Jev MCP Server
PYPI · JEV-MCP-SERVER
MCP server for Jev (TypeSafe System One): typed decisions with calibrated probabilities.
Available components
Last scanned (23 minutes ago)
Scores higher than 62% of PyPI servers
Category AI and Machine Learning
How this component scores in each security and reliability category. Every signal is checked automatically from public evidence about the published package, including repeated runs of it in an isolated sandbox, and we only credit what we can confirm. How we score → Why this is hard to score →
Supply Chain Security50
- Malware scan not yet available for this package.Unverified
- No known CVEs affecting this package version or its production dependencies.Pass
- Runs hatchling.build at install time, a recognised build step with no custom scripting around it. View diagnostics → Pass
- 0 of 28 dependencies flagged as unhealthy. View diagnostics → Pass
Provenance & Transparency19
- Repository check failed: no source repository is declared. See how to fix → View diagnostics → Fail
- Provenance check failed: no build-provenance attestation is published. See how to fix → View diagnostics → Fail
- Clear OSI-approved license (MIT).Pass
- Actively maintained (last published 25 days ago).Pass
- Disclosure check failed: no security disclosure policy was found in the source repository. See how to fix → Fail
Schema Quality & AI Usability57
- AI-judged instruction clarity (good).Pass
- Context-footprint check failed: tool/resource definitions use about 1326 tokens (~189/item across 7 items; 7 tools + 0 resources), over budget; trim descriptions and params. See how to fix → Fail
- Usage-examples check failed: none of the tools include examples. See how to fix → Fail
Stability & Change Management87
- Stability observed for 26 of 30 days with no destabilising changes; credit accrues until the full window elapses.Partial
Tool Coverage71
- 100% of tools have a non-trivial description (not blank, and not just the tool's name).Pass
- 0% of tool parameters carry a description.Fail
- Structured output schemas are declared (100% of tools); any adoption earns full credit.Pass
Tool Safety100
- No prompt-injection markers were found in the server instructions, tool names or descriptions we captured.Pass
- We read all 7 captured tool definition(s), and no name or description among them implies an irreversible operation.Pass
- An AI judge read all 7 captured unit(s) of tool text and found none that tries to manipulate the model reading it.Pass
Capabilities100
- Implements a supported MCP spec version (2025-11-25); the latest is 2026-07-28.Pass
Every change we have recorded for this component, newest first. Security-relevant changes are always shown. ▲ marks a change for the better, ▼ a change for the worse; unmarked changes are neutral.
- 18 Oct 26 +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.
- 15 Oct 26 +37
- Injection markers: unverified → pass ▲ security
- Tool coverage: unverified → 100 ▲ functional
- Stability: unverified → 0.77 ▲ functional
- MCP protocol: unverified → pass ▲ functional
- 13 Oct 26 −15
- Malware scan: pass → unverified ▼ security
- 12 Oct 26 −16
- Tool safety: pass → unverified ▼ security
- Stability: 0.40 → unverified ▼ security
- Malware scan: unverified → pass ▲ security
- Tool coverage: 100 → unverified ▼ functional
- Capabilities: pass → unverified ▼ functional
- First check of Schema quality: unverified functional
- 3 Oct 26 +1
No change was recorded against any check on this day. Stability & Change Management went from 33 to 37. That category is still filling its 30-day observation window: 10 days of observed history at the previous scan, 11 at this one. The score rises as the window fills, whether or not the server changes.
- 30 Sept 26 +4
- Stability: unverified → 0.27 ▲ functional
- 29 Sept 26 0
- Provenance: unverified → fail ▼ security
- 28 Sept 26 −15
- We updated how we score, so this day's move reflects our rubric, not a change to the server See what changed → functional
Diagnostic detail from the automated scan of this channel: what the scanner observed at each step, so you can see exactly where a check passed or failed. It is informational only and never changes the trust score.
