jevcore MCP
An MCP server giving an agent three Jev tools: typed yes or no, choice and score questions with probabilities, offline by default.
- 105 ★ on the repository
- Last commit
- Apache-2.0
Extended access
Why this level
- In live mode call arguments and evidence go to the external TypeSafe or OpenRouter service, and secret redaction works on a best-effort basis.
Install
- Works in
In your terminal, with SkillFoxx CLI
npx skillfoxx add mcp/jevcoreDetects the agents on your machine, shows the access level and pins the version.
Other ways to install
Access and checks
How we reviewExtended accessThe tool runs code or makes network calls and only reads external data.
- In live mode call arguments and evidence go to the external TypeSafe or OpenRouter service, and secret redaction works on a best-effort basis.
This is third-party code. Review the repository files before installing.
What it does
jevcore connects Jev from TypeSafe to DeepSeek Harness and any MCP client. Jev is not a chat model: it answers typed questions, that is yes or no (`noul`), choice (`choice`) and score (`score`), and returns calibrated probabilities instead of prose. The package gives the agent exactly that surface: the `jev_ask`, `jev_rank` and `jev_check` tools. The repository has three packages: `jevcore` with the decisions themselves, `jevcore-dsh` with the DeepSeek Harness plugin and `jevcore-mcp` with the same three tools over MCP through stdio. By default an offline provider with synthetic answers is connected and no network calls happen. Real answers need a TypeSafe or OpenRouter key. Every transmission is named upfront in one startup line, and two optional gates, safety and context, are off.
Who it is for. DeepSeek Harness and MCP client users who need calibrated decision scores instead of wordy answers.
Good fit when
- The agent needs a yes or no answer with a probability for a specific claim and evidence.
- A list of candidates must be ranked against a query through `jev_rank`.
- You want to test the connection offline without a key or network calls.
- The optional safety gate is enabled and you see in advance which fields will leave.
Not a fit when
- You need a conversational model that writes text: Jev does not write prose.
- You cannot send data to third parties: live mode transmits questions to TypeSafe or OpenRouter.
- You need guaranteed secret hiding: redaction works on a best-effort basis.
Example request
Ask Jev whether this test log supports the claim that all checks passed and return the probability.MCP
- Transport
- stdio
- Authentication
- key is optional
Environment variables
TYPESAFE_API_KEYsecret- TypeSafe key, enables live mode through TypeSafe.
OPENROUTER_API_KEYsecret- OpenRouter key, used when no TypeSafe key is set.
JEV_PROVIDER- Explicit provider choice: mock, live or openrouter.
Limitations
The offline provider is the default and its answers are synthetic. Real scores need `provider: live` and a key, and then call arguments go to TypeSafe or OpenRouter. Redaction before sending removes known fields and recognizable secret shapes, but a secret under an unusual name in free text will pass. If that is unacceptable, do not enable the live provider. The DeepSeek Harness plugin needs Node `^22.19.0` or 24 and newer, while `jevcore` and `jevcore-mcp` run on Node 20 and newer.
How to disable. Remove the `jev` entry from the MCP client configuration or, if installed, remove the DeepSeek Harness plugin with `dsh plugin --profile <profile> remove jevcore-dsh`.
FAQ
How do I connect the server?
Add a stdio server with the `npx -y jevcore-mcp` command to the client. DeepSeek Harness has a plugin: `dsh plugin --profile <profile> add jevcore-dsh`.
Why does the key not reach the server in DeepSeek Harness?
Harness strips names containing KEY, PASSWORD, SECRET or TOKEN from the environment, so the key goes in the `env` block of the configuration, and without it the server stays on the offline provider with no error.
Which providers are supported?
Offline, TypeSafe and OpenRouter. The choice follows the `TYPESAFE_API_KEY` and `OPENROUTER_API_KEY` keys or the `JEV_PROVIDER` variable.
What do the tools do?
`jev_ask` answers a yes or no, choice or score question, `jev_rank` ranks candidates against a query, `jev_check` checks a claim against evidence.
What leaves the machine in live mode?
Call arguments after redaction: for `jev_rank` the query and all candidates, for `jev_check` the claim and evidence. Each transmission is printed at startup as a `SENDS` line.
Discussion
No questions or reviews yet.
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README in short
The TypeScript repository holds three packages, documentation on approval, hosts and limits, a security policy and README translations. The author explains that the project is built to exclude the hidden data transmission seen in other Jev plugins for DSH.