fix(install): strip ecc: plugin namespace from manual Claude installs

The ecc@ecc plugin namespaces agents, commands and skills as `ecc:<name>`.
A manual install (install-apply --target claude|claude-project) places the
same files at bare names under ~/.claude, so plugin-prefixed references in
copied markdown point at agents and commands that do not exist in that
layout (e.g. subagent_type "ecc:planner", frontmatter agent: ecc:...).

- Add plugin-namespace.js with stripPluginNamespace(), which removes the
  `ecc:` prefix before an identifier and leaves `ecc@ecc`, URLs and words
  ending in "ecc" alone.
- Apply it to markdown copy operations when the target is claude or
  claude-project. Non-markdown files and other targets are unchanged.
- Reword the agents rule so it describes both install modes instead of
  stating that agents only ship with the plugin.
- Cover the transform with tests/lib/install-plugin-namespace.test.js.

rules/common/agents.md

@@ -2,8 +2,8 @@
 
 ## Available Agents
 
-ECC agents ship with the `ecc@ecc` plugin, not in `~/.claude/agents/`.
-They are invoked through the Agent tool with a plugin-scoped `subagent_type`:
+ECC agents come either from the `ecc@ecc` plugin (plugin-scoped names, `ecc:<name>`) or from a manual install into `~/.claude/agents/` (bare names, `<name>`). Use the name that matches the install you have; the manual installer strips the `ecc:` prefix from copied files.
+They are invoked through the Agent tool with that `subagent_type`:
 
 ```text
 Agent(subagent_type: "ecc:planner", prompt: "...")

scripts/lib/install/apply.js

@@ -51,6 +51,11 @@ const {
   prepareExcludedPathsReconciliation,
 } = require('./excluded-paths-reconciliation');
 const { buildInstallIndex, rewriteRelativeLinks } = require('./link-rewrite');
+const { stripPluginNamespace } = require('./plugin-namespace');
+
+// Manual installs place agents, commands and skills at bare names; the
+// ecc@ecc plugin namespaces them as `ecc:<name>`.
+const MANUAL_CLAUDE_TARGETS = new Set(['claude', 'claude-project']);
 const { adaptAntigravityAgent } = require('./antigravity-agent');
 
 function isMarkdownPath(filePath) {
@@ -874,13 +879,16 @@ function applyInstallPlanLocked(plan, dependencies = {}, settingsLockHeld = fals
         && operation.sourceRelativePath
         && isMarkdownPath(operation.destinationPath)
       );
-      if (operation.kind === 'copy-file' && (operation.contentTransform || needsLinkRewrite)) {
+      const stripNamespace = MANUAL_CLAUDE_TARGETS.has(plan.adapter?.target)
+        && isMarkdownPath(operation.destinationPath);
+      if (operation.kind === 'copy-file' && (operation.contentTransform || needsLinkRewrite || stripNamespace)) {
         const transformed = transformInstallContent(
           operation,
           fs.readFileSync(operation.sourcePath, 'utf8')
         );
+        const namespaced = stripNamespace ? stripPluginNamespace(transformed) : transformed;
         const installedContent = needsLinkRewrite
-          ? rewriteRelativeLinks(transformed, {
+          ? rewriteRelativeLinks(namespaced, {
             sourceRel: operation.sourceRelativePath,
             index: linkIndex,
           })

scripts/lib/install/plugin-namespace.js

@@ -0,0 +1,19 @@
+'use strict';
+
+// The ecc@ecc plugin exposes agents, commands and skills under an `ecc:`
+// namespace (`ecc:planner`, `/ecc:plan`). A manual install
+// (install-apply --target claude|claude-project) places the same files at bare
+// names, so plugin-prefixed references in copied markdown must drop the prefix
+// or they point at agents and commands that do not exist in that layout.
+//
+// The leading guard keeps `ecc@ecc` and words that merely end in "ecc" (e.g.
+// "decc:") untouched; the lookahead requires a real identifier after the colon.
+const PLUGIN_NAMESPACE_PREFIX = /(^|[^A-Za-z0-9_@.-])ecc:(?=[a-z][a-z0-9-]*)/gm;
+
+function stripPluginNamespace(content) {
+  return String(content).replace(PLUGIN_NAMESPACE_PREFIX, '$1');
+}
+
+module.exports = {
+  stripPluginNamespace,
+};

tests/lib/install-plugin-namespace.test.js

@@ -0,0 +1,86 @@
+/**
+ * Tests for scripts/lib/install/plugin-namespace.js — manual Claude installs
+ * place agents, commands and skills at bare names, so plugin-prefixed
+ * `ecc:<name>` references in copied markdown must lose the prefix.
+ */
+
+'use strict';
+
+const assert = require('assert');
+
+const { stripPluginNamespace } = require('../../scripts/lib/install/plugin-namespace');
+
+function test(name, fn) {
+  try {
+    fn();
+    console.log(`  PASS ${name}`);
+    return true;
+  } catch (error) {
+    console.log(`  FAIL ${name}`);
+    console.log(`    Error: ${error.message}`);
+    console.error(error.stack || error);
+    return false;
+  }
+}
+
+function runTests() {
+  console.log('Running install plugin-namespace tests...\n');
+  let passed = 0;
+  let failed = 0;
+  const record = ok => (ok ? passed++ : failed++);
+
+  record(test('strips the prefix from agent names in code spans, bold and tables', () => {
+    const input = [
+      '| ecc:planner | Planning |',
+      '1. Use **ecc:code-reviewer** agent',
+      'Use `ecc:tdd-guide` here',
+    ].join('\n');
+    assert.strictEqual(stripPluginNamespace(input), [
+      '| planner | Planning |',
+      '1. Use **code-reviewer** agent',
+      'Use `tdd-guide` here',
+    ].join('\n'));
+  }));
+
+  record(test('strips the prefix from agent frontmatter and tool-call arguments', () => {
+    assert.strictEqual(
+      stripPluginNamespace('agent: ecc:security-reviewer'),
+      'agent: security-reviewer'
+    );
+    assert.strictEqual(
+      stripPluginNamespace('Agent(subagent_type: "ecc:planner", prompt: "...")'),
+      'Agent(subagent_type: "planner", prompt: "...")'
+    );
+  }));
+
+  record(test('strips the prefix from slash commands', () => {
+    assert.strictEqual(stripPluginNamespace('see `/ecc:ecc-guide`'), 'see `/ecc-guide`');
+    assert.strictEqual(stripPluginNamespace('/ecc:plan "Add auth"'), '/plan "Add auth"');
+  }));
+
+  record(test('leaves the plugin identifier ecc@ecc untouched', () => {
+    const input = '`/plugin install ecc@ecc` and `ecc@ecc`';
+    assert.strictEqual(stripPluginNamespace(input), input);
+  }));
+
+  record(test('leaves words that only end in "ecc" untouched', () => {
+    const input = 'the decc:thing and tecc:value';
+    assert.strictEqual(stripPluginNamespace(input), input);
+  }));
+
+  record(test('does not touch a colon with no identifier after it', () => {
+    const input = 'the `ecc:` prefix in plugin mode';
+    assert.strictEqual(stripPluginNamespace(input), input);
+  }));
+
+  record(test('returns content with no prefix unchanged', () => {
+    const input = '# Plain markdown\n\nNo namespace here.\n';
+    assert.strictEqual(stripPluginNamespace(input), input);
+  }));
+
+  console.log(`\nResults: Passed: ${passed}, Failed: ${failed}`);
+  return failed === 0;
+}
+
+const ok = runTests();
+process.exit(ok ? 0 : 1);