Nodiom

nodiom

Address any node in your Markdown.

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Markdown has structure. Every tool ignores it. Nodiom doesn't.

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The Problem

When an AI agent or any program needs to modify a Markdown document, it loads the whole file as a string, uses fragile regex to find the right section, splices in new content, and hopes the formatting didn't break.

Nodiom solves this by treating Markdown as what it actually is: a tree. Every heading creates a branch, every list item is a node. You address them with path-like selectors — the same way you'd query a DOM node or a database row.

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Quick Example

import { Nodiom } from '@synexiom-labs/nodiom';

const doc = await Nodiom.fromFile('./project-wiki.md');

// Read everything under a heading
const tasks = doc.read('# Project Alpha > ## Active Tasks');

// Add a new task
doc.append('# Project Alpha > ## Active Tasks', '- [ ] Deploy to staging');

// Remove a completed item
doc.delete('# Project Alpha > ## Completed > li[0]');

// Save back to disk
await doc.save();

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Install

npm install @synexiom-labs/nodiom

Requirements: Node.js 18+

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Core Concepts: Selectors

A selector is a " > "-separated path of segments, each matching a node in the document's structure.

Heading segments

"# Project Alpha"              → The H1 "Project Alpha" and all its content
"## Tasks"                     → Any top-level H2 named "Tasks"
"# Project Alpha > ## Tasks"   → The H2 "Tasks" nested under H1 "Project Alpha"

The depth of the # characters must match the heading depth in the document.

Element segments

"## Tasks > li[0]"     → First list item under ## Tasks
"## Tasks > li[-1]"    → Last list item (negative indexing)
"## Notes > p[0]"      → First paragraph under ## Notes
"## Arch > table[0]"   → First table under ## Architecture
"## Arch > code[0]"    → First code block under ## Architecture

Valid element types: p, li, code, blockquote, table, hr

Heading scope semantics

"Content under ## Tasks" means all nodes that appear after the ## Tasks heading until the next heading of equal or lesser depth. This matches how you naturally read a Markdown document.

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API Reference

Initialization

// From a file
const doc = await Nodiom.fromFile('./wiki.md');

// From a file with advisory locking (for concurrent access)
const doc = await Nodiom.fromFile('./wiki.md', { lock: true, lockTimeout: 5000 });

// From a string (no filesystem — safe for serverless)
const doc = Nodiom.fromString(markdownContent);

Reading

// Returns the Markdown string of everything under the selector
const content: string = doc.read('# Project > ## Summary');

// Returns an array of list item strings
const items: string[] = doc.readList('# Project > ## Tasks');

// Returns metadata about the location
const info = doc.query('# Project > ## Tasks');
// { exists: true, type: 'heading', depth: 2, childCount: 7, index: 3 }

// Returns the structural outline of the document
const outline = doc.tree();
// [{ heading: 'Project', depth: 1, children: [{ heading: 'Tasks', depth: 2, children: [] }] }]

Mutating

All mutation methods return this, so they can be chained.

// Replace all content within a section (heading is preserved)
doc.write('# Project > ## Summary', 'The project is on track for Q3.');

// Append content after the last item in a section
doc.append('# Project > ## Tasks', '- [ ] Final review');

// Remove a node
doc.delete('# Project > ## Completed > li[0]');

// Chaining
doc
  .append('# Project > ## Tasks', '- [ ] Task A')
  .append('# Project > ## Tasks', '- [ ] Task B')
  .delete('# Project > ## Completed > li[-1]');

Serialization & File I/O

// Get the current document as a Markdown string
const output: string = doc.toString();

// Write back to the original file (releases lock if held)
await doc.save();

// Write to a new file
await doc.saveAs('./output.md');

// Explicitly release a lock
await doc.unlock();

Error Handling

import { SelectorNotFoundError, SelectorParseError, LockError } from '@synexiom-labs/nodiom';

try {
  doc.read('# Project > ## Taks'); // typo
} catch (e) {
  if (e instanceof SelectorNotFoundError) {
    console.log(e.selector);     // "# Project > ## Taks"
    console.log(e.suggestions);  // ["Tasks"] — fuzzy match
  }
}

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AI Agent Example

A LangChain-style agent maintaining a project wiki:

import { Nodiom } from '@synexiom-labs/nodiom';

async function agentUpdateWiki(wikiPath: string, taskDescription: string) {
  // Load with lock — safe for concurrent agent access on the same machine
  const doc = await Nodiom.fromFile(wikiPath, { lock: true });

  // Add a new active task
  doc.append('## Tasks > ### Active', `- [ ] ${taskDescription}`);

  // Log the current task count
  const activeTasks = doc.readList('## Tasks > ### Active');
  console.log(`Active tasks: ${activeTasks.length}`);

  // Save and release the lock
  await doc.save();
}

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Concurrency

Nodiom includes advisory file locking via proper-lockfile.

const doc = await Nodiom.fromFile('./shared-wiki.md', { lock: true });
// Other Nodiom processes trying to lock this file will wait or throw LockError

doc.append('## Log', `- ${new Date().toISOString()} Agent B completed task`);
await doc.save(); // writes and releases the lock

Scope of the concurrency guarantee: Advisory locking prevents corruption from multiple Node.js processes on the same machine. For distributed multi-agent environments (multiple machines or serverless functions), use Nodiom Cloud (coming soon) which provides true distributed concurrency with structural merge semantics.

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Comparison

| Approach | Structured reads? | Structural writes? | Roundtrip fidelity | Serverless | Concurrent | |---|---|---|---|---|---| | fs.readFile + regex | No | Fragile | Depends on regex | No | No | | gray-matter | Frontmatter only | Frontmatter only | Yes | Yes | No | | Databases | No | No | No (loses Markdown) | Yes | Yes | | Vector DBs | Semantic only | No | No | Yes | Yes | | Nodiom | Yes | Yes | Yes | Yes | Single-machine |

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Roadmap

• v0.2.0 — insert() with positional control (before / after a sibling), diff() structural diffing, glob selectors (## *Tasks*)
• v0.3.0 — LangChain tool wrapper
• v1.0.0 — Stable selector syntax, production-ready API
• Nodiom Cloud — Hosted HTTP API for serverless and distributed multi-agent use. No local setup required. Join the waitlist →

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Contributing

Contributions welcome. Please open an issue before submitting a PR for non-trivial changes.

git clone https://github.com/synexiom-labs/nodiom
cd nodiom
npm install
npm test

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License

MIT — Synexiom Labs Inc.

Born from the state layer powering Cortexiom's reasoning architecture.

Source & license

This open-source MCP server is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: Synexiom-Labs
• Source: Synexiom-Labs/nodiom
• License: MIT
• Homepage: https://www.npmjs.com/package/nodiom

Install and usage instructions live in the source repository linked above.