LemlistMCP connector for Claude and ChatGPT

HOW in lib/lemlist.py. Endpoint set cached at reference/docs/lemlist/raw/llms.txt.

Auth & config

• Base URL: https://api.lemlist.com/api · Auth: HTTP Basic — API key as the password, empty username (client sets auth=('', key)). Env LEMLIST_API_KEY; never hardcode. get_team() = safe read-only pilot.
• Core paths CONFIRMED from developer.lemlist.com (ReadMe .md + llms.txt, 2026-06-01). QUIRK: version=v2 query param required on get_campaigns (defaulted) and other v2 reads. Add-lead is POST /api/campaigns/{id}/leads/ with email in the body (not the path). Rate limit 20 req/2s. Full index: reference/docs/lemlist/raw/endpoints.md; endpoints not covered by a listed method (companies, inbox, schedules, etc.) aren't available yet.

Approval gates (sending)

• start_campaign begins sending; add_lead_to_campaign enrolls a lead into active sending — approval-gate (pilot, confirm, then batch).

Operations

Campaigns: get_campaigns, get_campaign, get_campaign_stats, start_campaign, pause_campaign. Leads: add_lead_to_campaign, remove_lead_from_campaign. Contacts: get_contacts, upsert_contact. Plus get_activities, enrich_lead, get_team. The callable surface below has the full list, including campaign/sequence creation.

Handoff

Activation layer (multichannel). Enriched+validated leads → add to campaign → review → start. get_activities feeds reply/interest tracking back to the ATS.

Field notes (production experience)

Field-shape note: these are vendor-native operational notes. The client returns the raw vendor JSON and uses the method names in this file — read field shapes accordingly (no normalized-wrapper / result.data. prefix).

Flow: create/list campaign -> add sequence steps -> add contacts in small batches (10-25) -> review in the Lemlist UI (web_url returned on create/update) -> monitor activities/inbox.

• Step types: email, linkedinInvite, linkedinSend, linkedinVisit, manual, phone, api, whatsappMessage, conditional, sendToAnotherCampaign.
• Delays are in DAYS (0 = immediate, 2 = 2 days). Passing 172800 ("seconds") triggers a > 1500 days API error.
• Lead export states: all, contacted, interested, notInterested, emailsBounced, paused, emailsSent, emailsOpened, emailsReplied.
• Activity types: emailsSent, emailsOpened, emailsClicked, emailsReplied, emailsBounced, emailsUnsubscribed.
• Inbox sends need IDs: send_email requires send_user_id, send_user_email, send_user_mailbox_id - list the inbox first to discover them.
• Dedup: duplicate emails / linkedin_url within a batch are rejected; cross-batch dupes can 409.
• Prefer editing sequence steps while the campaign is draft/paused.

Callable surface

Call via the CLI: hyreflow tools execute lemlist <method> --payload '{...}' (preview with --dry-run; hyreflow tools get lemlist <method> returns the live contract + cost). Base: https://api.lemlist.com/api. Only the methods listed below are callable.

