> ## Documentation Index > Fetch the complete documentation index at: https://docs.gtm-api.com/llms.txt > Use this file to discover all available pages before exploring further. # Add conversation participants > Add one or more members to an existing thread on LinkedIn (outward action). Pass the conversation sid + participant_ln_ids (1..20 bare LinkedIn profile ids, the ACoA... ln_id of a connection or conversation participant; never a urn: string, the SDK wraps the id itself and a URN is wrapped twice and refused); a 1:1 thread is promoted to a group. item is the stored thread as it was before the call (the participant list follows on the next inbox sync); result carries status success and the activity_log_sid of the call. A LinkedIn refusal is a typed error (409 linkedin_refused, or the account-level 409 / 422 codes), never a success with a failed status. Contract: - MCP tool `add_linkedin_conversation_participants`, registry package `mcp.linkedin/linkedin_conversations`, mount `linkedin.messaging`. - Operation `action`, response envelope `action`. - Flags: dangerous: the MCP layer gates it behind a preview/commit token, and the effect cannot be undone through this API; paced: a call spends the `messaging_general` smart-limit bucket of the account it runs on, and calls of one bucket are spaced per account. A short wait is slept by the server; a longer one answers 429 `rate_limited` with `context.retry_after`, and the same call succeeds from that moment. Parallel calls on one account queue behind each other. ## OpenAPI ````yaml /api-reference/linkedin/openapi.yaml post /api/linkedin-conversations/{sid}/add-participants openapi: 3.0.3 info: title: 'GTM API public contract: gtm.service.linkedin' description: >- Connected LinkedIn accounts and everything driven through them: account health and smart limits, conversations and messages, the connection graph, outbound posting, scraping, profile and company enrichment, and the antidetect browsers that execute it all. GENERATED. This document is projected from the Zod MCP tool registry in `product/mcp/gtm.mcp` (one tool per public endpoint, 1:1). Do not edit it by hand; edit the tool definition and regenerate with `pnpm openapi:public`. Surface: the public `/api` contract of `gtm.service.linkedin`, 189 operations. This is the only OpenAPI document the platform publishes. Internal (`/internal`) and health endpoints are deliberately absent: they are not part of any contract, they can change without notice, and the service source is their only description. Conventions: - Auth is a bearer JWT, optionally narrowed by the `Team-SID` header. - Every success body is an MCP envelope: `success: true` plus one typed `operation` shape (`search`, `get`, `create`, `update`, `delete`, `metrics`, `group_by`, `action`), and a `meta` block with `trace_id` for support. - Every failure is the same `McpError` envelope with a code from a fixed 16-code taxonomy, so a client maps errors once. - Lists page with `page_size` (0 to 500, default 50) plus an opaque forward `cursor`; `page_size: 0` returns counts only. - On `GET` and `DELETE`, object-valued query parameters (`filter`, `sort`) travel as JSON text and array-valued ones repeat as `name[]=value`. - The MCP-only `_meta` field (usage analytics) never reaches the backend and is not part of this contract. version: '1.0' contact: name: GTM API url: https://gtm-api.com email: support@gtm-api.com license: name: Proprietary url: https://gtm-api.com/license servers: - url: https://app.gtm-api.com/linkedin/v4 description: Production, through the app.gtm-api.com gateway security: - BearerJwt: [] TeamSid: [] tags: - name: antidetect_browser_logs description: >- Registry package `mcp.linkedin/antidetect_browser_logs`, served on MCP mount `linkedin.browsers`. - name: antidetect_browser_proxies description: >- Registry package `mcp.linkedin/antidetect_browser_proxies`, served on MCP mount `linkedin.browsers`. - name: antidetect_browsers description: >- Registry package `mcp.linkedin/antidetect_browsers`, served on MCP mount `linkedin.browsers`. - name: cloud_browser_sessions description: >- Registry package `mcp.linkedin/cloud_browser_sessions`, served on MCP mount `linkedin.browsers`. - name: cloud_browsers description: >- Registry package `mcp.linkedin/cloud_browsers`, served