diff --git a/src/__tests__/local-agent-path-resolution.test.ts b/src/__tests__/local-agent-path-resolution.test.ts
new file mode 100644
index 0000000..74b34cb
--- /dev/null
+++ b/src/__tests__/local-agent-path-resolution.test.ts
@@ -0,0 +1,213 @@
+/**
+ * REGRESSION (issue #78 — macOS/POSIX): the local-agent detector resolved the CLI binary
+ * against the SERVER process PATH. When T3MP3ST is launched from Finder, the desktop app, or
+ * any non-interactive shell, launchd hands it a minimal PATH (/usr/bin:/bin:/usr/sbin:/sbin) —
+ * missing ~/.local/bin (Claude Code's native install), Homebrew, npm-global, and version-manager
+ * shims (mise/nvm/fnm). `execFile('claude', …)` then throws ENOENT and an installed, working CLI
+ * is reported `installed:false` (the Settings checkboxes go dead — reads like a UI bug).
+ *
+ * The fix is `resolveBin()`: pure-fs resolution over PATH + a curated set of well-known install
+ * dirs under the real agent home, with an executable-file check, fail-open to the bare name.
+ * These tests pin the resolver in isolation, the detector wiring, AND the two spawn call-sites
+ * (runLocalAgent / localAgentChat) the fix rewired — all through the public API.
+ *
+ * POSIX-only by design: `resolveBin` short-circuits on win32 (Windows resolution — where.exe /
+ * .cmd shims — is PR #18's domain, deliberately not duplicated here). The win32 case is asserted
+ * via a platform stub so the boundary is documented and locked.
+ */
+import { describe, it, expect, afterEach } from 'vitest';
+import { mkdtempSync, mkdirSync, writeFileSync, symlinkSync, rmSync } from 'fs';
+import { tmpdir } from 'os';
+import { join } from 'path';
+import { resolveBin, detectLocalAgents, runLocalAgent, localAgentChat } from '../agent/local-agents.js';
+
+const FAKE_CLI = '#!/bin/sh\necho "1.2.3"\n';
+// For the chat path, which writes the prompt to the child's stdin: drain it before replying so the
+// parent's write()/end() completes cleanly (no EPIPE races), then emit a clean, non-error reply.
+const FAKE_CLI_STDIN = '#!/bin/sh\ncat >/dev/null 2>&1\necho "1.2.3"\n';
+const tmpDirs: string[] = [];
+const savedEnv = { PATH: process.env.PATH, AGENT_HOME: process.env.T3MP3ST_AGENT_HOME };
+
+/** A throwaway dir; tracked for afterEach cleanup. */
+function scratch(): string {
+  const d = mkdtempSync(join(tmpdir(), 't3mp3st-pathres-'));
+  tmpDirs.push(d);
+  return d;
+}
+
+/** Drop an executable (0o755) fake binary at `dir/name`; returns its absolute path. */
+function putExe(dir: string, name: string, content: string = FAKE_CLI): string {
+  mkdirSync(dir, { recursive: true });
+  const p = join(dir, name);
+  writeFileSync(p, content, { mode: 0o755 });
+  return p;
+}
+
+afterEach(() => {
+  process.env.PATH = savedEnv.PATH;
+  if (savedEnv.AGENT_HOME === undefined) delete process.env.T3MP3ST_AGENT_HOME; else process.env.T3MP3ST_AGENT_HOME = savedEnv.AGENT_HOME;
+  for (const d of tmpDirs.splice(0)) { try { rmSync(d, { recursive: true, force: true }); } catch { /* noop */ } }
+});
+
+describe('resolveBin — macOS/POSIX well-known-dir resolution (issue #78)', () => {
+  it('finds a CLI in ~/.local/bin even when PATH omits it (the reported bug)', () => {
+    const home = scratch();
+    const bin = putExe(join(home, '.local', 'bin'), 'faketool');
+    process.env.T3MP3ST_AGENT_HOME = home;      // real agent home for this scan
+    process.env.PATH = '/usr/bin:/bin';         // minimal launchd-style PATH — omits ~/.local/bin
+
+    expect(resolveBin('faketool')).toBe(bin);
+  });
+
+  // A representative spread of the curated dirs (not just index-0 ~/.local/bin) so a typo or
+  // reorder in any entry is caught. Paths are relative to the agent home.
