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PopNx MCPMCP servers for people who use AI · explained in plain words

TestGraph

by BBCBasicversion 0.1.1i★ –iRuns in the cloud
Registry nameio.github.BBCBasic/testgraph

Install

Overview

Description from the maker (original English)

Shared semantic graph for AI reviews, classification and structured memory across AI assistants.

PopNx MCP’s three pillars

These three are never merged into one score: opinions, measurements and popularity are different things.

What you can do with it

We have not written a plain-language summary for this one yet. Below are the facts we read from the registry.

  • Connection: Runs in the cloud
  • Transport: Streamable HTTP
  • Category: Search & AI memory

Install

Pick the AI app you use, then copy the settings.

Before you install

  • Basic checks: 1 of 1 passed
  • Runs on the maker’s server: what you ask it goes through their server.
  • The registry lists no key to fill in.

You need

Which app do you use?

Pick your app above. We remember it, so next time the button says “Install in …”.

Works in Claude on the web, desktop and mobile:

  1. Open Settings → Connectors
  2. Press Add custom connector
  3. Paste the address below and press Add
  4. If it asks you to sign in, sign in with the maker
SettingsConnectors1+ Add2https://…3
https://testgraph.21dle.co.uk/mcp-v2

Run this in your terminal

claude mcp add --transport http testgraph https://testgraph.21dle.co.uk/mcp-v2

Open in Cursor

Or copy the settings yourself

Paste into .cursor/mcp.json in your project, or ~/.cursor/mcp.json

{
  "mcpServers": {
    "testgraph": {
      "url": "https://testgraph.21dle.co.uk/mcp-v2"
    }
  }
}

Your browser asks to open the app, then the app shows the settings and asks you to confirm. Key values are left empty for you to fill in.

Open in VS Code

Or copy the settings yourself

Paste into .vscode/mcp.json in your project

{
  "servers": {
    "testgraph": {
      "type": "http",
      "url": "https://testgraph.21dle.co.uk/mcp-v2"
    }
  }
}

Your browser asks to open the app, then the app shows the settings and asks you to confirm. Key values are left empty for you to fill in.

ChatGPT connects only to servers on the internet:

  1. Open ChatGPT on the web → Settings → Connectors (Apps)
  2. Press Create or Add (some plans need Developer mode under Advanced first)
  3. Paste the address below, give it a name and save
  4. If it asks you to sign in, sign in with the maker
SettingsConnectors1+ Create2https://…3
https://testgraph.21dle.co.uk/mcp-v2

Menu names can differ slightly by plan and over time.

Your choice stays on this device in a cookie; no account needed.

These settings are generated from the maker’s registry entry. If the README says otherwise, follow the README.

What it can do

We have not read this server’s tool list yet; we check endpoints in rotation.

Basic checksi

We check information anyone can see; we have not read the code. Checks that do not apply are left out of the count. · Checked Nov 6, 2026

  • ✓ Pass

    Maker matches the repo

    The registry name was verified with the GitHub account BBCBasic, which owns the repo

  • … Not checked yet

    Still maintained

    We have not read this repo from GitHub yet

  • … Not checked yet

    Has a licence

    We have not read this repo from GitHub yet

  • … Not checked yet

    Endpoint responds

    Not checked yet; we check endpoints in rotation

  • … Not checked yet

    Sign-in with OAuth

    Not checked yet; we check endpoints in rotation

  • … Not checked yet

    No hidden instructions in tool descriptions

    Not checked yet; we read the tool list when we check the endpoint

Compared with others in Search & AI memoryi

  • More stars than 0% of the other 7208 servers in this category
  • Published to the registry more recently than 33% of the other 7208 servers in this category
  • Basic checks equal to or better than 100% of the other 7208 servers in this category

Compared with every active server in this category in the registry. Stars count only when the publisher owns the repo.

Common questions

Is TestGraph safe?

It passed 1 of 1 applicable basic checks. We have not read the code. Before adding a key or token, see what access the server asks for and use a key with only the permissions you need.

What keys or codes does it need?

The registry does not list a required key, though some servers ask you to sign in on first use.

Does it run on my computer or in the cloud?

It runs in the maker’s cloud. Connect over the internet with nothing to install, but what you send passes through the maker’s servers.

Is it still maintained?

The GitHub repo last changed –, and the latest version (0.1.1) reached the registry 2 months ago.

Which apps can use it?

Apps that support MCP, such as Claude Desktop, Claude Code, Cursor and VS Code. It connects by URL, so apps that accept remote MCP servers work too, such as ChatGPT in developer mode.

What can I use instead?

In the same category: Context7, Codebase Memory, Exa

Alternatives

Servers in the same category from other makers, sorted by stars.

Reading a card:★ GitHub starsiThree pillars: reviews · checks · usageiUpdated = latest version published to the registryi

Context7

by upstash

Feeds AI the latest docs for libraries and frameworks before it answers, so code it writes does not use outdated, removed functions.

