feat(message): compose editor + Slack-native drafts (#83)

README.md

@@ -6,7 +6,7 @@ Guiding principle:
 
 - **Token-efficient** — (compact JSON, minimal duplication, and empty/null fields pruned) so LLMs can consume results cheaply.
 - **Zero-config auth** — Auth just works if you have Slack Desktop (with fallbacks available). No Python dependency.
-- **Human-in-the-loop** — When appropriate (not in CI environments), loop humans in. Ex: `message draft`
+- **Human-in-the-loop** — When appropriate (not in CI environments), loop humans in. Ex: `message compose`
   <img width="1228" height="741" alt="image" src="https://github.com/user-attachments/assets/92ecbb71-18ca-4516-a874-c83c154b0709" />
 
 ## Getting started
@@ -35,6 +35,7 @@ nix run github:stablyai/agent-slack
 - **Search**: messages + files (with filters)
 - **Artifacts**: auto-download snippets/images/files to local paths for agents
 - **Write**: send now or schedule delivery, edit/delete messages, add reactions (bullet lists auto-render as native Slack rich text)
+- **Compose & drafts**: open a browser editor (`message compose`), or manage Slack-native drafts that show up in your Slack client (`message draft`)
 - **Channels**: list conversations, create channels, and invite users by id/handle/email
 - **Canvas**: create Slack canvases from Markdown and fetch them as Markdown
 
@@ -79,7 +80,12 @@ agent-slack
 │   ├── scheduled
 │   │   ├── list                   # list pending scheduled messages
 │   │   └── cancel <id>            # cancel a pending scheduled message
-│   ├── draft <target> [text]      # open Slack-like editor in browser
+│   ├── compose <target> [text]    # open Slack-like editor in browser
+│   ├── draft                      # Slack-native drafts (appear in your Slack client)
+│   │   ├── list                   # list Slack-native drafts
+│   │   ├── create <target> <text> # create a Slack-native draft
+│   │   ├── update <id> <text>     # replace a draft's text
+│   │   └── delete <id>            # delete a draft
 │   ├── edit  <target> <text>      # edit a message
 │   ├── delete <target>            # delete a message
 │   └── react
@@ -203,24 +209,46 @@ Optional:
 agent-slack message get "https://workspace.slack.com/archives/C123/p1700000000000000" --include-reactions
 ```
 
-### Draft a message (browser editor)
+### Compose a message (browser editor)
 
 Opens a Slack-like WYSIWYG editor in your browser for composing messages with full formatting support (bold, italic, strikethrough, links, lists, quotes, code, code blocks).
 
 ```bash
 # Open editor for a channel
-agent-slack message draft "#general"
+agent-slack message compose "#general"
 
 # Open editor with initial text
-agent-slack message draft "#general" "Here's my update"
+agent-slack message compose "#general" "Here's my update"
 