+  it.each([
+    ['.asdf/shims'],
+    ['.bun/bin'],
+    ['.local/share/pnpm'],
+  ])('resolves a CLI installed under the well-known dir %s', (rel) => {
+    const home = scratch();
+    const bin = putExe(join(home, ...rel.split('/')), 'faketool');
+    process.env.T3MP3ST_AGENT_HOME = home;
+    process.env.PATH = '/usr/bin:/bin';
+    expect(resolveBin('faketool')).toBe(bin);
+  });
+
+  it('finds a CLI under an nvm per-version bin dir (dynamic enumeration)', () => {
+    const home = scratch();
+    const bin = putExe(join(home, '.nvm', 'versions', 'node', 'v20.11.0', 'bin'), 'faketool');
+    process.env.T3MP3ST_AGENT_HOME = home;
+    process.env.PATH = '/usr/bin:/bin';
+    expect(resolveBin('faketool')).toBe(bin);
+  });
+
+  it('finds a CLI under an fnm per-version bin dir (dynamic enumeration)', () => {
+    const home = scratch();
+    const bin = putExe(join(home, '.local', 'share', 'fnm', 'node-versions', 'v20.11.0', 'installation', 'bin'), 'faketool');
+    process.env.T3MP3ST_AGENT_HOME = home;
+    process.env.PATH = '/usr/bin:/bin';
+    expect(resolveBin('faketool')).toBe(bin);
+  });
+
+  it('resolves via PATH when the CLI is on it (rich-shell launch still works)', () => {
+    const dir = scratch();
+    const bin = putExe(dir, 'faketool');
+    process.env.T3MP3ST_AGENT_HOME = scratch(); // empty home — force the hit to come from PATH
+    process.env.PATH = `/usr/bin:${dir}`;
+
+    expect(resolveBin('faketool')).toBe(bin);
+  });
+
+  it('prefers a PATH match over a well-known-dir match when both exist (shell precedence)', () => {
+    const home = scratch();
+    const wellKnown = putExe(join(home, '.local', 'bin'), 'faketool');
+    const pathDir = scratch();
+    const onPath = putExe(pathDir, 'faketool');
+    process.env.T3MP3ST_AGENT_HOME = home;
+    process.env.PATH = `/usr/bin:${pathDir}`;    // PATH scanned before well-known dirs
+
+    expect(resolveBin('faketool')).toBe(onPath);
+    expect(resolveBin('faketool')).not.toBe(wellKnown);
+  });
+
+  it('follows a symlink to an executable (asdf/nvm shims & Claude Code\'s own install are symlinks)', () => {
+    const home = scratch();
+    const real = putExe(join(home, 'tools'), 'realtool');
+    const linkDir = join(home, '.local', 'bin');
+    mkdirSync(linkDir, { recursive: true });
+    const link = join(linkDir, 'faketool');
+    symlinkSync(real, link);
+    process.env.T3MP3ST_AGENT_HOME = home;
+    process.env.PATH = '/usr/bin:/bin';
+
+    expect(resolveBin('faketool')).toBe(link);   // the resolved candidate path, symlink followed for the file-check
+  });
+
+  it('skips a non-executable match (parity with execFile X_OK) and fails open to the bare name', () => {
+    const home = scratch();
+    const p = join(home, '.local', 'bin', 'faketool');
+    mkdirSync(join(home, '.local', 'bin'), { recursive: true });
+    writeFileSync(p, 'not executable', { mode: 0o644 });  // present but not +x
+    process.env.T3MP3ST_AGENT_HOME = home;
+    process.env.PATH = '/usr/bin:/bin';
+
+    expect(resolveBin('faketool')).toBe('faketool');       // not the non-exec path
+  });
+
+  it('does NOT match a directory named like the CLI (dirs carry the search bit; execvp would skip it)', () => {
+    // Regression guard: a bare `accessSync(X_OK)` passes for a directory, so resolveBin would return
+    // the dir → execFile fails EACCES (not ENOENT) → a false installed:true. Require a regular file.