Computer or cloud★ 64,224MITUpdated 3 days ago
Install

Codebase Memory

by DeusData

Codebase knowledge graph for AI agents — 162 languages, sub-ms queries, 99% fewer tokens.

Runs on your computer★ 48,148MITUpdated 19 days ago
Install

Exa

by exa-labs

Connect AI agents to Exa for web search, content fetching, and multi-step research.

Runs in the cloud★ 5,213MITUpdated 44 days ago
Install

README from the maker

Open the README

Copied from the maker’s repo as written. PopNx MCP has not reviewed or endorsed it. HTML, images and scripts are removed. Links lead off this site.

TestGraph

Can independent AIs build shared knowledge without silently overwriting each other?

TestGraph is an experimental shared knowledge and experience graph for AI assistants. It lets independent AI clients contribute to the same graph while preserving the original human evidence, model attribution, disagreement, confidence and the path by which a conclusion was reached.

Status: working pre-release research system. TestGraph has been exercised through MCP with multiple AI clients, including cross-model classification, retrieval, assessment and deliberation. It is not yet presented as a stable production service or API.

The central question is not simply whether an AI can remember something. It is:

Can multiple independent AIs accumulate reusable knowledge, disagree without destroying each other's conclusions, and eventually reach justified convergence with an audit trail of why?

The experiment

A human observation can be interpreted independently by different AI systems:

Human evidence

| +---- AI A ---- "ferry belongs_to transportation" | +---- AI B ---- "ferry belongs_to public transport" | v TestGraph +-------------+ | evidence | | provenance | | confidence | | disagreement| | votes | | resolution | +------+------+ | v reusable shared knowledge

TestGraph does not require those models to use identical words before their work can be useful. A naming disagreement can remain a naming disagreement. A substantive semantic disagreement can remain unresolved and attributable until evidence or an explicit resolution justifies convergence.

The server stores and verifies the process; the calling AI supplies the open-ended semantic reasoning.

In the experimental typed-classification mode, the is_a graph has one reserved synthetic root, .. It gives every semantic branch a common structural origin without making entity or another model-chosen term globally privileged. Classifiers traverse outward from . progressively; they never use it as an ordinary subject type.

You can keep enriching a subject you own, or one attached to your own non-deleted review, while its classification awaits independent review or dispute resolution. This follows your authenticated TestGraph user identity across AI clients. Enrichment preserves the pending classification and its audit trail; it does not count as an independent classification decision. Other contributors must settle an unconfirmed subject's classification before updating it through the MCP mutation tools. Evidence, conflict-preservation and other write validations still apply.

What TestGraph is investigating

  1. Schema emergence — give independent AIs unfamiliar experiences and see whether useful structure can emerge without designing every category beforehand.
  2. Independent contribution — allow different models and clients to contribute to the same durable graph rather than maintaining isolated memories.
  3. Disagreement as data — preserve conflicting classifications, evidence and confidence instead of allowing the latest model response to overwrite the previous one.
  4. Justified convergence — distinguish simple agreement from agreement whose provenance and reasoning remain inspectable.
  5. Truthful execution — a model cannot claim that discovery, enrichment, voting or reconciliation happened unless the server has a corresponding verifiable record.
  6. Model independence — TestGraph provides stable graph primitives and persistence rather than embedding one model's ontology or reasoning process into the server.

These are architecture and test goals, not merely prompting instructions.

How this differs from adjacent systems

Area / systemPrimary concernTestGraph's experimental focus
Agent memory systems such as Mem0Remembering useful information for an agent/userShared epistemic state contributed to by independent AI clients
Stateful agent systems such as LettaPersistent agent context and memoryExternal evidence, attribution, disagreement and cross-model reuse
Temporal knowledge graphs such as GraphitiEvolving structured knowledge for agentsIndependent contributors plus explicit disagreement, deliberation and convergence
Model Context Protocol (MCP)Interoperability between AI clients and tools/dataA stateful knowledge layer reached through MCP; TestGraph is not a replacement for MCP
Multi-agent frameworksCoordinating agents to complete tasksDurable knowledge that survives individual conversations/agents and records how conclusions were reached

This comparison is about architectural emphasis, not a claim that TestGraph replaces or outperforms those projects.

Identity and capability keys

TestGraph supports two ways to have an identity.

1. Persistent Google-backed identity — optional

Open:

https://testgraph.21dle.co.uk/account

Sign in with Google. TestGraph creates or recovers the same internal TestGraph user_id each time you return with that Google identity.

From that account you can create as many tg_... capability keys as you need for ChatGPT, Claude, another MCP client or disposable testing.

Google account

| v persistent TestGraph user_id | +---- tg_ key A ---- ChatGPT +---- tg_ key B ---- Claude +---- tg_ key C ---- test client

Capability keys are stored hashed, not in recoverable plaintext. A newly generated tg_ key is shown once. If you want to reuse it later, store it yourself. If you lose it, sign back in with Google and create another key; the underlying TestGraph identity and data remain unchanged.