• add_conditional_step(sequence_id: str, condition_key: str, *, delay_type: str = 'within', delay: int | None = None, index: int | None = None) -> Any — POST /api/sequences/{sequenceId}/steps with type='conditional' — adds a branch point and RETURNS conditions: [{sequenceId, label, key, delayType, delay}, {sequenceId, fallback:true}] — i.e. an accepted-branch sequenceId AND a fallback (not-met) sequenceId. Add follow-up steps into those branch sequence ids via add_sequence_step(branch_seq_id, ...). condition_key e.g.
• add_lead_to_campaign(campaign_id: str, *, email: str | None = None, linkedin_url: str | None = None, payload: dict | None = None, variables: dict | None = None, **query) -> Any — POST /api/campaigns/{campaignId}/leads/ — add a SINGLE lead (CONFIRMED). This is a single-lead call with top-level fields — there is NO contacts:[…] array shape (that 400s). email is OPTIONAL — a LinkedIn-only lead works with just linkedin_url (verified live 2026-06-02). Provide at least one of email / linkedin_url. Standard fields go in payload: firstName, lastName, companyName, jobTitle, phone, companyDomain, icebreaker, timezone, contactOwner, picture.
• add_lead_variables(lead_id: str, variables: dict) -> Any — POST /api/leads/{leadId}/variables?=&… — CREATE per-lead CUSTOM merge variables so {{name}} renders in the sequence. Custom field names + values are passed as QUERY params, NOT a JSON body (CONFIRMED from developer.lemlist.com). ⚠️ CREATE-only: a name that collides with a lemlist default var (email, firstName, lastName, picture, phone, linkedinUrl, companyName, companyDomain, icebreaker) OR an already-set custom var ERRORS — pass only NEW custom keys. Needs the leadId (the _id from add_lead_to_campaign's response). variables: {name: value, …}. Returns {ok: true}.
• add_sequence_step(sequence_id: str, type: str = 'email', *, subject: str | None = None, message: str | None = None, delay: int | None = None, index: int | None = None, **fields) -> Any — POST /api/sequences/{sequenceId}/steps — add a step. type ∈ email|manual|phone|api| linkedinVisit|linkedinInvite|linkedinSend|linkedinVoiceNote|conditional|whatsappMessage|sms|… Email step: subject (≤400), message (HTML body), delay (days, 0–1500; default 0 first/1 after), index (position, -1=end). No sender required. Extra fields (altMessage, url, method, conditionKey, images, videos…) via **fields. CONFIRMED live.
• create_campaign(name: str, *, timezone: str | None = None, auto_review: bool | None = None, auto_review_conditions: list[str] | None = None) -> Any — POST /api/campaigns — create a campaign; returns state: running, NOT draft, so pause it before building the sequence.
• delete_sequence_step(sequence_id: str, step_id: str) -> Any — DELETE /api/sequences/{sequenceId}/steps/{stepId} — remove a step. CONFIRMED live 2026-06-02 (note: needs the sequenceId in the path — /sequences/steps/{id} returns 405).
• enrich_lead(payload: dict) -> Any — POST /enrich — enrich a lead (see api-reference/endpoints/enrich).
• get_activities(**params) -> Any — GET /activities — outreach activity events (opens, replies, etc.).
• get_campaign(campaign_id: str) -> Any
• get_campaign_leads(campaign_id: str, *, state: str | None = None, limit: int | None = None, **params) -> Any — GET /api/campaigns/{campaignId}/leads/ — read the leads currently in a campaign (synchronous; the practical counterpart to the async CSV export). Returns an array of lead objects with their fields, INCLUDING any custom merge variables set via add_lead_variables — so it's how you VERIFY variables persisted. Query: state (scanned|contacted|interested|notInterested|paused|…), limit (default 100, max 500). Sorted newest-first; no cursor paging. CONFIRMED from developer.lemlist.com.
• get_campaign_sequences(campaign_id: str) -> Any — GET /api/campaigns/{id}/sequences — the campaign's sequence(s) (each has _id = sequenceId).
• get_campaign_stats(campaign_id: str, *, start_date: str, end_date: str, **params) -> Any — GET /api/campaigns/{campaignId}/stats — campaign performance over a date window.
• get_campaigns(*, version: str = 'v2', **params) -> Any — GET /api/campaigns — list campaigns. version=v2 is REQUIRED (defaulted here); supports offset/limit (max 100)/page, sortBy=createdAt, sortOrder, status, createdBy.
• get_contacts(**params) -> Any
• get_team() -> Any — GET /team — team info (safe read-only pilot).
• pause_campaign(campaign_id: str) -> Any
• remove_lead_from_campaign(campaign_id: str, email: str) -> Any
• start_campaign(campaign_id: str) -> Any — POST /campaigns/{id}/start — starts sending (outreach!). Approval-gate.
• update_sequence_step(sequence_id: str, step_id: str, **fields) -> Any — PATCH /api/sequences/{sequenceId}/steps/{stepId} — update a step (subject, message, delay, …).
• upsert_contact(payload: dict) -> Any — Create/update a contact (see api-reference/endpoints/contacts/upsert-contact).