feat: Add thread mark-read command

skills/comms-cli/SKILL.md

@@ -106,6 +106,9 @@ tdc thread reply <ref> "content" --file ./a.png  # Attach a file (repeatable; co
 tdc thread done <ref>                 # Preview thread archive (requires --yes to execute)
 tdc thread done <ref> --yes           # Archive thread (mark done)
 tdc thread done <ref> --yes --json    # Archive and return status as JSON
+tdc thread mark-read <ref>        # Mark a thread read
+tdc thread mark-read <ref> <ref> --yes # Mark multiple threads read
+printf "123\n456\n" | tdc thread mark-read --dry-run # Preview bulk mark-read from stdin
 tdc thread mute <ref>             # Mute thread for 60 minutes (default)
 tdc thread mute <ref> --minutes 480  # Mute for custom duration
 tdc thread mute <ref> --json      # Mute and return { id, mutedUntil } as JSON
@@ -379,7 +382,7 @@ Commands accept flexible references:
 - **Comms URLs**: Full `https://comms.todoist.com/...` URLs (parsed automatically)
 - **Fuzzy names**: For workspaces/users - `"My Workspace"` or partial matches
 
-## Piping Content
+## Piping Input
 
 Commands that accept content (`thread create`, `thread reply`, `comment update`, `conversation reply`, `msg update`) auto-detect piped stdin:
 
@@ -391,6 +394,12 @@ echo "Quick reply" | tdc conversation reply <ref>
 
 If no content argument is provided and no stdin is piped, the CLI opens `$EDITOR` for interactive input. In non-TTY environments (e.g. when called by an agent or in a pipeline), the editor is automatically skipped and the command fails fast with an actionable error message. Use `--non-interactive` to force this behavior even in a TTY, or `--interactive` to override auto-detection.
 
+`tdc thread mark-read` also accepts thread refs from stdin, one per line:
+
+```bash
+printf "123\n456\n" | tdc thread mark-read --yes
+```
+
 ## Common Workflows
 
 **View by URL (auto-routes to the right command):**

src/commands/thread/index.ts

@@ -5,6 +5,7 @@ import { createThread } from './create.js'
 import { deleteThread } from './delete.js'
 import { markThreadDone } from './mutate.js'
 import { muteThread, unmuteThread } from './mute.js'
+import { markThreadRead } from './read.js'
 import { renameThread } from './rename.js'
 import { replyToThread } from './reply.js'
 import { updateThread } from './update.js'
@@ -113,6 +114,28 @@ Examples:
         )
         .action(markThreadDone)
 
+    const markReadCmd = thread
+        .command('mark-read [thread-refs...]')
+        .description('Mark a thread read for the current user')
+        .option('--yes', 'Skip confirmation for bulk operations')
+        .option('--dry-run', 'Show what would happen without executing')
+        .option('--json', 'Output result as JSON')
+        .addHelpText(
+            'after',
+            `
+Examples:
+  tdc thread mark-read 12345
+  tdc thread mark-read 12345 67890 --yes
+  printf "12345\\n67890\\n" | tdc thread mark-read --yes`,
+        )
+        .action((refs, options) => {
+            if (refs.length === 0 && process.stdin.isTTY) {
+                markReadCmd.help()
+                return
+            }
+            return markThreadRead(refs, options)
+        })
+
     thread
         .command('delete <thread-ref>')
         .description('Permanently delete a thread')

