Changelog
What changed on the Simp Connect platform, newest first, including the 2026-10-05 replacement of the MCP server on the 2026-07-28 specification.
Between releases, tools only gain optional inputs and additive outputs. On 2026-10-05 the MCP server was replaced rather than versioned: the 2026-07-28 MCP specification changed the transport, the authorization model and the task model together, so there was no additive path, and nothing of the old server runs alongside the new one.
2026-10-05#
The MCP server is replaced. It speaks MCP 2026-07-28 only, at https://voice.simpmobile.com/mcp: stateless (no initialize, no Mcp-Session-Id, no HTTP+SSE), routed by the Mcp-Method and Mcp-Name headers, with server/discover, cacheable lists (ttlMs) and Multi Round-Trip Requests. /api/mcp and /api/mcp/v1 are gone.
Eight outcome-oriented tools. create_task (participants by name, phone, email, handle or party id; kind call, get_answer, send_update or follow_up; objective, options, respond_by, boundaries), get_task, list_tasks, respond_to_decision, cancel_task, get_user_info, support_ask and support_cases. create_call_task, check_task_status, list_recent_tasks, respond_to_input_request and respond_to_approval_request are removed, and so are scheduled_for and recurrence: Simp decides when and how each person is reached. See the Tool reference and Deadlines and timing.
The MCP tasks extension. A Simp task is an MCP task: tasks/get, tasks/update and tasks/cancel for clients that declare io.modelcontextprotocol/tasks.
Permission modes gain the allowed_task_kinds right; a connection granted before it reads as calls only.
Webhooks (api_version v2) gain task.participant_answered and task.result_ready, and every payload now carries ids, labels, states and option ids only: no summary, no prompt. See Webhooks.
Authentication on the MCP 2026-07-28 rules. Clients identify themselves with a Client ID Metadata Document (their client_id is the HTTPS URL of a JSON document they host); dynamic client registration and /oauth/register are removed. Every authorization response carries iss (RFC 9207). Codes and tokens are bound to the resource (RFC 8707 resource) and to the issuer that minted them, so a connection made before today connects again. ChatGPT's stable callback and https://chatgpt.com/oauth/client.json work. See Authentication.
2026-08-19#
Versioned endpoint. The canonical MCP URL is now https://voice.simpmobile.com/mcp. The previous /api/mcp path stayed as an alias until the server was replaced on 2026-10-05. New connections should use the versioned URL (it is also the connector cache key, see Troubleshooting).
Scheduling. create_call_task accepts optional scheduled_for (ISO 8601 with offset, within 90 days, inside the user's 08:00 to 21:00 local window) and recurrence (daily / weekly / monthly, up to 26 occurrences, approved once per series). cancel_task gains an optional scope: "series". Scheduled tasks get a reminder push about ten minutes before dialling. (Removed on 2026-10-05.)
Persona and number selection. create_call_task accepts optional persona (id or exact name) and from_number (id or E.164 of a number the user owns). Unknown values return teaching errors listing the user's own options. get_user_info now returns personas and numbers with ids.
Permission modes. Every connection has a mode: ask_every_time (default), notify_only, or rights_based (fail-closed rights: task types, daily cap, known contacts, scheduling, series), plus a per-connection sharing envelope. get_user_info returns the mode as connection. See Permission modes.
Webhooks. Signed, at-least-once task events (task.completed, task.failed, task.input_needed, task.approval_needed, task.status_changed) with an ownership handshake, HMAC signatures with 24-hour rotation overlap, a retry ladder, dead-lettering and auto-disable. Clients may declare a default webhook_url in their DCR metadata. See Webhooks.
Sandbox. A Simp-owned test number answered by a scripted callee, for end-to-end calls that never ring a stranger and are never billed. Fail-closed caps. See the Quickstart.
Security posture. Refresh-token rotation with reuse detection (a replayed rotated token revokes the whole grant and notifies the user); all transcripts, summaries and mid-call prompts delivered delimiter-wrapped as third-party content; create-time destination pre-checks; global per-client rate limits alongside the per-user ones.
Status card. check_task_status results carry metadata for a read-only in-chat status card on clients that render MCP app resources. Approval stays in the Simp app.
Tool annotations. All seven tools now publish MCP annotations (read-only, destructive, idempotent, open-world).
Documentation. This site replaces the single-page /connect: generated tool reference and errors catalogue, per-client guides, and an LLM-readable corpus at /llms.txt and /llms-full.txt.
2026-08-14#
title and headline on create_call_task became optional with server-side defaults (they were briefly required, which broke connectors holding a cached schema - the origin of the "never add a required field" rule). ChatGPT connections gained an auto-approve option, now generalised as the notify_only mode.
2026-08-08#
Simp Connect launched: OAuth 2.0 authorisation server with PKCE, dynamic client registration (RFC 7591), the seven-tool MCP server with pre-dial approval, per-user rate limits, and Connected apps management in the Simp app.