on MCP mount `linkedin.browsers`. - name: data_requests description: >- Registry package `mcp.linkedin/data_requests`, served on MCP mount `linkedin.data`. - name: linkedin_account_activity_log description: >- Registry package `mcp.linkedin/linkedin_account_activity_log`, served on MCP mount `linkedin.account-monitor`. - name: linkedin_account_block_log description: >- Registry package `mcp.linkedin/linkedin_account_block_log`, served on MCP mount `linkedin.account-monitor`. - name: linkedin_account_quota_hits description: >- Registry package `mcp.linkedin/linkedin_account_quota_hits`, served on MCP mount `linkedin.account-monitor`. - name: linkedin_account_smart_limits description: >- Registry package `mcp.linkedin/linkedin_account_smart_limits`, served on MCP mount `linkedin.accounts`. - name: linkedin_account_snapshots description: >- Registry package `mcp.linkedin/linkedin_account_snapshots`, served on MCP mount `linkedin.account-monitor`. - name: linkedin_account_sync_runs description: >- Registry package `mcp.linkedin/linkedin_account_sync_runs`, served on MCP mount `linkedin.account-monitor`. - name: linkedin_accounts description: >- Registry package `mcp.linkedin/linkedin_accounts`, served on MCP mount `linkedin.accounts`. - name: linkedin_auto_scrape_results description: >- Registry package `mcp.linkedin/linkedin_auto_scrape_results`, served on MCP mount `linkedin.auto-scrapes`. - name: linkedin_auto_scrape_runs description: >- Registry package `mcp.linkedin/linkedin_auto_scrape_runs`, served on MCP mount `linkedin.auto-scrapes`. - name: linkedin_auto_scrapes description: >- Registry package `mcp.linkedin/linkedin_auto_scrapes`, served on MCP mount `linkedin.auto-scrapes`. - name: linkedin_benchmarks description: >- Registry package `mcp.linkedin/linkedin_benchmarks`, served on MCP mount `linkedin.account-monitor`. - name: linkedin_connection_invitations description: >- Registry package `mcp.linkedin/linkedin_connection_invitations`, served on MCP mount `linkedin.network`. - name: linkedin_connection_requests description: >- Registry package `mcp.linkedin/linkedin_connection_requests`, served on MCP mount `linkedin.network`. - name: linkedin_connections description: >- Registry package `mcp.linkedin/linkedin_connections`, served on MCP mount `linkedin.network`. - name: linkedin_conversations description: >- Registry package `mcp.linkedin/linkedin_conversations`, served on MCP mount `linkedin.messaging`. - name: linkedin_custom_requests description: >- Registry package `mcp.linkedin/linkedin_custom_requests`, served on MCP mount `linkedin.platform`. - name: linkedin_enrichment description: >- Registry package `mcp.linkedin/linkedin_enrichment`, served on MCP mount `linkedin.enrichment`. - name: linkedin_followers description: >- Registry package `mcp.linkedin/linkedin_followers`, served on MCP mount `linkedin.network`. - name: linkedin_messages description: >- Registry package `mcp.linkedin/linkedin_messages`, served on MCP mount `linkedin.messaging`. - name: linkedin_posting description: >- Registry package `mcp.linkedin/linkedin_posting`, served on MCP mount `linkedin.content`. - name: linkedin_scraping description: >- Registry package `mcp.linkedin/linkedin_scraping`, served on MCP mount `linkedin.scraping`. paths: /api/linkedin-conversations/{sid}/add-participants: post: tags: - linkedin_conversations summary: Add conversation participants description: >- Add one or more members to an existing thread on LinkedIn (outward action). Pass the conversation sid + participant_ln_ids (1..20 bare LinkedIn profile ids, the ACoA... ln_id of a connection or conversation participant; never a urn: string, the SDK wraps the id itself and a URN is wrapped twice and refused); a 1:1 thread is promoted to a group. item is the stored thread as it was before the call (the participant list follows on the next inbox sync); result carries status success and the activity_log_sid of the call. A LinkedIn refusal is a typed error (409 linkedin_refused, or the account-level 409 / 422 codes), never a success with a failed status. Contract: - MCP tool `add_linkedin_conversation_participants`, registry package `mcp.linkedin/linkedin_conversations`, mount `linkedin.messaging`. - Operation `action`, response envelope `action`. - Flags: