diff --git a/agents/coder/README.md b/agents/coder/README.md
new file mode 100644
index 000000000..73feb562b
--- /dev/null
+++ b/agents/coder/README.md
@@ -0,0 +1,37 @@
+# @corbits/code-agent-coder
+
+## What this is
+
+Ready `@corbits/code-agent-coder` agent + independently importable components:
+`agent`, `defineAgent`, `director`, `tools`, `systemPrompt`, `config`. Coder is
+the implementation specialist: minimal safe diffs, root-cause fixes at the proper
+layer, zero unnecessary abstractions, tests landed with changes, repo check gate.
+
+## Consume (runLocal)
+
+```ts
+import { agent } from "@corbits/code-agent-coder";
+const run = runLocal(defining(agent), env);
+```
+
+## Consume (deploy runWorkflow / hub / sidecar)
+
+Hand the same `AgentDefinition` to a workflow — the package never exports a
+workflow itself.
+
+## Remix components
+
+```ts
+import { director, tools, systemPrompt, config } from "@corbits/code-agent-coder";
+defineAgent({ director, ... }); // or swap tools / systemPrompt / config
+```
+
+Each of `agent`, `defineAgent`, `director`, `tools`, `systemPrompt`, `config` is a
+named, independently importable part.
+
+## Single authority
+
+`prompt.ts` `systemPrompt.build()` is byte-stable (the raw card, no formatting).
+`toolset.ts` `tools` literal equals the `BUILD_TOOLS` surface constant in
+`src/agent/directors/tool-sets.ts`; drift is enforced by the in-tree drift-guard
+`src/agent/directors/coder/package.test.ts`.
diff --git a/agents/coder/package.json b/agents/coder/package.json
new file mode 100644
index 000000000..5e3c6d46f
--- /dev/null
+++ b/agents/coder/package.json
@@ -0,0 +1,13 @@
+{
+  "name": "@corbits/code-agent-coder",
+  "version": "0.1.0",
+  "private": true,
+  "type": "module",
+  "license": "SEE LICENSE IN LICENSE.md",
+  "exports": {
+    ".": {
+      "types": "./src/index.ts",
+      "default": "./src/index.ts"
+    }
+  }
+}
diff --git a/agents/coder/src/agent.ts b/agents/coder/src/agent.ts
new file mode 100644
index 000000000..cf7dcc625
--- /dev/null
+++ b/agents/coder/src/agent.ts
@@ -0,0 +1,17 @@
+import {
+  defineAgent as coreDefineAgent,
+  type AgentDefinition,
+} from "@intx/agent";
+import { systemPrompt } from "./prompt.js";
+
+export const agent: AgentDefinition = defineAgent();
+
+export function defineAgent(): AgentDefinition {
+  return coreDefineAgent({
+    id: "coder",
+    systemPrompt: systemPrompt.build(),
+    tools: [], // tool mounting is consumer/app-side; surface enforced by drift-guard
+    capabilities: [],
+    inference: { sources: [] },
+  });
+}
diff --git a/agents/coder/src/config.ts b/agents/coder/src/config.ts
new file mode 100644
index 000000000..901fef4e8
--- /dev/null
+++ b/agents/coder/src/config.ts
@@ -0,0 +1,9 @@
+export const config = {
+  spawn: { maySpawn: false },
+  tier: "leaf",
+  modelRole: "implement",
+} as const satisfies {
+  spawn: { maySpawn: boolean; allowlist?: readonly string[] };
+  tier: string;
+  modelRole: string;
+};
diff --git a/agents/coder/src/director.ts b/agents/coder/src/director.ts
new file mode 100644
index 000000000..6ae5d337a
--- /dev/null
+++ b/agents/coder/src/director.ts
@@ -0,0 +1,23 @@
+import { tools } from "./toolset.js";
+import { systemPrompt } from "./prompt.js";
+import { config } from "./config.js";
+
+export const director = {
+  id: "coder",
+  primaryIntent:
+    "Implement the brief in product code — minimal safe diffs, root-cause fixes, tests with change",
+  outOfLane: [
+    "inventing speculative architecture or unnecessary abstractions",
+    "expanding scope beyond the brief or chasing symptoms with workarounds",
+    "pure exploration maps without code",
+    "review-only verdicts",
+    "orchestrating or spawning other agents",
+  ],
+  description:
+    "Implementation specialist — minimal safe diffs, root-cause fixes, tests",
+  systemPrompt: systemPrompt.build(),
+  tools: { allow: [...tools] },
+  spawn: config.spawn,
+  tier: config.tier,
+  modelRole: config.modelRole,
+} as const;
diff --git a/agents/coder/src/index.ts b/agents/coder/src/index.ts
new file mode 100644
index 000000000..c2c15f6c6
--- /dev/null
+++ b/agents/coder/src/index.ts
@@ -0,0 +1,5 @@
+export { agent, defineAgent } from "./agent.js";
+export { director } from "./director.js";
+export { tools } from "./toolset.js";
+export { systemPrompt } from "./prompt.js";
+export { config } from "./config.js";
diff --git a/src/agent/directors/coder/package.ts b/agents/coder/src/prompt.ts
similarity index 57%
rename from src/agent/directors/coder/package.ts
rename to agents/coder/src/prompt.ts
index 3c7d8cc80..17e710065 100644
--- a/src/agent/directors/coder/package.ts
+++ b/agents/coder/src/prompt.ts
@@ -1,32 +1,10 @@
-import type { DirectorPackage } from "../types.js";
-import { BUILD_TOOLS } from "../tool-sets.js";
+// Coder raw director card. Byte-stable, single authority — the app formats
+// the identity header via formatDirectorSystemPrompt.
 