 # Reply in a thread
-agent-slack message draft "https://workspace.slack.com/archives/C123/p1700000000000000"
+agent-slack message compose "https://workspace.slack.com/archives/C123/p1700000000000000"
 ```
 
 After sending, the editor shows a "View in Slack" link to the posted message.
 
-`message draft` is send-capable. In CI, it skips the browser editor and immediately sends supplied text; do not use it for a compose-only request in a noninteractive environment.
+`message compose` is send-capable. In CI, it skips the browser editor and immediately sends supplied text; do not use it for a compose-only request in a noninteractive environment.
+
+### Slack-native drafts
+
+Manage drafts through Slack's own drafts API, so they show up natively in the user's Slack client (mobile and desktop) ready to review and send. Requires browser-style auth (xoxc/xoxd).
+
+> [!NOTE]
+> These commands use Slack's **undocumented** internal `drafts.*` client endpoints (the same ones the Slack app uses), authenticated with your own browser session. They act only as you, on your own drafts — nothing is exposed that you can't already see, and `create` posts nothing. But because the endpoints are unsupported: their behavior may change without notice, and on **Enterprise Grid** this style of session-token API use can be flagged by Slack's security/anomaly detection. This is the same auth model the rest of agent-slack already uses (`later`, `unreads`, `search`); use it where that's acceptable.
+
+```bash
+# List unsent drafts
+agent-slack message draft list
+
+# Draft a message to a channel (shows up in Slack's Drafts section)
+agent-slack message draft create "#general" "Here's my update"
+
+# Draft a thread reply
+agent-slack message draft create "https://workspace.slack.com/archives/C123/p1700000000000000" "Looking into it"
+
+# Replace a draft's text, or delete it
+agent-slack message draft update "DR_ID" "Here's my revised update"
+agent-slack message draft delete "DR_ID"
+```
 
 ### Reply, edit, delete, and react
 

llms.txt

@@ -17,7 +17,8 @@
 - Token-efficient compact JSON output so LLMs can consume Slack data cheaply
 - Zero-config auth: auto-detects Slack Desktop credentials on macOS, Windows, and Linux — with Chrome, Brave, and Firefox fallbacks
 - Multi-workspace Slack management with automatic workspace resolution
-- Human-in-the-loop message drafting via browser-based WYSIWYG rich text editor
+- Human-in-the-loop message composing via browser-based WYSIWYG rich text editor (`message compose`)
+- Slack-native drafts that appear in the user's Slack client via `message draft` (list/create/update/delete)
 - Slack canvas creation from Markdown files or inline content, plus export to Markdown
 - Slack channel creation, user invites, and Slack Connect external invites
 

skills/agent-slack/SKILL.md

@@ -1,6 +1,6 @@
 ---
 name: agent-slack
-description: "Slack CLI for agents: read URLs/threads/history/unreads/later/canvases/workflows, create canvases from Markdown, search messages/files, download attachments, lookup users, list/create/invite channels, open DMs, draft messages, schedule sends, and explicit sends/edits/deletes/reactions/mark-read/uploads."
+description: "Slack CLI for agents: read URLs/threads/history/unreads/later/canvases/workflows, create canvases from Markdown, search messages/files, download attachments, lookup users, list/create/invite channels, open DMs, compose messages, manage Slack-native drafts, schedule sends, and explicit sends/edits/deletes/reactions/mark-read/uploads."
 ---
 
 # agent-slack
@@ -20,7 +20,7 @@ If a capability named here is absent from installed help, report version skew in
 
 - Read and search freely.
 - Perform write actions only when explicitly requested: sends, edits, deletes, reactions, invitations, channel or canvas creation, mark-read operations, scheduling or canceling delivery, uploads, Later state/reminder changes, DM/group-DM creation, and `workflow run`. Workflow runs can execute downstream actions.
-- For compose- or review-only requests, return proposed text without invoking Slack. `message draft` is send-capable; use it only when the user explicitly asks to open the interactive editor. In CI or another noninteractive environment, do not invoke it without separate authorization to send immediately: CI skips the editor and sends supplied text.
+- For compose- or review-only requests, return proposed text without invoking Slack, or use `message draft create` to add a Slack-native draft the user can review and send (nothing is posted). `message compose` is send-capable; use it only when the user explicitly asks to open the interactive editor. In CI or another noninteractive environment, do not invoke it without separate authorization to send immediately: CI skips the editor and sends supplied text.
 
 ## Workflow
 
@@ -36,6 +36,8 @@ Named `later remind --in` values such as `tomorrow` or `monday` also use the exe
 