src/commands/thread/read.ts

@@ -0,0 +1,162 @@
+import type { CommsApi, Thread } from '@doist/comms-sdk'
+import { getCommsClient } from '../../lib/api.js'
+import { CliError } from '../../lib/errors.js'
+import { readStdinToEnd } from '../../lib/input.js'
+import type { MutationOptions } from '../../lib/options.js'
+import { formatJson, pluralize } from '../../lib/output.js'
+import { assertChannelIsPublic } from '../../lib/public-channels.js'
+import { resolveThreadId } from '../../lib/refs.js'
+
+export type MarkThreadReadOptions = MutationOptions
+
+type LoadedThread = {
+    thread: Thread
+    isUnread: boolean
+}
+
+type MarkReadStatus = {
+    id: string
+    isRead: true
+}
+
+type TextStatus = 'changed' | 'preview' | 'unchanged'
+
+export async function markThreadRead(
+    refs: string[],
+    options: MarkThreadReadOptions,
+): Promise<void> {
+    const rawRefs = await collectThreadRefs(refs)
+    if (rawRefs.length === 0) {
+        throw new CliError(
+            'INVALID_REF',
+            'No thread references provided. Pass refs as arguments or pipe them via stdin.',
+        )
+    }
+
+    const needsConfirmation = rawRefs.length > 1 && !options.yes && !options.dryRun
+    if (options.json && needsConfirmation) {
+        throw new CliError(
+            'MISSING_YES_FLAG',
+            '--yes is required to execute bulk mark-read in --json mode.',
+        )
+    }
+
+    const client = await getCommsClient()
+    const unreadCache = new Map<number, Set<string>>()
+    const jsonStatuses: MarkReadStatus[] = []
+    const textStatuses: TextStatus[] = []
+
+    for (const rawRef of rawRefs) {
+        const threadId = resolveThreadId(rawRef)
+        const loaded = await loadThread(client, unreadCache, threadId)
+
+        if (!loaded.isUnread) {
+            jsonStatuses.push({ id: threadId, isRead: true })
+            textStatuses.push('unchanged')
+            if (!options.json) {
+                console.log(`Thread ${threadLabel(loaded.thread)} is already read.`)
+            }
+            continue
+        }
+
+        if (needsConfirmation || options.dryRun) {
+            jsonStatuses.push({ id: threadId, isRead: true })
+            textStatuses.push('preview')
+            if (!options.json) {
+                const prefix = options.dryRun ? 'Dry run: would' : 'Would'
+                console.log(`${prefix} mark read thread ${threadLabel(loaded.thread)}.`)
+            }
+            continue
+        }
+
+        await client.threads.markRead({
+            id: threadId,
+            objIndex: getLatestObjIndex(loaded.thread),
+        })
+        unreadCache.get(loaded.thread.workspaceId)?.delete(threadId)
+
+        jsonStatuses.push({ id: threadId, isRead: true })
+        textStatuses.push('changed')
+        if (!options.json) {
+            console.log(`Thread ${threadLabel(loaded.thread)} marked read.`)
+        }
+    }
+
+    if (options.json && !options.dryRun) {
+        console.log(formatJson(jsonStatuses))
+        return
+    }
+
+    if (!options.json && rawRefs.length > 1) {
+        printSummary(textStatuses)
+    }
+
+    if (!options.json && needsConfirmation) {
+        console.log('Use --yes to confirm.')
+    }
+}
+
+async function collectThreadRefs(refs: string[]): Promise<string[]> {
+    const inlineRefs = refs.map((ref) => ref.trim()).filter(Boolean)
+
+    const stdinContent = await readStdinToEnd()
+    if (!stdinContent) return inlineRefs
+
+    const stdinRefs = stdinContent
+        .split(/\r?\n/)
+        .map((line) => line.trim())
+        .filter((line) => line !== '' && !line.startsWith('#'))
+
+    return [...inlineRefs, ...stdinRefs]
+}
+
+async function loadThread(
+    client: CommsApi,
+    unreadCache: Map<number, Set<string>>,
+    threadId: string,
+): Promise<LoadedThread> {
+    const thread = await client.threads.getThread(threadId)
+    await assertChannelIsPublic(thread.channelId, thread.workspaceId)
+
+    let unreadIds = unreadCache.get(thread.workspaceId)
+    if (!unreadIds) {
+        const unread = await client.threads.getUnread(thread.workspaceId)
+        unreadIds = new Set(unread.data.map((unreadThread) => unreadThread.threadId))
+        unreadCache.set(thread.workspaceId, unreadIds)
+    }
+
+    return { thread, isUnread: unreadIds.has(thread.id) }
+}
+
+function getLatestObjIndex(thread: Thread): number {
+    return Math.max(
+        ...[thread.lastComment?.objIndex, thread.lastObjIndex, thread.commentCount, 0]
+            .filter((value): value is number => typeof value === 'number')
+            .map((value) => Math.max(value, 0)),
+    )
+}
+
+function threadLabel(thread: Thread): string {
+    return `${thread.title} (${thread.id})`
+}
+
+function printSummary(statuses: TextStatus[]): void {
+    const summary = [
+        summarizeStatus(statuses, 'changed'),
+        summarizeStatus(statuses, 'unchanged'),
+        summarizeStatus(statuses, 'preview'),
+    ].filter(Boolean)
+
+    console.log('')
+    console.log(`Summary: ${summary.join(', ')}`)
+}
+
+function summarizeStatus(statuses: TextStatus[], status: TextStatus): string | null {
+    const count = statuses.filter((value) => value === status).length
+    if (count === 0) {
+        return null
+    }
+
+    const noun = status === 'preview' ? pluralize(count, 'preview') : pluralize(count, 'thread')
+    return status === 'preview' ? `${count} ${noun}` : `${count} ${status} ${noun}`
+}