dangerous: the MCP layer gates it behind a preview/commit token, and the effect cannot be undone through this API; paced: a call spends the `messaging_general` smart-limit bucket of the account it runs on, and calls of one bucket are spaced per account. A short wait is slept by the server; a longer one answers 429 `rate_limited` with `context.retry_after`, and the same call succeeds from that moment. Parallel calls on one account queue behind each other. operationId: add_linkedin_conversation_participants parameters: - name: sid in: path required: true description: LinkedIn conversation sid (ln_cv_…). schema: type: string minLength: 18 maxLength: 18 pattern: ^ln_cv_ description: LinkedIn conversation sid (ln_cv_…). requestBody: required: true content: application/json: schema: $ref: '#/components/schemas/AddLinkedinConversationParticipantsRequest' responses: '200': description: '`action` success envelope.' content: application/json: schema: $ref: >- #/components/schemas/AddLinkedinConversationParticipantsResponse 4XX: $ref: '#/components/responses/McpClientError' 5XX: $ref: '#/components/responses/McpServerError' components: schemas: AddLinkedinConversationParticipantsRequest: type: object description: Request body of `add_linkedin_conversation_participants`. properties: participant_ln_ids: type: array items: type: string minLength: 1 maxLength: 64 minItems: 1 maxItems: 20 description: 'Bare LinkedIn profile ids (ACoA...) to add, 1..20; not urn: strings.' required: - participant_ln_ids AddLinkedinConversationParticipantsResponse: type: object properties: success: type: boolean enum: - true operation: type: string enum: - action action: type: string description: kebab-case verb; matches the route segment. item: type: object nullable: true properties: sid: type: string team_sid: type: string linkedin_account_sid: type: string conversation_hash: type: string description: >- LinkedIn's OWN thread id, the 2-…== value that appears in a messaging URL and in every raw wire payload. Not our sid. This is the id a user has in hand when they name a thread, so filter.conversation_hash is how you turn it into a conversation sid. messenger_type: type: string enum: - linkedin - sales_navigator - recruiter description: >- Messenger surface: the basic LinkedIn messenger, Sales Navigator, or the LinkedIn Recruiter inbox (the threads a recruiter seat owns; the counterpart is a recruiter_id). ln_member_id: type: string nullable: true ln_id: type: string nullable: true sn_id: type: string nullable: true recruiter_id: type: string nullable: true description: >- The counterpart's LinkedIn Recruiter (talent) profile id (AEMAA…): the ONLY id a messenger_type='recruiter' thread carries, and what send_linkedin_recruiter_message dispatches as the reply recipient. It does not decode to ln_member_id. Null on the other two surfaces. nickname: type: string nullable: true participants: type: array nullable: true items: type: object properties: ln_member_id: type: string nullable: true ln_id: type: string nullable: true sn_id: type: string nullable: true recruiter_id: type: string nullable: true nickname: type: string nullable: true full_name: type: string nullable: true headline: type: string nullable: true picture_url: type: string nullable: true is_muted: type: boolean nullable: true unread_count: type: integer nullable: true description: >- LinkedIn's own unread counter for the thread, synced from both messenger wires. A LEVEL, not a high-water mark: reading the thread elsewhere lowers it. null = never synced, which is not the same as a synced 0. mark-read / mark-unread mirror it immediately (read sets 0; unread sets a floor of 1, because after the verb all we truly know is "more than zero"). event_count: type: number last_activity_at: type: string nullable: true last_stored_message_at: type: string nullable: true last_message_sync_at: type: string nullable: true created_at: type: string updated_at: type: string deleted_at: type: string nullable: true required: - sid - team_sid - linkedin_account_sid - conversation_hash - messenger_type - ln_member_id - ln_id - sn_id - recruiter_id - nickname - participants - is_muted - unread_count - event_count - last_activity_at - last_stored_message_at - last_message_sync_at - created_at - updated_at - deleted_at result: type: