# tabnas (remote · mcp.tabnas.dev)

Seven tools over the tabnas parsing engine: parse, validate, diagnose, fixtures, compare.

- Trust score: 74/100 (medium)
- Change this week: 0
- Registry status: active
- Liveness: live
- Owner verified: no
- Last scored: 2026-09-25

## Components

- remote · `mcp.tabnas.dev`: 74/100 (this document), [markdown](https://verifymcp.io/servers/dev-tabnas-mcp/mcp.md), [page](https://verifymcp.io/servers/dev-tabnas-mcp/mcp)
- npm · `@tabnas/mcp`: 49/100, [markdown](https://verifymcp.io/servers/dev-tabnas-mcp/tabnas-mcp.md), [page](https://verifymcp.io/servers/dev-tabnas-mcp/tabnas-mcp)

## Channel facts

- Endpoint: `https://mcp.tabnas.dev/mcp`
- Transports: `streamable-http`
- Auth: `none`
- Version: `0.1.16`

## Trust breakdown

How this component scores in each security and reliability category. Every signal is checked automatically against the live server, and we only credit what we can confirm. Scores are 0–100 per category. Scoring method: https://verifymcp.io/docs/scoring (what has changed: https://verifymcp.io/docs/scoring/changelog)

Scored 2026-09-25.

- **Endpoint Security**: 46/100
  - The endpoint's TLS certificate is valid, in date, and uses a strong key.
  - Authorisation not fully verified: no authorisation is required to call this server, and 7 tool(s) never declared a destructiveHint. The MCP spec treats an absent hint as destructive by default, so we cannot call this surface safe.
  - HTTPS enforcement could not be verified: the plaintext port answered with HTTP 405, which proves neither a plaintext path nor enforcement.
  - HSTS check failed: the Strict-Transport-Security header is absent.
  - DNSSEC check failed: this domain isn't protected by DNSSEC.
- **Transport & Reachability**: 100/100
  - Verified streamable-http transport via a live MCP handshake.
- **Schema Quality & AI Usability**: 88/100
  - 100% of prompts and resources have a non-trivial description (not blank, and not just the item's name).
  - AI-judged instruction clarity (excellent).
  - Tool/resource definitions use about 1119 tokens (~93/item across 12 items; 7 tools + 5 resources), lean.
  - Usage-examples check failed: none of the tools include examples.
- **Stability & Change Management**: 100/100
  - No destabilizing schema changes in the last 30 days.
- **Tool Coverage**: 98/100
  - 100% of tools have a non-trivial description (not blank, and not just the tool's name).
  - 93% of tool parameters carry a description.
- **Tool Safety**: 100/100
  - No prompt-injection markers were found in the server instructions, tool names or descriptions we captured.
  - We read all 7 captured tool definition(s), and no name or description among them implies an irreversible operation.
  - An AI judge read all 8 captured unit(s) of tool text and found none that tries to manipulate the model reading it.
- **Capabilities**: 60/100
  - Spec-recency check failed: implements MCP spec 2025-06-18; the latest is 2026-07-28.

## Install

### How do I install the tabnas MCP server?

tabnas is a hosted endpoint at https://mcp.tabnas.dev/mcp, so there is nothing to install locally. Ready-made configuration for Claude, Cursor, VS Code, Codex and 5 more is on this page, copied from each client's own documentation.

### Claude

```bash
claude mcp add --transport http dev-tabnas-mcp 'https://mcp.tabnas.dev/mcp'
```

### Cursor

```json
{
  "mcpServers": {
    "dev-tabnas-mcp": {
      "url": "https://mcp.tabnas.dev/mcp"
    }
  }
}
```

### VS Code

```json
{
  "servers": {
    "dev-tabnas-mcp": {
      "type": "http",
      "url": "https://mcp.tabnas.dev/mcp"
    }
  }
}
```

### Codex

```toml
[mcp_servers.dev-tabnas-mcp]
url = "https://mcp.tabnas.dev/mcp"
```

### opencode

```json
{
  "$schema": "https://opencode.ai/config.json",
  "mcp": {
    "dev-tabnas-mcp": {
      "type": "remote",
      "url": "https://mcp.tabnas.dev/mcp",
      "enabled": true
    }
  }
}
```

### OpenClaw

```bash
openclaw mcp add dev-tabnas-mcp --url 'https://mcp.tabnas.dev/mcp' --transport streamable-http
```

### Hermes

```yaml
mcp_servers:
  dev-tabnas-mcp:
    url: "https://mcp.tabnas.dev/mcp"
```

### Netclaw

```json
{
  "McpServers": {
    "dev-tabnas-mcp": {
      "Transport": "http",
      "Url": "https://mcp.tabnas.dev/mcp"
    }
  }
}
```

### Vellum

```bash
assistant mcp add dev-tabnas-mcp -t streamable-http -u 'https://mcp.tabnas.dev/mcp'
```

### Other

```json
{
  "mcpServers": {
    "dev-tabnas-mcp": {
      "type": "http",
      "url": "https://mcp.tabnas.dev/mcp"
    }
  }
}
```

The mcpServers block is a cross-client convention. Remote transports vary, so check your client's docs.

