opencode/packages/core/src/tool/mcp.ts
2026-06-30 08:37:44 -05:00

101 lines
4.2 KiB
TypeScript

export * as McpTool from "./mcp"
import { createHash } from "node:crypto"
import { ToolFailure } from "@opencode-ai/llm"
import { McpEvent } from "@opencode-ai/schema/mcp-event"
import { Effect, Exit, type JsonSchema, Layer, Scope, Semaphore, Stream } from "effect"
import { makeLocationNode } from "../effect/app-node"
import { EventV2 } from "../event"
import { MCP } from "../mcp"
import { Tool } from "./tool"
import { Tools } from "./tools"
import { ToolRegistry } from "./registry"
const MAX_NAME_LENGTH = 64
const HASH_LENGTH = 8
const sanitize = (value: string) => value.replace(/[^A-Za-z0-9_-]/g, "_")
// Deterministic short suffix used to keep overlong or colliding names unique and stable across restarts.
const hashSuffix = (raw: string) => "_" + createHash("sha1").update(raw).digest("hex").slice(0, HASH_LENGTH)
const fit = (base: string, raw: string) => base.slice(0, MAX_NAME_LENGTH - HASH_LENGTH - 1) + hashSuffix(raw)
/**
* Registry/permission action name for an MCP tool: V1-compatible `<server>_<tool>` so existing deny
* rules keep working. Sanitized to a valid tool name, prefixed when it would not start with a letter,
* and hashed down when it would exceed the 64-char limit.
*/
export const name = (server: string, tool: string) => {
const joined = sanitize(server) + "_" + sanitize(tool)
const base = /^[A-Za-z]/.test(joined) ? joined : "mcp_" + joined
return base.length > MAX_NAME_LENGTH ? fit(base, `${server}\u0000${tool}`) : base
}
const toContent = (part: MCP.ToolResultContent): Tool.Content =>
part.type === "text" ? { type: "text", text: part.text } : { type: "file", data: part.data, mime: part.mimeType }
const errorText = (content: ReadonlyArray<MCP.ToolResultContent>) =>
content
.flatMap((part) => (part.type === "text" ? [part.text] : []))
.join("\n")
.trim()
export const layer = Layer.effectDiscard(
Effect.gen(function* () {
const mcp = yield* MCP.Service
const tools = yield* Tools.Service
const events = yield* EventV2.Service
const scope = yield* Scope.Scope
const lock = Semaphore.makeUnsafe(1)
let current: Scope.Closeable | undefined
const make = (server: MCP.ServerName, tool: MCP.Tool) =>
Tool.make({
description: tool.description ?? "",
jsonSchema: (tool.inputSchema as JsonSchema.JsonSchema | undefined) ?? { type: "object", properties: {} },
execute: (input) =>
Effect.gen(function* () {
const result = yield* mcp.callTool({ server, name: tool.name, args: (input ?? {}) as Record<string, unknown> }).pipe(
Effect.catchTags({
"MCP.NotFoundError": (error) => new ToolFailure({ message: `MCP server "${error.server}" is not available` }),
"MCP.ToolCallError": (error) => new ToolFailure({ message: error.message }),
}),
)
if (result.isError)
return yield* new ToolFailure({ message: errorText(result.content) || "MCP tool returned an error" })
return { structured: result.structured ?? {}, content: result.content.map(toContent) }
}),
})
// Register the current tool set under a fresh child scope, then close the previous one so the
// registry never has a gap where MCP tools disappear mid-swap.
const reconcile = lock.withPermit(
Effect.gen(function* () {
const used = new Set<string>()
const record: Record<string, Tool.AnyTool> = {}
for (const tool of yield* mcp.tools()) {
const initial = name(tool.server, tool.name)
const key = used.has(initial) ? fit(initial, `${tool.server}\u0000${tool.name}`) : initial
used.add(key)
record[key] = make(tool.server, tool)
}
const next = yield* Scope.fork(scope)
yield* tools.register(record).pipe(Scope.provide(next), Effect.orDie)
if (current) yield* Scope.close(current, Exit.void)
current = next
}),
)
yield* reconcile.pipe(Effect.forkScoped)
yield* events
.subscribe(McpEvent.ToolsChanged)
.pipe(Stream.runForEach(() => reconcile), Effect.forkScoped({ startImmediately: true }))
}),
)
export const node = makeLocationNode({
name: "mcp-tools",
layer,
deps: [ToolRegistry.toolsNode, MCP.node, EventV2.node],
})