Documentation
¶
Overview ¶
Package mcp_client is a minimal MCP Streamable HTTP client used by the ailang CLI to fetch fresh content (prompts, docs search, stdlib) from mcp.ailang.sunholo.com when --source=mcp or --source=auto is in effect.
Goals:
- Tiny surface: just enough to call one tool per CLI command
- Version-locked: every call passes for_version=<CLI's compile-time version> and the response's served_for is checked. Mismatch -> ErrVersionMismatch so the caller falls back silently to embedded.
- Bounded latency: 1.5s default timeout, configurable via env
- Stateless: opens + closes one MCP session per call. Caching is the caller's responsibility (see internal/prompt for the on-disk cache).
Usage:
c := mcp_client.New(mcp_client.Options{
BaseURL: os.Getenv("AILANG_MCP_URL"), // empty -> default prod
AILangVersion: version.Version,
Timeout: 1500 * time.Millisecond,
})
out, err := c.CallTool(ctx, "prompt_get", map[string]any{
"forVersion": c.AILangVersion,
"kind": "agent",
})
Index ¶
Constants ¶
const DefaultTimeout = 1500 * time.Millisecond
DefaultTimeout caps a single MCP round-trip. Network failures should not stall an interactive `ailang prompt` command; the embedded fallback wins after this elapses.
const DefaultURL = "https://mcp.ailang.sunholo.com/mcp/"
DefaultURL is the canonical MCP endpoint for ailang.sunholo.com.
const ProtocolVersion = "2024-11-05"
ProtocolVersion is the MCP wire version we negotiate during initialize.
Variables ¶
var ErrVersionMismatch = errors.New("mcp_client: server has no content for this AILANG version")
ErrVersionMismatch means the server returned content tagged for a different AILANG version (typically because the snapshot doesn't have content for the caller's version). Callers should silently fall back to embedded.
Functions ¶
This section is empty.
Types ¶
type Client ¶
type Client struct {
// contains filtered or unexported fields
}
Client is a minimal MCP Streamable HTTP client.
func (*Client) AILangVersion ¶
AILangVersion returns the CLI version this client was constructed with.
func (*Client) CallTool ¶
func (c *Client) CallTool(ctx context.Context, toolName string, args map[string]any) (map[string]any, error)
CallTool runs initialize -> notifications/initialized -> tools/call against the MCP endpoint and returns the parsed response payload.
If the response is an envelope of the form {served_for, data, ...} (which every version-scoped MCP tool returns) AND served_for != AILangVersion AND AILangVersion was passed in args under "forVersion", the call returns ErrVersionMismatch so the caller can silently fall back to embedded.
If the tool returned an error envelope ({error, detail}), the call returns *ErrToolError with the parsed code/detail.
type ErrToolError ¶
ErrToolError means the tool call returned an MCP error envelope (isError=true) or a structured {error: ...} JSON body. The body is preserved in the error.
func (*ErrToolError) Error ¶
func (e *ErrToolError) Error() string
type Options ¶
type Options struct {
// BaseURL is the MCP endpoint. Empty resolves to DefaultURL.
BaseURL string
// AILangVersion is the CLI's compile-time version, passed as for_version
// in every tool call.
AILangVersion string
// Timeout is per-request. Zero resolves to DefaultTimeout.
Timeout time.Duration
// HTTPClient lets tests inject a fake transport.
HTTPClient *http.Client
}
Options bundles the CLI-side config surface.
Source Files