+    const home = scratch();
+    mkdirSync(join(home, '.local', 'bin', 'faketool'), { recursive: true });  // a DIRECTORY, not a binary
+    process.env.T3MP3ST_AGENT_HOME = home;
+    process.env.PATH = '/usr/bin:/bin';
+    expect(resolveBin('faketool')).toBe('faketool');                          // bare name, not the dir path
+  });
+
+  it('returns an already-qualified path unchanged (the bin.includes("/") guard — no re-resolution)', () => {
+    expect(resolveBin('/opt/custom/claude')).toBe('/opt/custom/claude');
+    expect(resolveBin('./rel/claude')).toBe('./rel/claude');
+  });
+
+  it('fails open to the bare name when nothing matches anywhere', () => {
+    process.env.T3MP3ST_AGENT_HOME = scratch();
+    process.env.PATH = '/usr/bin:/bin';
+    expect(resolveBin('definitely-not-a-real-cli-xyz')).toBe('definitely-not-a-real-cli-xyz');
+  });
+
+  it('does NOT scan on win32 — returns the bare name (Windows resolution is PR #18\'s domain)', () => {
+    const home = scratch();
+    putExe(join(home, '.local', 'bin'), 'faketool');
+    process.env.T3MP3ST_AGENT_HOME = home;
+    process.env.PATH = '/usr/bin:/bin';
+    const orig = Object.getOwnPropertyDescriptor(process, 'platform') || { value: process.platform, configurable: true };
+    Object.defineProperty(process, 'platform', { value: 'win32', configurable: true });
+    try {
+      expect(resolveBin('faketool')).toBe('faketool');
+    } finally {
+      Object.defineProperty(process, 'platform', orig);
+    }
+  });
+});
+
+describe('detectLocalAgents — wiring: a well-known-dir CLI is reported installed (issue #78)', () => {
+  it('reports Claude Code installed + versioned when `claude` lives in ~/.local/bin and PATH omits it', async () => {
+    const home = scratch();
+    const claudePath = putExe(join(home, '.local', 'bin'), 'claude');
+    process.env.T3MP3ST_AGENT_HOME = home;
+    process.env.PATH = '/usr/bin:/bin';         // pre-fix: execFile('claude') → ENOENT → installed:false
+    delete process.env.T3MP3ST_DISABLE_LOCAL_AGENTS;  // insurance: a leaked disable flag would short-circuit to []
+
+    const agents = await detectLocalAgents();
+    const claude = agents.find((a) => a.id === 'claude');
+    expect(claude?.installed).toBe(true);
+    expect(claude?.path).toBe(claudePath);
+    expect(claude?.version).toBe('1.2.3');       // parsed from the resolved binary's --version output
+    // codex/hermes are absent from this temp home → still not installed (no false positives).
+    expect(agents.find((a) => a.id === 'codex')?.installed).toBe(false);
+  });
+});
+
+describe('spawn call-sites use the resolved path (issue #78 — detected-but-unspawnable would be worse)', () => {
+  // Behavioral, not a spawn spy: if the rewiring regressed to the bare `spec.bin`, spawn('claude')
+  // under PATH=/usr/bin:/bin throws ENOENT → ok:false / reject. Success proves the resolved path ran.
+  it('runLocalAgent launches the well-known-dir CLI (not the bare name)', async () => {
+    const home = scratch();
+    putExe(join(home, '.local', 'bin'), 'claude');
+    process.env.T3MP3ST_AGENT_HOME = home;
+    process.env.PATH = '/usr/bin:/bin';
+
+    const res = await runLocalAgent('claude', 'ping', { timeoutMs: 4000 });
+    expect(res.ok).toBe(true);
+    expect(res.output).toContain('1.2.3');
+  });
+
+  it('localAgentChat launches the well-known-dir CLI (not the bare name)', async () => {
+    const home = scratch();
+    putExe(join(home, '.local', 'bin'), 'claude', FAKE_CLI_STDIN);
+    process.env.T3MP3ST_AGENT_HOME = home;
+    process.env.PATH = '/usr/bin:/bin';
+
+    await expect(localAgentChat('claude', 'ping', { timeoutMs: 4000 })).resolves.toContain('1.2.3');
+  });
+});
diff --git a/src/agent/local-agents.ts b/src/agent/local-agents.ts
index fed5c4c..cf6b5ed 100644
--- a/src/agent/local-agents.ts
+++ b/src/agent/local-agents.ts
@@ -13,7 +13,7 @@
 // =============================================================================
 
 import { execFile, execFileSync, spawn } from 'child_process';
-import { existsSync, mkdtempSync, readFileSync, rmSync } from 'fs';
+import { accessSync, constants, existsSync, mkdtempSync, readdirSync, readFileSync, rmSync, statSync } from 'fs';
 import { homedir, tmpdir, userInfo } from 'os';
 import { join } from 'path';
 
@@ -182,12 +182,70 @@ export interface AgentDetection {
   ready: boolean;      // installed && authed
 }
 
-function resolvePath(bin: string): string | undefined {
-  try {
-    return execFileSync('command', ['-v', bin], { shell: '/bin/bash', encoding: 'utf8' }).trim() || undefined;
-  } catch {
-    try { return execFileSync('which', [bin], { encoding: 'utf8' }).trim() || undefined; } catch { return undefined; }
+/**
+ * Curated POSIX install dirs an agent CLI commonly lands in, under the REAL agent home (issue #78).
