diff --git a/.claude-plugin/plugin.json b/.claude-plugin/plugin.json
index 9b6e8e0..d951eee 100644
--- a/.claude-plugin/plugin.json
+++ b/.claude-plugin/plugin.json
@@ -2,7 +2,7 @@
   "$schema": "https://json.schemastore.org/claude-code-plugin-manifest.json",
   "name": "meridian",
   "description": "Research-first workflows, ruthless code review, orchestrator-led reasoning, and opaque subagent isolation for the entire development lifecycle.",
-  "version": "0.11.1",
+  "version": "0.11.2",
   "author": {
     "name": "KodingDev"
   },
diff --git a/.cursor-plugin/plugin.json b/.cursor-plugin/plugin.json
index ec85ff5..79525df 100644
--- a/.cursor-plugin/plugin.json
+++ b/.cursor-plugin/plugin.json
@@ -2,7 +2,7 @@
   "$schema": "https://json.schemastore.org/claude-code-plugin-manifest.json",
   "name": "meridian",
   "description": "Research-first workflows, ruthless code review, orchestrator-led reasoning, and opaque subagent isolation for the entire development lifecycle.",
-  "version": "0.11.1",
+  "version": "0.11.2",
   "author": {
     "name": "KodingDev"
   },
diff --git a/.plugin/plugin.json b/.plugin/plugin.json
index ed03d74..32ae663 100644
--- a/.plugin/plugin.json
+++ b/.plugin/plugin.json
@@ -1,5 +1,5 @@
 {
   "name": "meridian",
-  "version": "0.11.1",
+  "version": "0.11.2",
   "hooks": "./hooks/hooks-copilot.json"
 }
diff --git a/CHANGELOG.md b/CHANGELOG.md
index ce50261..2607315 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,25 @@ All notable changes to Meridian are recorded here. The format follows
 to [Semantic Versioning](https://semver.org/spec/v2.0.0.html). History before
 0.11.0 lives in the git log.
 
+## [0.11.2] - 2026-07-03
+
+### Added
+
+- Codex host support, alongside the existing Claude Code, Cursor, and Copilot hosts.
+  `detectHost` recognizes Codex by the un-prefixed `PLUGIN_ROOT` it sets — Claude sets only
+  `CLAUDE_PLUGIN_ROOT`, which Codex also sets as a compat alias — and routes Codex session
+  state to `CODEX_HOME` (default `~/.codex`). Codex loads the plugin's default
+  `hooks/hooks.json` and shares Claude's `hookSpecificOutput` contract, so orientation and
+  the periodic routing audit inject on `SessionStart` and `UserPromptSubmit`, and the
+  commit-attribution `PreToolUse` guard applies.
+
+### Fixed
+
+- Copilot's `research` and `triangulate` subagents keep web access: their `tools` arrays add
+  Copilot's `web_fetch` tool, which — unlike `Read`/`Grep`/`Glob`/`Bash`, whose Claude names
+  Copilot resolves as aliases — has no Claude-name alias, so `WebFetch`/`WebSearch` alone
+  resolved to nothing and left those agents with no web tool.
+
 ## [0.11.1] - 2026-06-29
 
 ### Changed
diff --git a/README.md b/README.md
index 3b260ec..1bae748 100644
--- a/README.md
+++ b/README.md
@@ -58,10 +58,14 @@ Hooks are Node scripts (`node ./hooks/*.mjs`) — no Git Bash or shell polyglot
 
 ### GitHub Copilot CLI
 
-Copilot CLI installs the same plugin via its `/plugin` commands and loads the skills and subagents directly. Subagent `tools` are declared as YAML arrays of Claude tool names (`[Read, Grep, Glob, Bash, …]`); Copilot resolves these case-insensitively to its own primitives (`read`, `search`, `execute`, `web`), so the agents get full file/search/shell/web access rather than the bare baseline.
+Copilot CLI installs the same plugin via its `/plugin` commands and loads the skills and subagents directly. Copilot resolves the Claude subagent tool names as compatible aliases — `Read`, `Grep`, `Glob`, `Bash` map to its `view`, `grep`, `glob`, `bash` tools — so file, search, and shell access carry over unchanged. Its web tool (`web_fetch`) has no Claude-name alias, so the agents that need the web (`research`, `triangulate`) also list `web_fetch` explicitly; otherwise `WebFetch`/`WebSearch` resolve to nothing and the agent silently loses web access.
 
 Hooks ship in Copilot's own format: Copilot's command schema treats `command` as a shell string and has no `args` array, so the Claude exec-form config would run a bare `node`. Copilot is pointed at `hooks/hooks-copilot.json` via `.plugin/plugin.json` (a manifest slot Copilot reads but Claude and Cursor don't). Session orientation injects via a flat `additionalContext` on `sessionStart`; prompt submission is state-only, because Copilot's `userPromptSubmitted` hook cannot inject context (same ceiling as Cursor).
 
