forkmind MCP server

ForkMind 🧠

Local-first LLM branching, debugging & context offloading

Treat your AI conversation history like a Git repository — capture every call, branch from any turn, and diff outcomes side by side. All on your machine.

Try in 10s · Features · Install · Quick start · MCP · Capsules

What you're seeing: the conversation DAG with a fork off the debug turn, the node inspector (request/response, tokens, provenance), and the ⇄ Compare view diffing two branches with per-token deltas. The green ● streaming badge shows live capture — nodes appear as they're recorded.

ForkMind captures every LLM call into a local .forkmind/ directory, visualizes the conversation as a Directed Acyclic Graph (DAG), and lets you branch, diff, and replay from any point in the history. Works with any OpenAI-compatible API, defaulting to free, open-source models via Ollama — also Anthropic, Groq, OpenRouter, Together, vLLM, and LM Studio.

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Why

Debugging agentic / tool-calling flows means re-running the same prompt with tiny tweaks over and over, then scrolling through terminal logs to see what changed. ForkMind records each run as a node in a conversation tree, so instead of re-reading logs you see the whole history, branch from any turn, and compare outcomes visually.

Everything is plain JSON on disk. No database, no account, no telemetry — nothing leaves your machine except the LLM call you were already making.

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Features

• Capture — every LLM call is recorded to a plain JSON node under .forkmind/. Works from any language via an OpenAI-compatible proxy; streaming responses are reconstructed (text and fragmented tool-call args).
• DAG dashboard — a React Flow canvas draws the whole conversation as a tree: every turn, tool call, model, and token count, with the node inspector one click away.
• Live capture stream — nodes pulse into the DAG the instant they're recorded (Server-Sent Events), so you can watch an agent think in real time.
• Branch — fork any historical turn: edit the prompt or swap the model and re-run, linked to the original as a visible branch.
• ⇄ Compare — pick any two nodes for a side-by-side, word-level diff of prompts and responses, plus a token-usage table with per-field deltas. "Git diff for LLM outputs."
• ⏪ Time-travel replay — re-run a whole chain from an edited node; the regenerated turns land as a sibling branch while your original user turns and tool results re-apply in order.
• MCP server — agents query their own .forkmind/ history mid-task (recall what they tried, trace how they got somewhere, self-correct).
• Regression testing — pin a known-good output as a baseline, re-run it after prompt/model changes, and catch drift with free offline checks (contains / regex / similarity), tool-call assertions, or an opt-in LLM judge graded against your own rubric. CI-ready.
• Trajectory regression — pin a whole multi-turn agent path from the captured graph and replay it, so a prompt change that reroutes an agent mid-run gets caught even when the final answer still reads fine.
• Context capsules — offload context into encrypted, immutable DAG capsules; restore in full or per segment; replicate (RAID), export/import, crypto-shred.
• forkmind demo — one command opens the dashboard on a pre-seeded sample DAG, zero setup and zero API key.

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Try it in 10 seconds

npx forkmind demo

No API key, no setup: the dashboard opens with a pre-seeded conversation DAG — a coding-agent debug session that forks into a failed fix and a winning fix, plus an archived context capsule. Everything lives in a throwaway temp directory; your project is never touched. If a local Ollama is running, Fork from here works live against your local model.

Once you're in, try:

• ⇄ Compare any two nodes for a side-by-side, word-level diff of prompts, responses, and token usage — "git diff for LLM outputs".
• ⏪ Replay from here to re-run a whole chain from an edited node; the regenerated turns land as a sibling branch.
• Live capture — nodes pulse into the DAG the instant they're recorded, so you can watch an agent think in real time.

Install

# Run without installing (published on npm)
npx forkmind init
npx forkmind start

# …or install the CLI globally
npm install -g forkmind
forkmind start

No npm registry needed either — ForkMind runs straight from the git link, and the dashboard builds automatically on install:

# Run without installing, from GitHub
npx github:medhovarsh/forkmind init
npx github:medhovarsh/forkmind start

# …or clone to hack on it
git clone https://github.com/medhovarsh/forkmind
cd forkmind && npm install

Install as a Claude Code plugin

ForkMind ships a Claude Code plugin (skill + /forkmind command) so Claude knows when and how to drive it — same install flow as any marketplace plugin:

/plugin marketplace add Medhovarsh/forkmind
/plugin install forkmind

The plugin bundles:

• forkmind skill — Claude reaches for ForkMind whenever you ask it to debug a prompt, compare models, branch from a past turn, or regression-test a call.
• /forkmind command — start / branch / test / mcp on demand.
• forkmind-debugger agent — runs model/prompt comparisons in an isolated context and returns a compact verdict instead of dumping transcripts.
• MCP server, auto-wired — agents query their own .forkmind/ history (recall attempts, trace lineage, self-correct) with zero manual config.