Google is therefore an optional persistent identity/recovery mechanism, not a requirement for using TestGraph.

2. Standalone capability — no Google account required

Open:

https://testgraph.21dle.co.uk/capability/new

This creates a new standalone TestGraph identity and a private tg_... capability URL exactly as before. Keep it safe: without an external identity attached, possession of that capability is what gives access to that TestGraph identity.

Connecting an AI through MCP

The current remote MCP endpoint is:

https://testgraph.21dle.co.uk/mcp-v2

Use the website versions of ChatGPT or Claude when setting up the connector.

The normal OAuth connection flow is now:

AI client starts OAuth

| v TestGraph /account | +---- Sign in with Google | | | v | persistent TestGraph identity | +---- Use existing tg_ capability | v existing identity | v Confirm "Connect this AI" | v OAuth completes and client receives scoped tokens

The AI client receives OAuth access/refresh tokens. It does not receive your Google credentials or your private TestGraph capability key.

ChatGPT
  1. Open ChatGPT on the web.
  2. Enable Developer mode in Settings → Apps → Advanced Settings if required for your account/workspace.
  3. Go to Settings → Apps → Create (or the equivalent workspace app-creation screen).
  4. Enter https://testgraph.21dle.co.uk/mcp-v2 as the MCP endpoint.
  5. Choose OAuth authentication.
  6. TestGraph opens its account page. Sign in with Google or choose the existing-capability route.
  7. Confirm Connect this AI.
  8. Complete app creation and start a new chat with TestGraph enabled.
Claude
  1. Open Claude on the web.
  2. Go to Customize → Connectors.
  3. Choose Add custom connector.
  4. Enter https://testgraph.21dle.co.uk/mcp-v2.
  5. Complete OAuth when prompted.
  6. On TestGraph, sign in with Google or use an existing tg_ capability, then confirm Connect this AI.
  7. Enable the connector in a conversation.

Why provenance matters

Convergence alone is weak evidence. TestGraph is interested in justified convergence: retaining enough information to answer which human evidence started a conclusion, which model proposed it, whether another model independently agreed, whether disagreement was naming or semantic, what supported a vote or counterproposal, and how a resolution was reached.

Current multi-model work

Current workflows include:

  • storing human reviews/experiences with provenance;
  • independent subject classification and enrichment;
  • discovering and proposing new vocabulary;
  • retrieving structure created by another AI;
  • model-attributed assessments;
  • deliberations, proposals, critiques and votes;
  • server-recorded resolutions;
  • server-verifiable acceptance criteria;
  • version-aware MCP writes so a stale client cannot silently write against a different deployment;
  • optional persistent TestGraph identities with independently revocable capability credentials.

This is ongoing experimental work. The repository deliberately does not claim that cross-model semantic convergence has been solved.

A simple example

Classification is metadata rather than a storage address. A review of a ferry can remain a ferry review while the graph records:

ferry --belongs_to--> transportation

Another AI may propose a more specific or differently named relationship. TestGraph can retain both contributions and their provenance while the disagreement is examined.

Progressive vocabulary traversal

Normal AI workflows do not download the complete classification vocabulary. They first try resolve_subject_type for a direct canonical-name or alias match. If more exploration is needed, they use:

  • list_root_subject_types to inspect the top-level choices;
  • list_child_subject_types to inspect one level of a promising branch;
  • get_subject_type_path to verify the active parent path of a known type.

At each level the AI ranks a small candidate list, follows the strongest branch and retains the others as fallbacks. An inadequate classification or empty scoped retrieval causes it to backtrack rather than declare a global miss. Traversal stops at the most specific adequate existing type, or after enough bounded evidence exists to call resolve_subject_hierarchy with the verified ancestors and only the genuinely missing nodes.

The existing search tool can then search the selected type and its descendants without returning those taxonomy nodes to the model. vocabulary_index remains available as a complete administrative/debugging export, not as a prerequisite for saving or retrieval.

Equivalent REST navigation endpoints are available under /api/v2/subject-types/roots, /api/v2/subject-types/{id}/children and /api/v2/subject-types/{id}/path.

MCP deployment/version safety

Cross-client testing exposed a practical problem: an AI client can retain an older MCP tool definition after the server has changed. TestGraph exposes server/deployment information and requires a live deployment token immediately before protected write operations. A stale or mismatched connection is rejected before data is changed.

The user-facing error tells the client to refresh or reconnect TestGraph, without assuming the user named the connector “V2”.

Architecture

Human evidence / experience

| v Independent AI clients (reasoning + discovery) | v MCP/OAuth | v TestGraph server +--------------------+ | stable identities | | graph relationships| | provenance | | assessments | | deliberations | | verification | | audit history | +---------+----------+ |

Only the beginning is shown; read the rest in the repo

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