 Ordinary `message send` and `message edit` calls auto-convert lists. `message send --blocks` uses supplied blocks, while `message send --attach` sends its initial comment without automatic list conversion. Inside auto-converted lists, use Slack's `<URL|label>` syntax because CommonMark `[label](URL)` links are not converted into labeled link elements.
 
+Slack-native drafts (`message draft list|create|update|delete`) manage drafts that appear in the user's Slack client; `create` posts nothing. They use undocumented session endpoints and require browser-style auth (xoxc/xoxd).
+
 ## Conditional references
 
 - Read [references/targets.md](references/targets.md) only when choosing between a message URL, channel, or user target, or when resolving multiple workspaces.

skills/agent-slack/references/targets.md

@@ -10,7 +10,7 @@ A URL supplies the workspace, channel, and message timestamp. With a URL target:
 
 - `message get`, `edit`, `delete`, and `react` operate on that message.
 - `message list` returns the thread root and all replies.
-- `message send` replies in that message's thread. `message draft` does the same unless `--thread-ts` explicitly overrides the URL-derived thread.
+- `message send` replies in that message's thread. `message compose` and `message draft create` do the same unless `--thread-ts` explicitly overrides the URL-derived thread.
 - `channel mark` marks through that message timestamp; `--ts` explicitly overrides the timestamp. It rejects `--workspace` because the URL supplies it.
 
 Use a channel name or a `C...`, `G...`, or `D...` channel ID only when no URL is available:
@@ -19,7 +19,7 @@ Use a channel name or a `C...`, `G...`, or `D...` channel ID only when no URL is
 - `message list` reads channel history unless `--thread-ts` or `--ts` selects a thread.
 - `channel mark` requires `--ts`.
 
-Among `message` subcommands, only `message send` accepts a `U...` or `W...` user ID as a target; it opens or reuses that user's direct-message channel. Treat `U`- and `W`-prefixed user IDs equivalently.
+Among `message` subcommands, `message send` and `message draft create` accept a `U...` or `W...` user ID as a target; it opens or reuses that user's direct-message channel. `message draft update --channel` can likewise re-address a draft to a DM. Treat `U`- and `W`-prefixed user IDs equivalently.
 
 Use `user dm-open <users...>` with one to eight other user IDs or handles to get a DM or group-DM channel ID, then use that channel ID for message operations. The authenticated caller is implicit.
 

src/cli/draft-actions.ts → src/cli/compose-actions.ts

@@ -5,7 +5,7 @@ import { resolveChannelId, resolveChannelName, normalizeChannelInput } from "../
 import { warnOnTruncatedSlackUrl } from "./message-url-warning.ts";
 import { openDraftEditor } from "./draft-server.ts";
 
-export async function draftMessage(input: {
+export async function composeMessage(input: {
   ctx: CliContext;
   targetInput: string;
   initialText?: string;
@@ -14,7 +14,7 @@ export async function draftMessage(input: {
   const target = parseMsgTarget(String(input.targetInput));
   if (target.kind === "user") {
     throw new Error(
-      "message draft does not support user ID targets. Use a channel name, channel ID, or message URL.",
+      "message compose does not support user ID targets. Use a channel name, channel ID, or message URL.",
     );
   }
 

src/cli/message-command.ts

@@ -9,8 +9,9 @@ import {
   sendMessage,
   type MessageCommandOptions,
 } from "./message-actions.ts";
-import { draftMessage } from "./draft-actions.ts";
+import { composeMessage } from "./compose-actions.ts";
 import { registerScheduledMessageCommand } from "./message-scheduled-command.ts";
+import { registerMessageDraftCommand } from "./message-draft-command.ts";
 
 function collectOptionValue(value: string, previous: string[] = []): string[] {
   return [...previous, value];
@@ -253,14 +254,15 @@ export function registerMessageCommand(input: { program: Command; ctx: CliContex
     });
 
   registerScheduledMessageCommand({ messageCmd, ctx: input.ctx });
+  registerMessageDraftCommand({ messageCmd, ctx: input.ctx });
 
   messageCmd
-    .command("draft")
+    .command("compose")
     .description(
-      "Open a send-capable rich editor; CI skips the editor and immediately sends supplied text",
+      "Open a send-capable rich editor in the browser; CI skips the editor and immediately sends supplied text",
     )
     .argument("<target>", "Slack message URL, #name/name, or channel id")
-    .argument("[text]", "Initial draft text (sent immediately when CI skips the editor)")
+    .argument("[text]", "Initial message text (mrkdwn; sent immediately when CI skips the editor)")
     .option(
       "--workspace <url>",
       "Workspace selector (full URL or unique substring; needed when using #channel/channel id across multiple workspaces)",
@@ -276,7 +278,7 @@ export function registerMessageCommand(input: { program: Command; ctx: CliContex
         { workspace?: string; threadTs?: string },
       ];
       try {
-        const payload = await draftMessage({
+        const payload = await composeMessage({
           ctx: input.ctx,
           targetInput,
           initialText: text,