Initial Commit

openspec/changes/enterprise-slack-client/proposal.md

@@ -0,0 +1,191 @@
+# OpenSpec Change: enterprise-slack-client
+
+- **Change ID**: enterprise-slack-client
+- **Package**: `@suaveplan/slack-client`
+- **Category**: universal
+- **Target path**: `universal/social/slack-client`
+- **Status**: IN PROGRESS
+- **Date**: 2026-04-24
+- **Reference spec**: `/mnt/s/web/suaveplan/enterprise/slack-client.md`
+
+---
+
+## Summary
+
+Deliver `@suaveplan/slack-client` on the genesis branch from scratch at enterprise quality. The package provides a generic Slack API client: Web API method wrappers for messaging (`chat.postMessage`, `chat.update`, `chat.delete`), channel management (`conversations.*`), user info (`users.*`), file uploads, Block Kit message builder, Incoming Webhooks, Event subscription parsing with signature verification, slash-command payload parsing, interactive component payload handling, and a `SlackClient` facade. Injectable fetch and crypto; no Slack SDK dependency. Genesis adds structured errors, Zod schemas, OTel instrumentation, retry with circuit breaker, and `AbortSignal` cancellation.
+
+---
+
+## Current-state audit (genesis)
+
+The package does not exist on genesis yet — this is a fresh build.
+
+---
+
+## Available workspace deps on genesis
+
+| Package | Role |
+|---|---|
+| `@suaveplan/error` (`workspace:^`) | `SlackError`; `SLACK.*` error codes |
+| `@suaveplan/types` (`workspace:^`) | `LoggerLike`, `Clock` |
+| `@suaveplan/retry` (`workspace:^`) | Retry + circuit breaker for API calls |
+| `@suaveplan/crypto` (`workspace:^`) | HMAC-SHA256 request signature verification |
+| `zod` (`catalog:forms`) | Schema validation |
+| `@opentelemetry/api` (`catalog:observability`) | Spans + counters |
+
+Dev deps: `vitest`, `@vitest/coverage-istanbul`, `fast-check` (all `catalog:testing`).
+
+---
+
+## Public API surface
+
+### `SlackClient`
+
+```ts
+class SlackClient {
+  constructor(options: SlackClientOptions)
+
+  // Messaging
+  postMessage(options: PostMessageOptions): Promise<SlackMessageResponse>
+  updateMessage(options: UpdateMessageOptions): Promise<SlackMessageResponse>
+  deleteMessage(channel: string, ts: string): Promise<void>
+
+  // Channels
+  listConversations(options?: ListConversationsOptions): AsyncGenerator<SlackChannel>
+  getConversationInfo(channel: string): Promise<SlackChannel>
+
+  // Users
+  getUserInfo(userId: string): Promise<SlackUser>
+  getUserByEmail(email: string): Promise<SlackUser>
+
+  // Files
+  uploadFile(options: FileUploadOptions): Promise<SlackFile>
+
+  // Webhooks
+  postToWebhook(url: string, payload: WebhookPayload): Promise<void>
+}
+
+interface SlackClientOptions {
+  token: string
+  signingSecret?: string   // for event verification
+  retryOptions?: RetryOptions
+  fetch?: typeof globalThis.fetch
+  clock?: Clock
+  logger?: LoggerLike
+}
+```
+
+### Block Kit builder
+
+```ts
+function createMessage(text: string): MessageBuilder
+interface MessageBuilder {
+  section(text: string): MessageBuilder
+  divider(): MessageBuilder
+  image(url: string, altText: string): MessageBuilder
+  actions(...elements: ActionElement[]): MessageBuilder
+  context(...elements: ContextElement[]): MessageBuilder
+  build(): SlackBlocks
+}
+```
+
+### Event handling
+
+```ts
+function verifySlackSignature(
+  body: string,
+  timestamp: string,
+  signature: string,
+  signingSecret: string,
+  options?: { maxAgeSeconds?: number; clock?: Clock }
+): boolean
+
+function parseSlackEvent(body: unknown): SlackEvent
+function parseSlashCommand(body: unknown): SlashCommand
+function parseInteractivePayload(body: unknown): InteractivePayload
+```
+
+### Error codes
+
+```ts
+type SlackErrorCode =
+  | 'SLACK_AUTH_FAILED'
+  | 'SLACK_API_ERROR'
+  | 'SLACK_RATE_LIMITED'
+  | 'SLACK_SIGNATURE_INVALID'
+  | 'SLACK_CHANNEL_NOT_FOUND'
+  | 'SLACK_USER_NOT_FOUND'
+  | 'SLACK_ABORTED'
+```
+
+---
+
+## Genesis additions
+
+1. **`SlackError`** extends `SuaveplanError` with seven stable codes.
+2. **Zod schemas** for `PostMessageOptions`, `SlackEvent`, `SlashCommand`, `InteractivePayload`, `SlackChannel`, `SlackUser`, `SlackFile`.
+3. **Rate-limit handling** — respects `Retry-After` header from Slack 429 responses; integrates with `@suaveplan/retry`.
+4. **Circuit breaker** — wraps all API calls via `@suaveplan/retry` circuit breaker; opens after 5 consecutive failures.
+5. **OTel instrumentation** — span `slack.api_call` with attribute `slack.method`; counter `slack.api_total`; histogram `slack.api_duration_ms`.
+6. **Property-based tests** — Block Kit builder produces valid JSON structures for arbitrary sequences of builder calls.
+
+---
+
+## File layout
+
+```text
+universal/social/slack-client/
+  package.json
+  tsconfig.json
+  vitest.config.ts
+  src/
+    index.ts
+    error-codes.ts
+    constants/
+      index.ts
+    types/
+      common.ts
+      common.md
+    core/
+      slack-client/
+        slack-client.ts
+        slack-client.md
+        slack-client.types.ts
+        slack-client.test.ts
+        index.ts
+      api-caller/
+        api-caller.ts
+        api-caller.md
+        api-caller.test.ts
+        index.ts
+    blocks/
+      message-builder/
+        message-builder.ts
+        message-builder.md
+        message-builder.test.ts
+        index.ts
+    events/
+      event-parser/
+        event-parser.ts
+        event-parser.md
+        event-parser.test.ts
+        index.ts
+      signature-verifier/
+        signature-verifier.ts
+        signature-verifier.md
+        signature-verifier.test.ts
+        index.ts
+    __benchmarks__/
+      slack-client.bench.ts
+  tests/
+    integration.test.ts
+    property.test.ts
+```
+
+---
+
+## Impact
+
+**Downstream consumers**: `@suaveplan/message-bridge`, `@suaveplan/notification-channel`.
+
+**Workspace dep prerequisites**: `@suaveplan/error`, `@suaveplan/types`, `@suaveplan/retry`, `@suaveplan/crypto`.