opencode/packages/core/src/mcp/guidance.ts

101 lines
3.9 KiB
TypeScript

export * as McpGuidance from "./guidance"
import { makeLocationNode } from "../effect/app-node"
import { Context, Effect, Layer, Schema } from "effect"
import { AgentV2 } from "../agent"
import { PermissionV2 } from "../permission"
import { McpTool } from "../tool/mcp"
import { MCP } from "./index"
import { Instructions } from "../instructions/index"
const Summary = Schema.Struct({
server: Schema.String,
instructions: Schema.String,
})
type Summary = typeof Summary.Type
const entries = (servers: ReadonlyArray<Summary>) =>
servers.flatMap((server) => [
` <server name="${server.server}">`,
` Use tools from this server through \`execute\` under \`tools[${JSON.stringify(McpTool.group(server.server))}]\`.`,
...server.instructions.split("\n").map((line) => ` ${line}`),
" </server>",
])
const render = (servers: ReadonlyArray<Summary>) =>
["<mcp_instructions>", ...entries(servers), "</mcp_instructions>"].join("\n")
const update = (previous: ReadonlyArray<Summary>, current: ReadonlyArray<Summary>) => {
const diff = Instructions.diffByKey(
previous,
current,
(server) => server.server,
(before, after) => before.instructions !== after.instructions,
)
// Additions and removals render as small deltas; anything else restates the full list.
if (diff.changed.length > 0 || (diff.added.length === 0 && diff.removed.length === 0))
return [
"The available MCP server instructions have changed. This list supersedes the previous one.",
render(current),
].join("\n")
return [
...(diff.added.length === 0
? []
: ["New MCP server instructions are available in addition to those previously listed:", ...entries(diff.added)]),
...(diff.removed.length === 0
? []
: [
`Instructions for the following MCP servers are no longer available: ${diff.removed.map((server) => server.server).join(", ")}.`,
]),
].join("\n")
}
export interface Interface {
readonly load: (agent: AgentV2.Selection) => Effect.Effect<Instructions.Instructions>
}
export class Service extends Context.Service<Service, Interface>()("@opencode/v2/McpGuidance") {}
export const layer = Layer.effect(
Service,
Effect.gen(function* () {
const mcp = yield* MCP.Service
return Service.of({
load: Effect.fn("McpGuidance.load")(function* (selection) {
const agent = selection.info
if (!agent) return Instructions.empty
const source = (value: ReadonlyArray<Summary> | Instructions.Removed) =>
Instructions.make<ReadonlyArray<Summary>>({
key: Instructions.Key.make("core/mcp-guidance"),
codec: Schema.toCodecJson(Schema.Array(Summary)),
read: Effect.succeed(value),
render: {
initial: render,
changed: update,
removed: () => "MCP server instructions are no longer available.",
},
})
if (PermissionV2.evaluate("execute", "*", agent.permissions).effect === "deny")
return source(Instructions.removed)
const [instructions, tools] = yield* Effect.all([mcp.instructions(), mcp.tools()], {
concurrency: "unbounded",
})
// Instructions are useful only when this agent can reach at least one server tool.
const visible = instructions
.filter((item) => {
const owned = tools.filter((tool) => tool.server === item.server)
return owned.some(
(tool) =>
PermissionV2.evaluate(McpTool.name(tool.server, tool.name), "*", agent.permissions).effect !== "deny",
)
})
.map((item) => ({ server: item.server, instructions: item.instructions }))
.toSorted((a, b) => a.server.localeCompare(b.server))
return source(visible.length === 0 ? Instructions.removed : visible)
}),
})
}),
)
export const node = makeLocationNode({ service: Service, layer, deps: [MCP.node] })