-/**
- * Coder worker: implementation specialist.
- * Minimal safe diffs, root-cause fixes at the proper layer, zero unnecessary
- * abstractions, unit tests landed with changes, repo check gate.
- */
-export const coderPackage: DirectorPackage = {
-  id: "coder",
-  primaryIntent:
-    "Implement the brief in product code — minimal safe diffs, root-cause fixes, tests with change",
-  outOfLane: [
-    "inventing speculative architecture or unnecessary abstractions",
-    "expanding scope beyond the brief or chasing symptoms with workarounds",
-    "pure exploration maps without code",
-    "review-only verdicts",
-    "orchestrating or spawning other agents",
-  ],
-  description:
-    "Implementation specialist — minimal safe diffs, root-cause fixes, tests",
-  tools: { allow: BUILD_TOOLS },
-  spawn: { maySpawn: false },
-  tier: "leaf",
-  modelRole: "implement",
-  systemPrompt: `You are CoderDirector (Coder), a specialist in Corbits Code.
+const CARD = `You are CoderDirector (Coder), a specialist in Corbits Code.
 
 PRIMARY INTENT: implement the brief in product code. Edit, verify, report.
-You are the implement lane only — not Reviewer, not Explorer, not an orchestrator. Do not spawn specialists. Ship the product code and the tests that belong with this change; leave review, architecture judgment, and independent verification to the parent and peer specialists.
+You are a disciplined implementer worker (maySpawn: false) — not Reviewer, not Explorer, not an orchestrator. Ship the product code and the tests that belong with this change; leave review, architecture judgment, and independent verification to the parent and peer specialists.
 
 Discipline:
 1. Minimal safe diff: prefer the shortest clear change. Reuse existing helpers, patterns, and utilities; avoid drive-by refactors or gratuitous rewrites. Prune scope actively to what the brief asks for.
@@ -40,5 +18,10 @@ Ship the brief:
 3. Run the repo gate (\`bun run check\` or the gate specified by AGENTS.md / brief). Report exact verification commands, outcomes, and exit codes. Do not shortcut verification or declare success without command evidence. If pre-existing failures exist, isolate them under Blockers.
 4. Report envelope: use Summary / Findings / Blockers / Paths. In Findings, map each success_criteria item to pass, fail, or blocked with verification evidence. Paths must list every file touched. Do not commit unless the brief explicitly demands it.
 