The CLI is still what runs the proxy + dashboard; the plugin is the glue that teaches Claude to use it.

Quick start (free, no API key)

# 1. Install a free local model
#    (install Ollama from https://ollama.com first)
ollama pull llama3

# 2. Init + start ForkMind
npx github:medhovarsh/forkmind init    # create .forkmind/ in your project
npx github:medhovarsh/forkmind start   # proxy on http://localhost:4500 + dashboard

# 3. Point your code at the proxy (see SDK below), make some calls

# 4. Open the dashboard
open http://localhost:4500

Drop-in SDK (auto-builds the tree)

npm i openai            # the wrapper extends the official SDK

const { ForkMindOpenAI } = require('forkmind');

const client = new ForkMindOpenAI({
  apiKey: 'ollama',                       // ignored by Ollama; required by SDK
  upstream: 'http://localhost:11434',     // free local open-source models
});

// Each call is recorded; sequential calls auto-chain into a conversation tree.
const res = await client.chat.completions.create({
  model: 'llama3',
  messages: [{ role: 'user', content: 'Explain backpropagation simply.' }],
});

Run the full example:

node examples/chain.js

Any language — point your client at the proxy

The SDK wrapper is convenience, not a requirement. ForkMind's proxy speaks the OpenAI-compatible wire protocol, so capture works from any language: set your client's base URL to http://localhost:4500/v1 and you're recorded. Chain turns into a tree by passing back the x-forkmind-node-id from the previous response as the next request's x-forkmind-parent header (the JS wrapper just automates this).

# Python — official openai client, zero ForkMind code
from openai import OpenAI

client = OpenAI(base_url="http://localhost:4500/v1", api_key="ollama")
res = client.chat.completions.create(
    model="llama3",
    messages=[{"role": "user", "content": "Explain backpropagation simply."}],
    extra_headers={"x-forkmind-upstream": "http://localhost:11434"},
)
# read res via .with_raw_response to grab x-forkmind-node-id and chain the next call

# curl — anything that can POST JSON
curl http://localhost:4500/v1/chat/completions \
  -H 'content-type: application/json' \
  -H 'x-forkmind-upstream: http://localhost:11434' \
  -d '{"model":"llama3","messages":[{"role":"user","content":"hi"}]}' -i
# response header `x-forkmind-node-id: <id>` → pass as `x-forkmind-parent` next call

Go, Ruby, Rust, Java — same deal: base URL + the two headers. The dashboard, branching, MCP, and regression testing all work regardless of source language.

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Framework integrations

ForkMind ships thin adapters for the two biggest JS LLM ecosystems. Both route through the same proxy, so capture, branching, the dashboard, MCP, and regression all work unchanged — no model-class swap, no callbacks.

LangChain.js

npm i @langchain/openai @langchain/core

const { ChatOpenAI } = require('@langchain/openai');
const { forkmind } = require('forkmind/langchain');

const fm = forkmind({ upstream: 'http://localhost:11434' }); // free local Ollama
const model = new ChatOpenAI({
  apiKey: 'ollama',
  model: 'llama3',
  configuration: fm.configuration, // baseURL → proxy + chaining fetch
});

await model.invoke('Explain backpropagation simply.');
// sequential calls on `fm` auto-chain; fm.setParent(id) to branch from a node.

Vercel AI SDK

npm i ai @ai-sdk/openai

const { generateText } = require('ai');
const { forkmindOpenAI } = require('forkmind/vercel');

const openai = forkmindOpenAI({ upstream: 'http://localhost:11434' });
const { text } = await generateText({
  model: openai('llama3'),
  prompt: 'Explain backpropagation simply.',
});
// openai.setParent(id) / openai.resetParent() control the branch point.

Both honor FORKMIND_PROXY (proxy base URL) and take an explicit baseURL / upstream per instance.

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Using other free / open providers

ForkMind is provider-agnostic — it forwards your auth headers verbatim and lets you set the upstream per client. Anything OpenAI-compatible just works:

Provider	upstream	apiKey
Ollama (local)	http://localhost:11434	any string
LM Studio (local)	http://localhost:1234	any string
Groq (free tier)	https://api.groq.com/openai	gsk_...
OpenRouter	https://openrouter.ai/api	sk-or-...
Together	https://api.together.xyz	your key
OpenAI	https://api.openai.com (default)	sk-...

new ForkMindOpenAI({ apiKey: process.env.GROQ_API_KEY,
                     upstream: 'https://api.groq.com/openai' });

You can also override per request with the x-forkmind-upstream header if you call the proxy directly instead of via the SDK.