+ *
+ * The bug: a T3MP3ST server launched from Finder / the desktop app / any non-interactive shell
+ * inherits launchd's minimal PATH (/usr/bin:/bin:/usr/sbin:/sbin). That omits every place a CLI
+ * actually installs — so `execFile('claude', …)` throws ENOENT and a working, authed CLI reads as
+ * `installed:false`. We recover it by ALSO scanning these dirs (they are where Claude Code's native
+ * installer, Homebrew, npm-global, and the version managers put their bins). Anchored to agentHome()
+ * — NOT os.homedir() — so a HOME redirect can't hide them (same rationale as `agentHome`).
+ */
+function wellKnownBinDirs(home: string): string[] {
+  const dirs = [
+    join(home, '.local', 'bin'),                       // Claude Code native installer, pipx, mise
+    join(home, '.local', 'share', 'mise', 'shims'),    // mise
+    join(home, '.asdf', 'shims'),                      // asdf
+    '/opt/homebrew/bin',                               // Homebrew (Apple Silicon)
+    '/usr/local/bin',                                  // Homebrew (Intel) / manual installs
+    join(home, '.bun', 'bin'),                         // bun
+    join(home, '.deno', 'bin'),                        // deno
+    join(home, '.volta', 'bin'),                       // volta
+    join(home, '.npm-global', 'bin'),                  // npm prefix override
+    join(home, '.yarn', 'bin'),                        // yarn global
+    join(home, 'Library', 'pnpm'),                     // pnpm (macOS default)
+    join(home, '.local', 'share', 'pnpm'),             // pnpm (XDG)
+    '/opt/local/bin',                                  // MacPorts
+  ];
+  // Version managers keep a per-version bin dir — enumerate the installed versions so an
+  // npm-global CLI (e.g. codex) under the active node still resolves under a minimal PATH.
+  for (const nodeVersions of [join(home, '.nvm', 'versions', 'node')]) {
+    try { for (const v of readdirSync(nodeVersions)) dirs.push(join(nodeVersions, v, 'bin')); } catch { /* not present */ }
   }
+  for (const fnmDir of [join(home, '.local', 'share', 'fnm', 'node-versions'),
+                        join(home, 'Library', 'Application Support', 'fnm', 'node-versions')]) {
+    try { for (const v of readdirSync(fnmDir)) dirs.push(join(fnmDir, v, 'installation', 'bin')); } catch { /* not present */ }
+  }
+  return dirs;
+}
+
+/**
+ * Absolute path to `bin`, resolved WITHOUT a shell against PATH plus the well-known install dirs
+ * (issue #78). Fail-open: an unresolved name is returned unchanged so `execFile`/`spawn` still throw
+ * the same ENOENT (→ `installed:false`) they did before — no behavior change when a CLI is truly
+ * absent. Pure-fs (no shell) so it can't hang or be injected, and it uses an X_OK access check to
+ * match `execFile`'s own executable-file semantics (a non-executable name-collision is skipped, not
+ * returned). win32 is intentionally NOT handled here (where.exe / .cmd-shim resolution is PR #18's
+ * domain) — the bare name is returned so Node's own %PATH%/PATHEXT lookup stays in effect.
+ */
+export function resolveBin(bin: string): string {
+  if (process.platform === 'win32' || bin.includes('/')) return bin;
+  const path = process.env.PATH || '';
+  for (const dir of [...path.split(':'), ...wellKnownBinDirs(agentHome())]) {
+    // Absolute dirs only: skips blank PATH segments (whose POSIX "= cwd" meaning is a known
+    // CWD-execution vector) and relative segments (which would leak a non-absolute `path`).