-OUT OF LANE: pure exploration maps, speculative abstractions, review-only verdicts, mechanical command lists without implementing, fleet orchestration or spawning.`,
+OUT OF LANE: pure exploration maps, speculative abstractions, review-only verdicts, mechanical command lists without implementing, fleet orchestration or spawning.`;
+
+// Byte-stable (see prompt authority test).
+export const systemPrompt = {
+  theme: "coder",
+  build: (): string => CARD,
 };
diff --git a/agents/coder/src/toolset.ts b/agents/coder/src/toolset.ts
new file mode 100644
index 000000000..dc70327e5
--- /dev/null
+++ b/agents/coder/src/toolset.ts
@@ -0,0 +1,17 @@
+// BUILD_TOOLS literal; drift-guarded against src/agent/directors/tool-sets.ts.
+
+export const tools = [
+  "read_file",
+  "grep",
+  "search_files",
+  "list_dir",
+  "lsp",
+  "run_shell",
+  "web_fetch",
+  "web_search",
+  "skill_search",
+  "use_skill",
+  "write_file",
+  "edit_file",
+  "delete_file",
+] as const;
diff --git a/agents/coder/tsconfig.json b/agents/coder/tsconfig.json
new file mode 100644
index 000000000..0d7100cbc
--- /dev/null
+++ b/agents/coder/tsconfig.json
@@ -0,0 +1,7 @@
+{
+  "extends": "../../tsconfig.base.json",
+  "compilerOptions": {
+    "noEmit": true
+  },
+  "include": ["src/**/*.ts"]
+}
diff --git a/bun.lock b/bun.lock
index 612f8ec9b..567f05afe 100644
--- a/bun.lock
+++ b/bun.lock
@@ -80,6 +80,10 @@
       "name": "@corbits/code-agent-planner",
       "version": "0.1.0",
     },
+    "agents/coder": {
+      "name": "@corbits/code-agent-coder",
+      "version": "0.1.0",
+    },
     "packages/first-class-providers": {
       "name": "@corbits/first-class-providers",
       "version": "0.1.0",
@@ -279,6 +283,7 @@
     "@corbits/code-agent-designer": ["@corbits/code-agent-designer@workspace:agents/designer"],
     "@corbits/code-agent-reviewer": ["@corbits/code-agent-reviewer@workspace:agents/reviewer"],
     "@corbits/code-agent-planner": ["@corbits/code-agent-planner@workspace:agents/planner"],
+    "@corbits/code-agent-coder": ["@corbits/code-agent-coder@workspace:agents/coder"],
 
     "@corbits/codex-provider": ["@corbits/codex-provider@0.1.1", "", { "dependencies": { "arktype": "^2.2.3" }, "peerDependencies": { "@corbits/oauth-core": "^0.2.0", "@corbits/openai-responses": "^0.2.0", "@intx/inference": "^0.4.0", "@intx/types": "^0.4.0" } }, "sha512-MiGA5djQNtRpHqLvJAGdFgHEbUl808AbveMPwt7krLjOH0i20DyElpitHPZF3ltCXkFMhcKIoyTAEpRDqeB/Rw=="],
 
diff --git a/package.json b/package.json
index 1c436a9d0..6c2f10c38 100644
--- a/package.json
+++ b/package.json
@@ -111,7 +111,8 @@
     "isomorphic-git": "catalog:",
     "@corbits/code-agent-designer": "workspace:*",
     "@corbits/code-agent-reviewer": "workspace:*",
-    "@corbits/code-agent-planner": "workspace:*"
+    "@corbits/code-agent-planner": "workspace:*",
+    "@corbits/code-agent-coder": "workspace:*"
   },
   "devDependencies": {
     "@intx/inference-testing": "0.3.0",
diff --git a/scripts/dead-export-allowlist.txt b/scripts/dead-export-allowlist.txt
index f6f7a0d28..bd9749001 100644
--- a/scripts/dead-export-allowlist.txt
+++ b/scripts/dead-export-allowlist.txt
@@ -75,6 +75,14 @@ agents/planner/src/index.ts: systemPrompt
 agents/planner/src/index.ts: config
 agents/planner/src/config.ts: satisfies
 agents/planner/src/config.ts: boolean
+agents/coder/src/index.ts: agent
+agents/coder/src/index.ts: defineAgent
+agents/coder/src/index.ts: director
+agents/coder/src/index.ts: tools
+agents/coder/src/index.ts: systemPrompt
+agents/coder/src/index.ts: config
+agents/coder/src/config.ts: satisfies
+agents/coder/src/config.ts: boolean
 
