REST APIJSON over HTTPS, versioned in the path, with cursor pagination. An OpenAPI 3.1 document lets you generate your own client. A key sees exactly what its creator sees.GET https://api.replysync.co/v1/threads

MCP serverHerd's tools in Claude, Cursor or any MCP client. Hosted with OAuth, so you connect with the URL alone. Sending always shows a summary first.https://mcp.replysync.co/mcp

CLIOne command per tool, same names as the API. Readable tables by default, --json for scripts, and it asks before sending.$ npm i -g replysync

MCP serverHerd's tools in Claude, Cursor or any MCP client. Hosted with OAuth, so you connect with the URL alone. Sending always shows a summary first.https://mcp.replysync.co/mcp

CLIOne command per tool, same names as the API. Readable tables by default, --json for scripts, and it asks before sending.$ npm i -g replysync

MCP serverHerd's tools in Claude, Cursor or any MCP client. Hosted with OAuth, so you connect with the URL alone. Sending always shows a summary first.https://mcp.replysync.co/mcp

CLIOne command per tool, same names as the API. Readable tables by default, --json for scripts, and it asks before sending.$ npm i -g replysync

MCP serverHerd's tools in Claude, Cursor or any MCP client. Hosted with OAuth, so you connect with the URL alone. Sending always shows a summary first.https://mcp.replysync.co/mcp

CLIOne command per tool, same names as the API. Readable tables by default, --json for scripts, and it asks before sending.$ npm i -g replysync

Developers

Everything Herd can do, you can call.

Herd, the REST API, the MCP server and the CLI all call the same tools. Connect Claude, Claude Code or Cursor with one URL, then ask who's waiting on a reply.

How it's built

One registry, four ways in.

Each tool is defined once. Herd, the API routes, the MCP tools and the CLI commands are all generated from it, so a new tool shows up everywhere at once.

One tool registryinput · output · scope · effect

Herd

REST API

MCP server

CLI

REST API

Safe by default.

Anything that sends, merges, archives, disconnects or removes access needs "confirm": true. Without it you get a 202 with a plain-English summary and a token to resend with.

Count interested replies still waiting

curl https://api.replysync.co/v1/threads \
  -H "Authorization: Bearer rs_live_…" \
  -G -d label=interested -d status=waiting

Base URL	`https://api.replysync.co/v1`
Auth	Bearer key (rs_live_…), shown once, stored hashed
Versioning	v1 only adds fields. Nothing is removed or renamed.
Errors	Written for people, with a request_id for support
SDK	replysync on npm, generated from OpenAPI

threads:readdrafts:writesends:writeclients:writeauto_mode:write

Only a key with sends:write can send. A key can never do more than the person who made it.

MCP server

Ask your AI who's waiting.

Hosted at mcp.replysync.co with OAuth. You only see your own clients, and anything that sends or deletes asks first. Comes with two prompts: triage_morning and weekly_client_summary.

Claude Code

> claude mcp add --transport http replysync https://mcp.replysync.co/mcp
✓ Connected to replysync
Sign in with OAuth to finish
> who replied interested today?

Claude

Who's still waiting on a reply at Fenwick?

replysync · list_threads

Used 1 tool

3 interested replies, all drafted. The oldest is Tomas, waiting 31 hours.

Tomas ReyesInterested31h

Ines DuarteInterested22h

Chloe MartinMeeting9h

Cursorprompt

Run triage_morning for all my clients

replysync · triage_morning

Worked for 6 sec

Grouped this morning's replies by what should happen next.

Ready to send · 2

Tomas ReyesDraft ready

Ana PiresDraft ready

Needs you · 1

Marco FeldPricing

$ npx -y replysync-mcp
replysync MCP server on stdio
weekly_client_summary ✓

CLI

Morning triage from your terminal.

Install with npm, log in once, and set a default client. Sending or deleting asks Proceed? [y/N] unless you pass --yes. --json returns the same shape as the API.

▾● Waiting3

Tomas ReyesFenwick31h

Ines DuarteOakridge22h

Chloe MartinFieldstone9h

▾● Sent today4

Ana PiresLindqvist8:02

Henrik SandLindqvist8:10

Lea BrandtFenwick8:31

Omar HaddadOakridge8:40

▾○ Not now2

Marco FeldOakridgeQ1

Sara LindFieldstoneJan

~/agencyzsh

01$ replysync threads --waiting

02CLIENT LEAD LABEL WAITING

03Fenwick Tomas Reyes interested 31h

04Oakridge Ines Duarte interested 22h

05Fieldstone Chloe Martin meeting 9h

07$ replysync send --all --client fenwick

08Send 2 drafts through Instantly? Proceed? [y/N] y

09✓ Sent to Tomas Reyes

10✓ Sent to Ines Duarte

12$ replysync threads --json | jq length

131

14$ echo $? # 0 ok · 2 needs confirm · 3 rate limited

150

Webhooks

Know the moment it happens.

Every delivery is signed and carries an event ID for de-duplication. Failures retry 5 times over about an hour. After 20 failures in a row the endpoint pauses and we tell you.

reply.receivedreply.labeleddraft.approvedmessage.sentmeeting.bookedclient.createdauto_mode.report

Limits

Rate limits.

Sends are queued under your sequencer's own limits and never rejected. Limits may change before launch.

Type	Limit
Reads	600 per minute per key, up to 20 at once
Writes	120 per minute per key
Headers	RateLimit-* on every response, Retry-After on a 429
Audit	Every API, MCP and CLI call is logged: who, what and when

Hehe, that tickles!

Developers

Get a key
and build.

Access opens in small groups, so create an account first. Your key lives in the app.

Say hi to Herd and get set up

Already have an account? Sign in

Everything Herd can do, you can call.

One registry, four ways in.

Safe by default.

Ask your AI who's waiting.

Morning triage from your terminal.

Know the moment it happens.

Rate limits.

Get a keyand build.

Get a key
and build.