+    if (!dir.startsWith('/')) continue;
+    const cand = join(dir, bin);
+    try {
+      // X_OK alone also passes for a DIRECTORY named `bin` (dirs carry the search bit); the OS's own
+      // execvp skips such a directory and searches on, so require a regular file to match that and
+      // avoid returning a dir that execFile would then reject with EACCES (a false installed:true).
+      accessSync(cand, constants.X_OK);
+      if (statSync(cand).isFile()) return cand;
+    } catch { /* missing, not executable, or not a regular file — keep scanning */ }
+  }
+  return bin;
 }
 
 function authState(spec: AgentSpec): { authed: boolean; method?: string } {
@@ -196,7 +254,10 @@ function authState(spec: AgentSpec): { authed: boolean; method?: string } {
   }
   if (spec.keychainService) {
     try {
-      execFileSync('security', ['find-generic-password', '-s', spec.keychainService], { stdio: 'ignore' });
+      // timeout: a headless/SSH/locked-keychain session (the same non-interactive launch context
+      // as #78) can make `security` block on an ACL prompt; bound it so detection can't hang the
+      // event loop. A timeout throws → treated as "not in keychain" (fail-open, same as absence).
+      execFileSync('security', ['find-generic-password', '-s', spec.keychainService], { stdio: 'ignore', timeout: 2000 });
       return { authed: true, method: 'keychain' };
     } catch { /* not in keychain */ }
   }
@@ -208,8 +269,12 @@ function detectOne(spec: AgentSpec): Promise<AgentDetection> {
     id: spec.id, label: spec.label, vendor: spec.vendor, bin: spec.bin,
     blurb: spec.blurb, invokeHint: spec.invokeHint,
   };
+  // Resolve against PATH + well-known install dirs so a Finder/desktop launch's minimal PATH
+  // doesn't hide an installed CLI (issue #78). Absolute when found; the bare name otherwise
+  // (→ execFile throws the same ENOENT → installed:false, preserving the true-absence path).
+  const exe = resolveBin(spec.bin);
   return new Promise((resolve) => {
-    execFile(spec.bin, spec.versionArgs, { timeout: 8000 }, (err, stdout) => {
+    execFile(exe, spec.versionArgs, { timeout: 8000 }, (err, stdout) => {
       if (err && (err as NodeJS.ErrnoException).code === 'ENOENT') {
         resolve({ ...base, installed: false, authed: false, ready: false });
         return;
@@ -220,7 +285,7 @@ function detectOne(spec: AgentSpec): Promise<AgentDetection> {
       resolve({
         ...base,
         installed: true,
-        path: resolvePath(spec.bin),
+        path: exe !== spec.bin ? exe : undefined,
         version,
         authed: auth.authed,
         authMethod: auth.method,
@@ -277,7 +342,9 @@ export function runLocalAgent(
   const env = childEnv();
   return new Promise((resolve) => {
     // stdin:'ignore' so the agent doesn't stall waiting on piped input (e.g. `claude -p`'s 3s stdin wait).
-    const child = spawn(spec.bin, args, { env, stdio: ['ignore', 'pipe', 'pipe'] });
+    // resolveBin: same PATH-robust resolution the detector uses, so a CLI detected under a minimal
+    // launchd PATH also SPAWNS (detected-but-unspawnable would be worse than undetected) — issue #78.
+    const child = spawn(resolveBin(spec.bin), args, { env, stdio: ['ignore', 'pipe', 'pipe'] });
     let out = '';
     let errOut = '';
     let done = false;
@@ -340,7 +407,8 @@ export function localAgentChat(id: string, prompt: string, opts: { model?: strin
 
   const cleanup = () => { if (workDir) { try { rmSync(workDir, { recursive: true, force: true }); } catch { /* noop */ } } };
   return new Promise((resolve, reject) => {
-    const child = spawn(spec.bin, args, { env, stdio: [viaStdin ? 'pipe' : 'ignore', 'pipe', 'pipe'] });
+    // resolveBin: PATH-robust resolution (issue #78) — see runLocalAgent.
+    const child = spawn(resolveBin(spec.bin), args, { env, stdio: [viaStdin ? 'pipe' : 'ignore', 'pipe', 'pipe'] });
     let out = '';
     let errOut = '';
     let done = false;