## Changelog

Every change recorded for this component, newest first. Days that predate change tracking, or that we cannot explain, say so: "we were watching and nothing happened" and "we were not watching" are different claims.

### 2026-09-25 (score 74, 0)

- [functional] We updated how we score, so this day's move reflects our rubric, not a change to the server

### 2026-09-24 (score 74, 0)

- [functional] Server version: 0.1.15 → 0.1.16

### 2026-09-19 (score 74, 0)

- [security] Stability: 0.97 → pass

### 2026-09-17 (score 74, +1)

No change was recorded against any check on this day. Stability & Change Management went from 90 to 93. That category is still filling its 30-day observation window: 27 days of observed history at the previous scan, 28 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-09-15 (score 73, +1)

No change was recorded against any check on this day. Stability & Change Management went from 83 to 87. That category is still filling its 30-day observation window: 25 days of observed history at the previous scan, 26 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-09-13 (score 72, +1)

No change was recorded against any check on this day. Stability & Change Management went from 77 to 80. That category is still filling its 30-day observation window: 23 days of observed history at the previous scan, 24 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-09-11 (score 71, +1)

No change was recorded against any check on this day. Stability & Change Management went from 70 to 73. That category is still filling its 30-day observation window: 21 days of observed history at the previous scan, 22 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-09-09 (score 70, +1)

No change was recorded against any check on this day. Stability & Change Management went from 63 to 67. That category is still filling its 30-day observation window: 19 days of observed history at the previous scan, 20 at this one. The score rises as the window fills, whether or not the server changes.

## MCP tools (7)

### `parse` (~174 tokens)

Parse input with the tabnas engine. Returns {ok:true, tree} or, on parse failure, {ok:false, diagnostic} — the structured diagnostic described by resource tabnas://schema/diagnostic. An invalid grammar is rejected as {ok:false, errors:[{path,message}]}. Without a grammar the bare engine is used, which defines no rules and produces an undefined tree for every input.

Input parameters:

- `grammar` (object): Serialized GrammarSpec (pure JSON, no functions). Schema: resource tabnas://schema/grammar. Grammars are validated before use; a `ref` key or a non-builtin function reference is rejected.
- `input` (string, required): Source text to parse.
- `options` (object): TabnasOptions applied to the fresh instance before the grammar. Data only: a plugins entry is rejected.

### `validate_grammar` (~188 tokens)

Validate a serialized GrammarSpec. Structural validation against the bundled grammar schema, an engine load in a fresh instance, and a check that every rule reference (`p`, `r`) names a rule the grammar actually defines — a dangling reference loads cleanly and then fails at parse time with `unknown_rule`. Returns {ok:true, v} (v = declared builtin config-schema version, absent means 1) or {ok:false, errors:[{path,message}]}. Security: a grammar carrying a `ref` key, or any function reference that is not a $-suffixed engine builtin, is rejected — validating a grammar never runs supplied code.

Input parameters:

- `grammar` (object, required): Serialized GrammarSpec (pure JSON, no functions). Schema: resource tabnas://schema/grammar. Grammars are validated before use; a `ref` key or a non-builtin function reference is rejected.

### `explain_parse_error` (~140 tokens)

Parse input and explain the failure. Returns {failed:false} when the input parses; otherwise {failed:true, diagnostic, registry} where registry is the error-code registry entry {code,message,hint} for the diagnostic code (resource tabnas://errors), or null for a code the bundled registry does not know (e.g. a plugin-declared code).

Input parameters:

- `grammar` (object): Serialized GrammarSpec (pure JSON, no functions). Schema: resource tabnas://schema/grammar. Grammars are validated before use; a `ref` key or a non-builtin function reference is rejected.
- `input` (string, required): Source text to parse.

### `test_grammar` (~155 tokens)

Run TSV fixture content against a grammar in a fresh instance, using the fleet fixture convention (@tabnas/support): line 1 is a header, the input column is escape-decoded, the expected column is JSON or ERROR / ERROR:<code>. Returns {pass, fail, rows:[{row,input,expected,got,ok}]}. Refuses more than 10000 rows.