Captured 18 Oct 2026 · Analysed pypi/jev-mcp-server@0.2.2
Provenance No attestation
The registry publishes no build provenance for this version, so there is nothing to verify.
| Result | No attestation |
|---|---|
| Ecosystem | pypi |
| Reason | No attestation published |
Background: How many MCP packages publish verified provenance →
Install scripts 1 script
| Hook | Tier | Command |
|---|---|---|
| build_backend | allowlisted | hatchling.build |
Background: Why install scripts are a supply-chain risk →
Dependencies 28 packages
| Packages resolved | 28 |
|---|---|
| Tree resolution | Complete |
Background: SBOMs and build attestations, explained →
The tools this component advertises to a client, with an estimated token cost for each. Expand a tool to see its parameters and schema. The per-tool counts are indicative and are not scored directly; the schema's total context footprint is one signal in Schema Quality & AI Usability. A tool's description is untrusted text the model reads on every call, which is what makes this list a security surface and not just an inventory: how tool poisoning works →
choice ~206
Ask Jev (TypeSafe System One) to pick ONE of 2-100 mutually exclusive options, with calibrated probabilities. The official `choice` question type — for fast, cheap structured decisions: triage, routing, classification, prioritization, tie-breaking among enumerated candidates. Returns probabilities over ALL options (not just the winner), so near-ties are visible. NOT for open-ended generation or multi-step reasoning — use an LLM for those. Args: question: The decision, e.g. "Which error class is most likely the root cause?" options: Mapping of short unique id -> one-line description. 2-100 options. context: Optional background facts that inform the decision. Keep it short. Returns: JSON string: {choice, confidence, probabilities (sorted desc), runner_up, model, latency_ms, usage}
| Name | Type | Req | Description |
|---|---|---|---|
| context | string | – | – |
| options | object | yes | – |
| question | string | yes | – |
| Name | Type | Req | Description |
|---|---|---|---|
| result | string | yes | – |
No examples provided.
classify ~213
Batch-classify up to 100 items against ONE shared set of categories using Jev. Runs the official `choice` question type once per item and aggregates the results — routing support tickets, labeling log lines, triaging inbox items against your own label set. Much cheaper and faster than an LLM for mechanical labeling. Args: items: 1-100 non-empty strings to classify. options: Mapping of short unique id -> one-line category description. 2-100 options. question: Per-item question; the item itself is appended automatically. context: Optional background facts shared by all items. Returns: JSON string: {results: [{item, choice, confidence, probabilities}], summary (counts per choice, sorted desc), model, total_latency_ms, usage: {input_tokens, output_tokens, calls, cached_calls}}
| Name | Type | Req | Description |
|---|---|---|---|
| context | string | – | – |
| items | array | yes | – |
| options | object | yes | – |
| question | string | – | – |
| Name | Type | Req | Description |
|---|---|---|---|
| result | string | yes | – |
No examples provided.
compare ~207
Ask Jev (TypeSafe System One) which of two candidates — a or b — better satisfies the question. The official `choice` type as a focused A/B judgment: "which error message is clearer?", "which rollout plan fits this service better?", "title A or B?". Returns the preferred side PLUS the probability split, so a 52/48 coin flip is visible instead of hidden. Args: question: What to judge, phrased so one side can win, e.g. "Which error message is clearer?" a: Candidate A text. b: Candidate B text. context: Optional background facts. Keep it short. Returns: JSON string: {preferred: "a"|"b", confidence, probabilities: {a, b}, runner_up, model, latency_ms, usage}
| Name | Type | Req | Description |
|---|---|---|---|
| a | string | yes | – |
| b | string | yes | – |
| context | string | – | – |
| question | string | yes | – |
| Name | Type | Req | Description |
|---|---|---|---|
| result | string | yes | – |
No examples provided.
noul ~166
Ask Jev (TypeSafe System One) a yes/no question; returns a 0-1 degree (>= 0.5 leans yes). The official `noul` question type — fast, cheap binary checks: "is this change breaking?", "does this log line match the reported symptom?". No probability list, just the degree. NOT for questions that need multi-step reasoning — use an LLM for those. Args: question: A yes/no question, e.g. "Is renaming a public config key a breaking change?" context: Optional background facts. Keep it short. Returns: JSON string: {noul, verdict, model, latency_ms, usage}
| Name | Type | Req | Description |
|---|---|---|---|
| context | string | – | – |
| question | string | yes | – |
| Name | Type | Req | Description |
|---|---|---|---|
| result | string | yes | – |
No examples provided.