+### Codex
+
+Codex CLI installs the plugin from the same marketplace and loads the plugin's default `hooks/hooks.json` — the same Claude-shaped hook config (event → matcher groups → `{ "type": "command" }`) — sharing Claude's `hookSpecificOutput` context contract. So, unlike Cursor and Copilot, orientation injects on `SessionStart` **and** the routing audit injects on `UserPromptSubmit`, and the commit-attribution `PreToolUse` guard runs. Codex is detected by the un-prefixed `PLUGIN_ROOT` it sets (Claude sets only `CLAUDE_PLUGIN_ROOT`, which Codex also sets as a compat alias); state lives under `CODEX_HOME` (default `~/.codex`). Codex does not honor a plugin-manifest hook redirect ([openai/codex#16430](https://github.com/openai/codex/issues/16430)), so there is no Codex-specific hooks file — the default `hooks/hooks.json` drives it. Plugin hooks install untrusted; run one interactive Codex session to review and trust them, after which they fire automatically.
+
 Hook tests: `node --test test/meridian-hooks.test.mjs`
 
 ## Credit
diff --git a/agents/research.md b/agents/research.md
index 9fb1997..2576411 100644
--- a/agents/research.md
+++ b/agents/research.md
@@ -1,7 +1,7 @@
 ---
 name: research
 description: Verify external-API/library/protocol facts against live documentation. Returns facts and source URLs, never reasoning chains or hedging. Used by the research skill to isolate doc-fetching from orchestrator context.
-tools: [WebFetch, WebSearch, Read, Grep, Glob]
+tools: [WebFetch, WebSearch, Read, Grep, Glob, web_fetch]
 ---
 
 # Research Agent
diff --git a/agents/triangulate.md b/agents/triangulate.md
index d3f4ccd..f24f8c4 100644
--- a/agents/triangulate.md
+++ b/agents/triangulate.md
@@ -1,7 +1,7 @@
 ---
 name: triangulate
 description: Multi-source verification subagent. Reads candidate sources, returns a Ground Truth Audit with confidence label and a concrete falsifier. Used by the triangulate skill to isolate heavy verification reading from orchestrator context.
-tools: [Read, Grep, Glob, Bash, WebFetch, WebSearch]
+tools: [Read, Grep, Glob, Bash, WebFetch, WebSearch, web_fetch]
 ---
 
 # Triangulate Agent
diff --git a/hooks/lib/host.mjs b/hooks/lib/host.mjs
index e172dff..4f56c82 100644
--- a/hooks/lib/host.mjs
+++ b/hooks/lib/host.mjs
@@ -22,11 +22,14 @@ function resolveStateBase(name) {
   const claude = join(homedir(), ".claude");
   const cursor = join(homedir(), ".cursor");
   const copilot = process.env.COPILOT_HOME || join(homedir(), ".copilot");
-  // Copilot sets CLAUDE_PLUGIN_ROOT too, so its branch must precede that fallback.
+  const codex = process.env.CODEX_HOME || join(homedir(), ".codex");
+  // Copilot and Codex both set CLAUDE_PLUGIN_ROOT (as a compat alias), so their
+  // branches must precede that fallback or they'd resolve to ~/.claude.
   const candidates = [
     () => process.env.CLAUDE_CONFIG_DIR,
     () => name === "cursor" && cursor,
     () => name === "copilot" && copilot,
+    () => name === "codex" && codex,
     () => process.env.CLAUDE_PLUGIN_ROOT && claude,
     () => existsSync(claude) && claude,
     () => existsSync(cursor) && cursor,
@@ -41,9 +44,14 @@ function resolveStateBase(name) {
 /**
  * Detect the host once. Cursor sets `CURSOR_PLUGIN_ROOT` and injects context only
  * on `SessionStart` (via `additional_context`); Copilot sets `COPILOT_PLUGIN_ROOT`
- * and injects on `SessionStart` only (via flat `additionalContext`); Claude injects
- * on every event (via `hookSpecificOutput`). Copilot also sets `CLAUDE_PLUGIN_ROOT`,
- * so it must be checked before the Claude default.
+ * and injects on `SessionStart` only (via flat `additionalContext`); Codex sets the
+ * un-prefixed `PLUGIN_ROOT` and, like Claude, injects on every event via
+ * `hookSpecificOutput`; Claude injects on every event via `hookSpecificOutput`.
+ * Copilot and Codex also set `CLAUDE_PLUGIN_ROOT` (compat), so both must be checked
+ * before the Claude default. Codex ships no unique identity var, so the un-prefixed
+ * `PLUGIN_ROOT` — which Codex sets but Claude does not — is the documented
+ * discriminator; a misdetect only picks the wrong state dir, since Codex and Claude
+ * share the `hookSpecificOutput` emit shape.
  * @returns {Host}
  */
 export function detectHost() {
@@ -52,7 +60,9 @@ export function detectHost() {
     ? "cursor"
     : process.env.COPILOT_PLUGIN_ROOT
       ? "copilot"
-      : "claude";
+      : process.env.PLUGIN_ROOT
+        ? "codex"
+        : "claude";
   return {
     name,
     stateBase: resolveStateBase(name),
diff --git a/hooks/lib/types.mjs b/hooks/lib/types.mjs
index 92be2f4..d2085ca 100644
--- a/hooks/lib/types.mjs
+++ b/hooks/lib/types.mjs
@@ -14,7 +14,7 @@
  * @property {string} [hook_event_name]
  */
 