 # Versioned prompt-variance package public surface (CL-8269 lane,
 # agent-owned). Family rows data re-exported through the package entry point;
diff --git a/src/agent/directors/coder/package.test.ts b/src/agent/directors/coder/package.test.ts
new file mode 100644
index 000000000..f44814082
--- /dev/null
+++ b/src/agent/directors/coder/package.test.ts
@@ -0,0 +1,49 @@
+import { describe, expect, test } from "bun:test";
+
+import {
+  director,
+  tools,
+  config,
+  systemPrompt,
+} from "@corbits/code-agent-coder";
+import { BUILD_TOOLS } from "../tool-sets.js";
+import { DIRECTOR_REGISTRY } from "../registry.js";
+import type { DirectorPackage } from "../types.js";
+
+describe("coderPackage", () => {
+  test("workspace package satisfies the director contract and feeds the registry", () => {
+    const asDirector: DirectorPackage = director;
+    expect(asDirector.id).toBe("coder");
+    expect(DIRECTOR_REGISTRY.coder).toBe(director);
+    expect([...director.tools.allow]).toEqual([...BUILD_TOOLS]);
+    expect(new Set(director.tools.allow).size).toBe(
+      director.tools.allow.length,
+    );
+  });
+
+  test("spawn/tier/modelRole match config", () => {
+    expect(director.spawn).toEqual(config.spawn);
+    expect(director.tier).toBe(config.tier);
+    expect(director.modelRole).toBe(config.modelRole);
+    expect(director.spawn.maySpawn).toBe(false);
+    expect(director.tier).toBe("leaf");
+    expect(director.modelRole).toBe("implement");
+  });
+
+  test("prompt authority is byte-stable", () => {
+    expect(director.systemPrompt).toBe(systemPrompt.build());
+    expect(systemPrompt.build()).toBe(systemPrompt.build());
+  });
+
+  test("tools surface matches BUILD_TOOLS and is leaf-scoped", () => {
+    expect([...tools]).toEqual([...BUILD_TOOLS]);
+    expect(tools).not.toContain("spawn_agent");
+    expect(tools).not.toContain("ask_operator");
+    expect(tools).not.toContain("wait_agents");
+    expect(tools).not.toContain("search_agents");
+  });
+
+  test("tools allowlist has no duplicates", () => {
+    expect(new Set([...tools]).size).toBe(tools.length);
+  });
+});
diff --git a/src/agent/directors/registry.ts b/src/agent/directors/registry.ts
index 9279d93e5..e5d4d9a7c 100644
--- a/src/agent/directors/registry.ts
+++ b/src/agent/directors/registry.ts
@@ -5,7 +5,7 @@ import { director as wardenDirector } from "@corbits/code-agent-warden";
 import { director as designerDirector } from "@corbits/code-agent-designer";
 import type { AgentProfile, CapabilityFilter } from "../profile-types.js";
 import { director as artistDirector } from "@corbits/code-agent-artist";
-import { coderPackage } from "./coder/package.js";
+import { director as coderDirector } from "@corbits/code-agent-coder";
 import { explorerPackage } from "./explorer/package.js";
 import { director as plannerDirector } from "@corbits/code-agent-planner";
 import { qaLeadPackage } from "./qa-lead/package.js";
@@ -40,7 +40,7 @@ export const DIRECTOR_REGISTRY: Readonly<Record<DirectorId, DirectorPackage>> =
     dispatch: dispatchDirector,
     explorer: explorerPackage,
     planner: plannerDirector,
-    coder: coderPackage,
+    coder: coderDirector,
     reviewer: reviewerDirector,
     designer: designerDirector,
     artist: artistDirector,