score ~203
Ask Jev (TypeSafe System One) to grade something on an ORDERED scale of 2-8 levels. The official `score` question type — risk/severity/quality rubrics, e.g. levels ["minor", "moderate", "severe", "critical"]. Returns a fractional 0-based index into `levels` (1.88 = between levels[1] and levels[2], leaning to levels[2]), plus confidence and per-level probabilities. Args: question: What to grade, e.g. "Regression risk of renaming public config key X". levels: 2-8 unique ordered scale points, low to high. context: Optional background facts. Keep it short. Returns: JSON string: {score, nearest_level, confidence, probabilities (sorted desc), model, latency_ms, usage}
| Name | Type | Req | Description |
|---|---|---|---|
| context | string | – | – |
| levels | array | yes | – |
| question | string | yes | – |
| Name | Type | Req | Description |
|---|---|---|---|
| result | string | yes | – |
No examples provided.
setup ~151
One-time onboarding: verify a TypeSafe API key with a live call, then store it locally. Use when TYPESAFE_API_KEY is not set in the server environment: pass your key once (get one at https://console.typesafe.ai/settings/keys). It is verified against the live API, then saved to ~/.config/jev-mcp/key (permissions 0600) and never echoed back. An existing TYPESAFE_API_KEY env var always takes precedence over the stored file. Args: api_key: Your TypeSafe API key (from console.typesafe.ai/settings/keys). Returns: JSON string: {ok, stored_path, verified}
| Name | Type | Req | Description |
|---|---|---|---|
| api_key | string | yes | – |
| Name | Type | Req | Description |
|---|---|---|---|
| result | string | yes | – |
No examples provided.
verify ~180
Check ONE claim against supplied evidence; returns a 0-1 support degree (>= 0.5 leans supported). The official `noul` type framed as claim-vs-evidence: fact-check a report line against its source, confirm a log excerpt actually shows the reported symptom, validate a summary against the document it summarizes. Evidence is passed as context — Jev judges only what it is given, never invents evidence. Args: claim: A single falsifiable claim, e.g. "The 404s come from edhub, not the gateway". evidence: The evidence text to check the claim against (log excerpt, doc paragraph, diff). Returns: JSON string: {noul, verdict, model, latency_ms, usage}
| Name | Type | Req | Description |
|---|---|---|---|
| claim | string | yes | – |
| evidence | string | yes | – |
| Name | Type | Req | Description |
|---|---|---|---|
| result | string | yes | – |
No examples provided.
How do I install the Jev MCP Server server?
Jev MCP Server runs locally as a PyPI package, launched with uvx jev-mcp-server. Ready-made configuration for Claude, Cursor, VS Code, Codex and 5 more is on this page, copied from each client's own documentation.
pypi · jev-mcp-server
claude mcp add wangkuangkuang-jev-mcp-server -- uvx jev-mcp-server
What is the Jev MCP Server server?
Jev MCP Server is listed in the public MCP registry as io.github.wangkuangkuang/jev-mcp-server. MCP server for Jev (TypeSafe System One): typed decisions with calibrated probabilities. This page covers its PyPI package (jev-mcp-server).
Is the Jev MCP Server server safe to use?
Jev MCP Server scores 57 out of 100 on VerifyMCP. We found no known CVEs affecting it as of 18 October 2026. 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 Jev MCP Server server expose?
Jev MCP Server exposes 7 tools: choice, score, noul, compare, verify, and 2 more. Their descriptions and schemas cost roughly 1,326 tokens of context every time the server is loaded.
Is the Jev MCP Server server still maintained?
Jev MCP Server is still listed as active in the MCP registry. We last reached this channel on 18 October 2026. Those dates come from our own scans of the registry and the channel itself, not from anything the publisher announced.
What licence is the Jev MCP Server server under?
Jev MCP Server declares the MIT licence, which is OSI-approved. That covers the source only, and says nothing about the cost of any service it calls.