agent/src/cli/completion-gen.ts
@@ -15,7 +15,7 @@
  * knob and is keyed by flag name so it stays stable as flags are added.
  */
 import type { ArgDescriptor, CliConfig, CommandCtor, FlagDescriptor } from "@oh-my-pi/pi-utils/cli";
-import { BUILTIN_TOOLS } from "../tools";
+import { BUILTIN_TOOL_NAMES } from "../tools/builtin-names";
 
 export type Shell = "bash" | "zsh" | "fish";
 
@@ -77,7 +77,7 @@ function flagValue(name: string, desc: FlagDescriptor): ValueSource {
 	if (MODEL_FLAGS[name]) return { kind: "models", multiple: false };
 	if (name === "models") return { kind: "models", multiple: true };
 	if (SESSION_FLAGS[name]) return { kind: "sessions" };
-	if (name === "tools") return { kind: "list", values: Object.keys(BUILTIN_TOOLS) };
+	if (name === "tools") return { kind: "list", values: BUILTIN_TOOL_NAMES };
 	if (DIR_FLAGS[name]) return { kind: "dir" };
 	if (desc.kind === "integer") return { kind: "value" };
 	return { kind: "file" };
diff --git a/packages/coding-agent/src/cli/flag-tables.ts b/packages/coding-agent/src/cli/flag-tables.ts
index 0be7b2717..c078b5e04 100644
--- a/packages/coding-agent/src/cli/flag-tables.ts
+++ b/packages/coding-agent/src/cli/flag-tables.ts
@@ -47,8 +47,8 @@ import type { Args } from "./args";
 export interface ParseDeps {
 	logger: { warn: (message: string, meta?: Record<string, unknown>) => void };
 	parseEffort: (value: string | null | undefined) => Effort | undefined;
-	BUILTIN_TOOLS: Record<string, unknown>;
-	THINKING_EFFORTS: readonly string[];
+	builtinToolNames: readonly string[];
+	thinkingEfforts: readonly string[];
 }
 
 export type StringSetter = (result: Args, value: string, deps: ParseDeps) => void;
@@ -146,12 +146,12 @@ export const STRING_SETTERS: Record<string, StringSetter> = {
 			.filter(Boolean);
 		const valid: string[] = [];
 		for (const name of names) {
-			if (name in deps.BUILTIN_TOOLS) {
+			if (deps.builtinToolNames.includes(name)) {
 				valid.push(name);
 			} else {
 				deps.logger.warn("Unknown tool passed to --tools", {
 					tool: name,
-					validTools: Object.keys(deps.BUILTIN_TOOLS),
+					validTools: deps.builtinToolNames,
 				});
 			}
 		}
@@ -164,7 +164,7 @@ export const STRING_SETTERS: Record<string, StringSetter> = {
 		} else {
 			deps.logger.warn("Invalid thinking level passed to --thinking", {
 				level: value,
-				validThinkingLevels: deps.THINKING_EFFORTS,
+				validThinkingLevels: deps.thinkingEfforts,
 			});
 		}
 	},
diff --git a/packages/coding-agent/src/tools/builtin-names.ts b/packages/coding-agent/src/tools/builtin-names.ts
new file mode 100644
index 000000000..853c24ec0
--- /dev/null
+++ b/packages/coding-agent/src/tools/builtin-names.ts
@@ -0,0 +1,33 @@
+export const BUILTIN_TOOL_NAMES = [
+	"read",
+	"bash",
+	"edit",
+	"ast_grep",
+	"ast_edit",
+	"render_mermaid",
+	"ask",
+	"debug",
+	"eval",
+	"ssh",
+	"github",
+	"find",
+	"search",
+	"lsp",
+	"inspect_image",
+	"browser",
+	"checkpoint",
+	"rewind",
+	"task",
+	"job",
+	"irc",
+	"todo_write",
+	"web_search",
+	"search_tool_bm25",
+	"write",
+	"memory_edit",
+	"retain",
+	"recall",
+	"reflect",
+] as const;
+
+export type BuiltinToolName = (typeof BUILTIN_TOOL_NAMES)[number];
diff --git a/packages/coding-agent/src/tools/index.ts b/packages/coding-agent/src/tools/index.ts
index 973823980..a8bb4ec8f 100644
--- a/packages/coding-agent/src/tools/index.ts
+++ b/packages/coding-agent/src/tools/index.ts
@@ -31,6 +31,7 @@ import { AstEditTool } from "./ast-edit";
 import { AstGrepTool } from "./ast-grep";
 import { BashTool } from "./bash";
 import { BrowserTool } from "./browser";
+import type { BuiltinToolName } from "./builtin-names";
 import { type CheckpointState, CheckpointTool, RewindTool } from "./checkpoint";
 import { DebugTool } from "./debug";
 import { EvalTool } from "./eval";
@@ -295,7 +296,7 @@ export function computeEssentialBuiltinNames(settings: Settings): string[] {
  * Public callable factory map. External callers may invoke `BUILTIN_TOOLS.read(session)` or
  * `BUILTIN_TOOLS[name](session)` to construct a tool directly.
  */
-export const BUILTIN_TOOLS: Record<string, ToolFactory> = {
+export const BUILTIN_TOOLS: Record<BuiltinToolName, ToolFactory> = {
 	read: s => new ReadTool(s),
 	bash: s => new BashTool(s),
 	edit: s => new EditTool(s),
@@ -335,7 +336,7 @@ export const HIDDEN_TOOLS: Record<string, ToolFactory> = {
 	goal: s => new GoalTool(s),
 };
 
-export type ToolName = keyof typeof BUILTIN_TOOLS;
+export type ToolName = BuiltinToolName;
 
 /**
  * Create tools from BUILTIN_TOOLS registry.