-/** @typedef {"claude" | "cursor" | "copilot"} HostName */
+/** @typedef {"claude" | "cursor" | "copilot" | "codex"} HostName */
 
 /** The hook events that can inject context. @typedef {"SessionStart" | "UserPromptSubmit"} HookEvent */
 
diff --git a/test/meridian-hooks.test.mjs b/test/meridian-hooks.test.mjs
index 85aded7..98694ff 100644
--- a/test/meridian-hooks.test.mjs
+++ b/test/meridian-hooks.test.mjs
@@ -96,6 +96,23 @@ test("hooks.json SessionStart matcher stays empty so it catches the compact sour
   }
 });
 
+test("session-start emits orientation under Codex (un-prefixed PLUGIN_ROOT)", () => {
+  // Codex is detected via PLUGIN_ROOT and, like Claude, takes the hookSpecificOutput
+  // emit path — so the same orientation payload must come back. CODEX_HOME points state
+  // at the temp dir so the real ~/.codex is untouched.
+  const cfg = tmpConfig();
+  const { code, stdout } = runHook(
+    "session-start.mjs",
+    { session_id: SID, hook_event_name: "SessionStart", source: "startup" },
+    { PLUGIN_ROOT: "/fake/plugin", CLAUDE_PLUGIN_ROOT: "/fake/plugin", CODEX_HOME: cfg },
+  );
+  assert.equal(code, 0);
+  const out = JSON.parse(stdout);
+  assert.equal(out.hookSpecificOutput.hookEventName, "SessionStart");
+  assert.match(out.hookSpecificOutput.additionalContext, /\[Meridian orientation\]/);
+  rmSync(cfg, { recursive: true, force: true });
+});
+
 test("pre-tool-use denies a git commit carrying AI attribution", () => {
   for (const command of [
     'git commit -m "feat: x\n\nCo-Authored-By: Claude <noreply@anthropic.com>"',
diff --git a/test/meridian-lib.test.mjs b/test/meridian-lib.test.mjs
index 5058bdc..ce40ed8 100644
--- a/test/meridian-lib.test.mjs
+++ b/test/meridian-lib.test.mjs
@@ -132,13 +132,44 @@ test("Copilot state base stays ~/.copilot even when CLAUDE_PLUGIN_ROOT is also s
   }
 });
 
+test("detectHost resolves the Codex state base and injects on every event", () => {
+  // Codex ships no unique identity var; it sets the un-prefixed PLUGIN_ROOT (plus
+  // CLAUDE_PLUGIN_ROOT for compat) — the documented discriminator from Claude, which
+  // sets only CLAUDE_PLUGIN_ROOT. Like Claude, Codex injects on every event.
+  const saved = {
+    CURSOR_PLUGIN_ROOT: process.env.CURSOR_PLUGIN_ROOT,
+    COPILOT_PLUGIN_ROOT: process.env.COPILOT_PLUGIN_ROOT,
+    PLUGIN_ROOT: process.env.PLUGIN_ROOT,
+    CODEX_HOME: process.env.CODEX_HOME,
+    CLAUDE_CONFIG_DIR: process.env.CLAUDE_CONFIG_DIR,
+    CLAUDE_PLUGIN_ROOT: process.env.CLAUDE_PLUGIN_ROOT,
+  };
+  delete process.env.CLAUDE_CONFIG_DIR;
+  delete process.env.CURSOR_PLUGIN_ROOT;
+  delete process.env.COPILOT_PLUGIN_ROOT;
+  delete process.env.CODEX_HOME;
+  process.env.PLUGIN_ROOT = "/fake/plugin";
+  process.env.CLAUDE_PLUGIN_ROOT = "/fake/plugin";
+  const host = detectHost();
+  assert.equal(host.name, "codex");
+  assert.equal(host.stateBase, join(homedir(), ".codex"));
+  assert.equal(host.supportsContext("SessionStart"), true);
+  assert.equal(host.supportsContext("UserPromptSubmit"), true);
+  for (const [key, val] of Object.entries(saved)) {
+    if (val === undefined) delete process.env[key];
+    else process.env[key] = val;
+  }
+});
+
 test("detectHost defaults to claude and injects on every event", () => {
   const saved = {
     CURSOR_PLUGIN_ROOT: process.env.CURSOR_PLUGIN_ROOT,
     COPILOT_PLUGIN_ROOT: process.env.COPILOT_PLUGIN_ROOT,
+    PLUGIN_ROOT: process.env.PLUGIN_ROOT,
   };
   delete process.env.CURSOR_PLUGIN_ROOT;
   delete process.env.COPILOT_PLUGIN_ROOT;
+  delete process.env.PLUGIN_ROOT;
   const host = detectHost();
   assert.equal(host.name, "claude");
   assert.equal(host.supportsContext("UserPromptSubmit"), true);