WardrikMCP.Server (wardrik_mcp v0.1.0-rc.1)

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An MCP server and how to reach it.

github: [
  transport: {:stdio, command: "github-mcp-server", args: ["stdio"], env: %{}},
  only: ["search_issues", "create_issue"],
  gated: ["create_*"]
]

linear: [
  transport: {:streamable_http, url: "https://mcp.linear.app/mcp", headers: %{}},
  credential_name: "linear"
]

Options

  • :transport - required. {:stdio, command: ..., args: ..., env: ...} or {:streamable_http, url: ..., headers: ...}. The url is the server's endpoint, as it publishes it, as "https://mcp.linear.app/mcp". A command gets its env and only these of the app's own variables: HOME, LANG, LC_ALL, LOGNAME, PATH, SHELL, TERM, TMPDIR and USER. It's started through env, which unsets the rest.
  • :only - the server's tool names to offer, as ["search_issues"]. Every tool unless set.
  • :except - the server's tool names to leave out.
  • :prefix - the prefix for tool names, as "linear" for linear__search_issues. The server's name unless set.
  • :credential_name - the credential each principal reaches the server with. See WardrikCore.Credentials.
  • :credential_header - the HTTP header the credential goes in. "authorization" unless set.
  • :credential_scheme - the scheme before the credential. "Bearer" unless set.
  • :credential_env - the environment variable the credential goes in, for a command.
  • :timeout - milliseconds a call may take. 60_000 unless set.
  • :max_result_bytes - bytes of a result the model gets. 131_072 unless set.
  • :cost - each call's cost, as [usd: 0.001], or a function of the server's result.
  • :gated - which tools need a person's approval: true, false, or tool name globs, as ["create_*"]. Tools not marked read-only unless set.
  • :trusted - true to treat answers as the deployment's own, not labelled "outside". false unless set.

Summary

Types

cost()
t()

Functions

gated?(server, name, read_only)

Returns whether calls to the tool name need a person's approval.

labels(server)

Returns the labels on the server's answers: ["outside"], or [] if it's trusted.

new!(name, opts)

Builds a server named name. Raises ArgumentError on an unknown option.

offers?(server, name)

Returns whether the server offers its tool name, given only and except.

prefix(server)

Returns the prefix for the server's tool names.

reachable(server)

Returns :ok if the server may be reached now, or {:error, reason}.

transport(server, token)

Returns the transport options for reaching the server with the caller's token.

Types

cost()

@type cost() :: keyword(number()) | (map() -> %{optional(atom()) => number()})

t()

@type t() :: %WardrikMCP.Server{
  check: (String.t() -> :ok | {:error, String.t()}) | nil,
  cost: cost() | nil,
  credential_env: String.t() | nil,
  credential_header: String.t(),
  credential_name: String.t() | nil,
  credential_scheme: String.t(),
  except: [String.t()] | nil,
  gated: boolean() | [String.t()] | nil,
  max_result_bytes: pos_integer(),
  mcp: atom() | nil,
  name: String.t(),
  only: [String.t()] | nil,
  prefix: String.t() | nil,
  timeout: pos_integer(),
  transport: {:stdio | :streamable_http, keyword()},
  trusted: boolean()
}

Functions

gated?(server, name, read_only)

@spec gated?(t(), String.t(), boolean()) :: boolean()

Returns whether calls to the tool name need a person's approval.

labels(server)

@spec labels(t()) :: [String.t()]

Returns the labels on the server's answers: ["outside"], or [] if it's trusted.

new!(name, opts)

@spec new!(atom() | String.t(), keyword()) :: t()

Builds a server named name. Raises ArgumentError on an unknown option.

offers?(server, name)

@spec offers?(t(), String.t()) :: boolean()

Returns whether the server offers its tool name, given only and except.

prefix(server)

@spec prefix(t()) :: String.t()

Returns the prefix for the server's tool names.

reachable(server)

@spec reachable(t()) :: :ok | {:error, String.t()}

Returns :ok if the server may be reached now, or {:error, reason}.

Always :ok without a check. With one, a command is refused and the URL must pass it.

transport(server, token)

@spec transport(t(), String.t() | nil) :: {:stdio | :streamable_http, keyword()}

Returns the transport options for reaching the server with the caller's token.