Anthropic (Claude)

npm i @anthropic-ai/sdk

const { ForkMindAnthropic } = require('forkmind');
const client = new ForkMindAnthropic({ apiKey: process.env.ANTHROPIC_API_KEY });
await client.messages.create({ model: 'claude-3-5-sonnet-latest', max_tokens: 512,
                               messages: [{ role: 'user', content: 'hi' }] });

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How it works

your app ──▶ ForkMindOpenAI (baseURL = localhost:4500/v1)
                │  injects x-forkmind-parent
                ▼
         ForkMind proxy (Express, :4500)
                │  forwards verbatim (your key, your upstream)
                ▼
         provider (Ollama / Groq / OpenAI / ...)
                │  response
                ▼
         proxy reconstructs + saveNode()  ──▶  .forkmind/nodes/<id>.json
                │  returns x-forkmind-node-id
                ▼
         wrapper chains it as the next call's parent

• Deterministic node IDs. sha256(request + parentId) → first 12 hex chars. Same prompt under the same parent collapses to one node. The ID doesn't depend on the response, so it can be returned as a header even before a streamed body finishes.
• Streaming. Bytes pass through to your app untouched (real SSE); the proxy tees them, reconstructs the full message (text and fragmented tool-call arguments), and saves the node on stream end.
• Branching. Each node records its provider + upstream, so "Fork from here" in the dashboard replays the edited request to the same host, linked to the historical parent.
• Compare. Any two nodes diff side by side — word-level prompt/response changes and a token table with signed deltas — computed client-side from the captured JSON (dashboard/src/lib/diff.js).
• Replay. POST /api/replay walks a captured lineage from an edited node to a chosen leaf, regenerating each assistant turn against the modified history while original user turns and tool results re-apply verbatim. The new chain is saved as a sibling branch.
• Live stream. saveNode emits on an in-process bus; GET /api/stream relays each new node to the dashboard over SSE, so the canvas updates without polling.

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MCP — let agents query their own history

ForkMind ships an MCP server so an AI agent can read its own .forkmind/ history mid-task and self-correct — recall what it already tried, see how it reached a state, or search past attempts.

forkmind mcp          # stdio MCP server (or: forkmind-mcp)

One-line install via Smithery (configured in smithery.yaml) — run it from your project root so it sees your .forkmind/:

npx -y @smithery/cli install forkmind --client claude

…or register it manually with any MCP client (Claude Desktop / Claude Code / Cursor / Cline):

{
  "mcpServers": {
    "forkmind": {
      "command": "npx",
      "args": ["-y", "github:medhovarsh/forkmind", "mcp"]
    }
  }
}

Tools exposed:

Tool	Purpose
forkmind_recent	Newest captured turns (compact)
forkmind_get_node	Full request + response for one node
forkmind_lineage	Root→node path — the exact context that produced a state
forkmind_children	Sibling branches forking from a node
forkmind_search	Substring search across all requests/responses
forkmind_stats	Tree totals: nodes, roots, leaves, providers
forkmind_context_save	Offload context into an encrypted DAG capsule
forkmind_context_list	List saved capsules (title, digest, size, age)
forkmind_context_digest	Digest + segment map — cheap pre-restore probe
forkmind_context_restore	Full or per-segment restore, integrity-verified
forkmind_context_forget	Irreversible crypto-shred (requires id echo)
forkmind_context_replicas	Replica (RAID) health, optional sync
forkmind_context_stats	Aggregate stats: count, bytes, estimated tokens
forkmind_context_export	Portable passphrase-encrypted bundle
forkmind_context_import	Import + re-verify a bundle, re-wrap locally

The server reads the .forkmind/ in its working directory — point the client's cwd at your project.

Context capsules — offload context as an encrypted DAG

Most context managers treat a full window as a cache-eviction problem: truncate and lose it. ForkMind capsules invert that — persist first, verify, then compact. A capsule is an immutable, content-addressed DAG of context segments, AES-256-GCM encrypted on disk, restorable in full or one segment at a time.

# Save (items JSON from a file or stdin), get back a 12-char handle
echo '{"title":"auth debug","items":[{"role":"user","content":"..."}]}' \
  | forkmind context save --digest "oauth loop root-caused; fix in token.js"

forkmind context list                 # all capsules, newest first
forkmind context show 9f3ac21b7e04    # decrypt + verify + print
forkmind context verify 9f3ac21b7e04  # DAG integrity: parents, acyclicity, hashes
forkmind context forget 9f3ac21b7e04 --confirm 9f3ac21b7e04   # crypto-shred

Same engine over HTTP (POST/GET/DELETE :4500/api/context…) and via five MCP tools, so agents can archive their own context mid-task and pull it back later. The Claude Code plugin ships a forkmind-archivist skill + subagent that teaches Claude the offload contract: save → verify on disk → only then drop it from the window.