Input parameters:

- `grammar` (object): Serialized GrammarSpec (pure JSON, no functions). Schema: resource tabnas://schema/grammar. Grammars are validated before use; a `ref` key or a non-builtin function reference is rejected.
- `options` (object)
- `spec` (string, required): TSV fixture content (not a path).

### `list_plugins` (~36 tokens)

List every bundled tabnas plugin descriptor (tabnas.plugin.json of each fleet repo), sorted by name. Returns {plugins:[...]}.

### `describe_plugin` (~55 tokens)

The full descriptor for one plugin, by package name ('@tabnas/csv') or bare fleet name ('csv'). Unknown names get {ok:false, errors} naming the known plugins.

Input parameters:

- `name` (string, required): Plugin name.

### `compare_grammars` (~220 tokens)

Grammar compatibility (AX plan Phase 5): does candidate grammar B still accept what baseline A accepted, and does it build the same tree for inputs both accept? Returns EVIDENCE AND CONFIDENCE, never a bare verdict: {normalForm, proven[], observed[], changes[], counterexamples[], confidence, why}. confidence:'low' with a stated reason is a successful run, not a failure — language inclusion is undecidable in general, so anything outside the decidable subset is reported not-proven rather than incompatible. Supply `corpus` (real inputs) for the tier that measures what your documents actually do.

Input parameters:

- `a` (object, required): Baseline grammar: the serialized GrammarSpec already deployed.
- `b` (object, required): Candidate grammar: the serialized GrammarSpec proposed to replace it.
- `corpus` (array): Inputs to replay through both grammars, comparing acceptance and tree shape.
- `depth` (integer): Derivation depth for generated inputs (default 3).
- `options` (object): TabnasOptions applied to both instances.

## Diagnostics

Captured diagnostic sections: TLS, DNSSEC, Authorisation, Transports. The full working is on the page: https://verifymcp.io/servers/dev-tabnas-mcp/mcp#diagnostics

## Score history

- 2026-09-25: 74
- 2026-09-24: 74
- 2026-09-23: 74
- 2026-09-22: 74
- 2026-09-21: 74
- 2026-09-20: 74
- 2026-09-19: 74
- 2026-09-18: 74
- 2026-09-17: 74
- 2026-09-16: 73
- 2026-09-15: 73
- 2026-09-14: 72
- 2026-09-13: 72
- 2026-09-12: 71
- 2026-09-11: 71
- 2026-09-10: 70
- 2026-09-09: 70
- 2026-09-08: 69
- 2026-09-07: 69
- 2026-09-06: 68
- 2026-09-05: 68
- 2026-09-04: 67
- 2026-09-03: 67
- 2026-09-02: 67
- 2026-09-01: 66
- 2026-08-31: 66
- 2026-08-30: 65
- 2026-08-29: 65
- 2026-08-28: 64
- 2026-08-27: 64

## Common questions

### What is the tabnas MCP server?

tabnas is an MCP server listed in the public MCP registry as dev.tabnas/mcp. Seven tools over the tabnas parsing engine: parse, validate, diagnose, fixtures, compare. This page covers its hosted endpoint (https://mcp.tabnas.dev/mcp).

### Is the tabnas MCP server safe to use?

tabnas scores 74 out of 100 on VerifyMCP. That is a record of what we were able to check automatically, not an endorsement. The category breakdown on this page shows every signal behind the number, including the ones we could not confirm.

### What tools does the tabnas MCP server expose?

tabnas exposes 7 tools: parse, validate_grammar, explain_parse_error, test_grammar, list_plugins, and 2 more. Their descriptions and schemas cost roughly 968 tokens of context every time the server is loaded.

### Does the tabnas MCP server require authentication?

No. We connected to tabnas without credentials and it answered, so anything it exposes is reachable by anyone who knows the address.

### Is the tabnas MCP server still maintained?

tabnas is still listed as active in the MCP registry. We last reached this channel on 25 September 2026. Those dates come from our own scans of the registry and the channel itself, not from anything the publisher announced.

## Links

- Remote endpoint: https://mcp.tabnas.dev/mcp
- Repository: https://github.com/tabnas/mcp
- Website: https://tabnas.dev/mcp
- Changelog RSS feed: https://verifymcp.io/servers/dev-tabnas-mcp/mcp.xml
- Changelog JSON feed: https://verifymcp.io/servers/dev-tabnas-mcp/mcp.json
- HTML version of this page: https://verifymcp.io/servers/dev-tabnas-mcp/mcp