What causes "${source} is not valid JSON: ${error.message}" in affaan-m/ECC?

Run `node -e "JSON.parse(require('fs').readFileSync('.claude-plugin/plugin.json','utf8'))"` (and the marketplace.json equivalent) to surface the exact parse error and line.

affaan-m/ECC · error · Error

${source} is not valid JSON: ${error.message}

Error message

${source} is not valid JSON: ${error.message}

What it means

`parseCatalogDescriptionExpectations` reads `.claude-plugin/plugin.json` (source = `.claude-plugin/plugin.json description`, getDescription = `parsed => parsed.description`) or `.claude-plugin/marketplace.json` (source = `.claude-plugin/marketplace.json plugin description`, getDescription = `parsed => parsed.plugins?.[0]?.description`). It first JSON-parses the file; a parse failure throws `${source} is not valid JSON: <error.message>`. This is a structural JSON error in the plugin manifest, not a count-mismatch.

Source

Thrown at scripts/ci/catalog.js:336

    }

    expectations.push({
      category: pattern.category,
      mode: pattern.mode === 'minimum' && match[2] ? 'minimum' : pattern.mode,
      expected: Number(match[1]),
      source: `${pattern.source} (${pattern.category})`
    });
  }

  return expectations;
}

function parseCatalogDescriptionExpectations(content, source, getDescription) {
  let parsed;
  try {
    parsed = JSON.parse(content);
  } catch (error) {
    throw new Error(`${source} is not valid JSON: ${error.message}`);
  }

  const description = getDescription(parsed);
  if (typeof description !== 'string') {
    throw new Error(`${source} is missing the catalog count description`);
  }

  const match = description.match(/(\d+)\s+agents,\s+(\d+)\s+skills,\s+(\d+)\s+legacy command shims?/i);
  if (!match) {
    throw new Error(`${source} is missing the catalog count description`);
  }

  return [
    { category: 'agents', mode: 'exact', expected: Number(match[1]), source },
    { category: 'skills', mode: 'exact', expected: Number(match[2]), source },
    { category: 'commands', mode: 'exact', expected: Number(match[3]), source },
  ];
}

View on GitHub (pinned to 01e15490f0)

Solutions

Run `node -e "JSON.parse(require('fs').readFileSync('.claude-plugin/plugin.json','utf8'))"` (and the marketplace.json equivalent) to surface the exact parse error and line.
Fix the JSON syntax error — remove trailing commas, quote all keys, remove comments, escape control characters.
Validate with `npx jsonlint .claude-plugin/plugin.json` or a JSON schema validator.
Re-run `node scripts/ci/catalog.js` to confirm the JSON parses.

Example fix

// before (.claude-plugin/plugin.json — trailing comma)
{
  "name": "ecc",
  "version": "2.2.0",
  "description": "...68 agents, 284 skills, 94 legacy command shims",
}

// after
{
  "name": "ecc",
  "version": "2.2.0",
  "description": "...68 agents, 284 skills, 94 legacy command shims"
}

Defensive patterns

Strategy: try-catch

Validate before calling

const fs = require('fs');
for (const p of ['.claude-plugin/plugin.json', '.claude-plugin/marketplace.json']) {
  try {
    JSON.parse(fs.readFileSync(p, 'utf8'));
  } catch (e) {
    console.error(`${p} is not valid JSON: ${e.message}`);
    process.exit(1);
  }
}

Type guard

function isValidPluginJson(content) {
  try { JSON.parse(content); return true; } catch { return false; }
}

Try / catch

try {
  runCatalogCheck();
} catch (error) {
  if (/is not valid JSON/i.test(error.message)) {
    console.error('Plugin manifest JSON is malformed. Run: node -e "JSON.parse(require(\'fs\').readFileSync(process.argv[1],\'utf8\'))" <file>');
  }
  throw error;
}

Prevention

Never hand-edit JSON with a text editor that strips quotes or allows comments — use a JSON-aware editor.
Add `jsonlint` or a JSON schema check to pre-commit.
Resolve merge conflicts in JSON files fully (remove conflict markers) before committing.
Avoid trailing commas and unquoted keys.

When it happens

Trigger: Triggered when running the catalog check and either `.claude-plugin/plugin.json` or `.claude-plugin/marketplace.json` contains a JSON syntax error: trailing comma, unquoted key, single-quoted string, unescaped control char, BOM, or a hand-edit that broke the structure.

Common situations: A maintainer hand-edits plugin.json to bump a field and leaves a trailing comma or comment. A merge conflict marker is left inside the JSON. marketplace.json's plugins array is restructured. An editor inserts a BOM. The file is saved with CRLF and a stray character.

Related errors

AI-assisted analysis of affaan-m/ECC@01e15490f0 (2026-08-13). Data as JSON: /api/errors/3c6cfe82b4df3c70. Report an issue: GitHub.