Guarantees:

• Immutable & acyclic by construction — segment ids are hashes over content + parents (Git-style); a cycle would require a hash to contain itself.
• No plaintext at rest — per-capsule keys, wrapped by a master key stored outside .forkmind/ (~/.forkmind-keys/); an accidentally committed .forkmind/ leaks only ciphertext and structure.
• Digests are opt-in — the agent writes a ≤5-line retrieval summary, or omits it entirely for private capsules.
• Forgetting is real — delete destroys the key first (crypto-shredding), then tombstones the id so identical content can never resurrect it.
• The model is never touched — capsules operate on what the client sends; provider, weights, and KV cache are out of scope by design.

RAID — Redundant Array of Independent DAGs

Mirror capsules to any number of extra filesystem targets (second disk, synced folder, network mount). Replicas hold ciphertext + manifests only — keys are never replicated. If the primary copy is lost or bit-rots, restore self-heals from the first replica that passes verification; healed copies get no trust shortcut (full integrity check still runs).

forkmind context replicas add D:\backup\forkmind   # add target + sync
forkmind context replicas list                     # coverage per target
forkmind context replicas sync                     # catch up offline targets,
                                                   # propagate tombstones

Forgetting reaches every copy: reachable replicas are shredded immediately; a replica that was offline gets its stale ciphertext removed on the next sync (tombstone propagation) — and it was unreadable anyway, since the capsule key died at forget time. Tombstones also make heal refuse to resurrect anything forgotten.

Portable export/import

Move a capsule to another machine or project — a laptop that doesn't share this project's ~/.forkmind-keys/ master key, a teammate, cold storage:

forkmind context export 9f3ac21b7e04 --passphrase "correct horse battery staple" --out capsule.json
# ... move capsule.json anywhere ...
forkmind context import capsule.json --passphrase "correct horse battery staple"

The bundle carries its own scrypt-derived key material (N=32768, deliberately slow to resist offline brute force of a weak passphrase) — it never depends on the source machine's master key, and the passphrase is never written into the bundle itself. On import, every segment is independently re-verified (recomputed id, recomputed hash, resolved parents, acyclic DFS) before anything touches disk — the bundle is never trusted blindly, only proven. Import is idempotent and honors tombstones, same as a fresh save.

Archive straight from the capture DAG

The two halves connect: any conversation the proxy captured can be archived into a capsule in one move — no manual JSON assembly — and restored later as a provider-ready messages[] array, ready to splice into the next request:

# archive the whole lineage ending at a captured turn
forkmind context save --from-node a1b2c3d4e5f6 --digest "auth debug, resolved"

# restore as chat messages (or GET /api/context/:id/messages)
forkmind context show 9f3ac21b7e04 --messages

Same via MCP: forkmind_context_save { fromNodeId } and forkmind_context_restore { asMessages: true } — an agent can archive its own captured history mid-task and splice it back whenever needed. Capsules keep sourceNodeIds links back into the turn DAG.

Token savings

forkmind context save and forkmind context stats report an estimated token count freed from your context window (~4 bytes/token, the standard rough heuristic) — a concrete number for how much a capsule actually saved.

Regression testing — pin good outputs, catch degradation

Tweaking a system prompt or swapping a model can silently degrade results. ForkMind lets you pin a known-good captured node as a baseline, then re-run its exact request later and check the new output for drift.

# 1. Pin a good node (grab its id from the dashboard or forkmind_recent)
forkmind regression pin a1b2c3d4e5f6 \
  --name octopus-fact \
  --contains "hearts" \
  --regex "blue|copper" \
  --min-similarity 0.5

# 2. List / remove cases
forkmind regression list
forkmind regression remove octopus-fact

# 3. Re-run after changing prompts/models (exit code 1 if any case fails — CI-ready)
forkmind regression run                 # keyless local (Ollama)
forkmind regression run --key $GROQ_API_KEY --upstream https://api.groq.com/openai

Mechanical checks — free, offline, deterministic

• contains — substrings that must appear
• not-contains — substrings that must NOT appear
• regex — patterns that must match
• min-similarity — Jaccard word-overlap vs the baseline (drift guard; defaults to 0.3 so a wildly different answer fails even without explicit assertions). LLM output is non-deterministic, so prefer assertions over exact match.

None of these read meaning. They answer "does this text still look like that text", not "is this answer still correct". contains and regex are precise proxies — if a required fact disappears, they catch it every time. Similarity is a deliberately cheap alarm: it flags that something changed, and it will cry wolf on a rewrite that's perfectly correct.