object properties: status: type: string enum: - success description: >- The only value this verb answers with: a refusal is a typed error, never a status. activity_log_sid: type: string nullable: true description: The linkedin-account-activity-log row of the call (ln_al_). required: - status - activity_log_sid meta: type: object properties: trace_id: type: string description: UUID v7; same 128-bit value as the X-Trace-Id header. span_id: type: string pattern: ^[0-9a-f]{16}$ description: 16 hex chars, root span of this request. timestamp: type: string description: ISO 8601 UTC (Y-m-dTH:i:sZ), response time. duration_ms: type: integer minimum: 0 description: Server-side wall clock. team_sid: type: string nullable: true description: >- The team this call ran in (the token team, or the team_sid override). Null when unauthenticated; absent from pre-2026-08-20 backends. actor_type: type: string nullable: true description: >- user | agent | api_key | system. Null when unauthenticated; absent from pre-2026-08-20 backends. required: - trace_id - span_id - timestamp - duration_ms pacing: type: object properties: linkedin_account_sid: type: string description: The account whose bucket the call spent. limit_type: type: string description: The smart-limit bucket the call spent, e.g. send_messages. next_call_after: type: string description: >- ISO 8601, the same form as retry_after: the moment this same call goes through again without waiting. The next pacing slot while the day has budget left, the daily reset when it has none, the end of a LinkedIn lock while one stands. remaining_today: type: integer minimum: 0 description: >- daily_limit minus done_today_count of that bucket, after this call. required: - linkedin_account_sid - limit_type - next_call_after - remaining_today required: - success - operation - action - item - result - meta McpError: type: object properties: success: type: boolean enum: - false error: type: object properties: code: type: string enum: - validation_failed - nothing_to_update - not_found - relation_not_found - invalid_transition - limit_exceeded - payment_required - duplicate_rejected - conflict - delete_blocked - unauthorized - forbidden - rate_limited - internal_error - service_unavailable - not_implemented message: type: string recoverable: type: boolean suggestion: type: string field_errors: type: object additionalProperties: type: array items: type: object properties: rule: type: string message: type: string required: - rule - message blockers: type: array items: type: object properties: type: type: string description: >- Machine-readable blocker type (active_flow, pending_tasks, …). severity: type: string enum: - hard - soft description: >- hard = external action required; soft = acknowledge is enough. description: type: string entity_sid: type: string nullable: true count: type: integer resolution: type: string description: 'Hard: tool name to call. Soft: code for acknowledge[].' resolution_hint: type: string required: - type - severity - description - entity_sid - resolution - resolution_hint context: type: object additionalProperties: {} required: - code - message - recoverable meta: type: object properties: trace_id: type: string description: UUID v7; same 128-bit value as the X-Trace-Id header. span_id: type: string pattern: ^[0-9a-f]{16}$ description: 16 hex chars, root span of this request. timestamp: type: string description: ISO 8601 UTC (Y-m-dTH:i:sZ), response time. duration_ms: type: integer minimum: 0 description: Server-side wall clock. team_sid: type: string nullable: true description: >- The team this call ran in (the token team, or the team_sid override). Null when unauthenticated; absent from pre-2026-08-20 backends. actor_type: type: string nullable: true description: >- user | agent | api_key | system. Null when unauthenticated; absent from pre-2026-08-20 backends. required: - trace_id - span_id - timestamp - duration_ms required: - success - error responses: McpClientError: description: >- MCP error envelope. `error.code` is one of validation_failed, nothing_to_update, not_found, relation_not_found, invalid_transition, limit_exceeded, payment_required, duplicate_rejected, conflict, delete_blocked, unauthorized, forbidden, rate_limited, not_implemented. content: application/json: schema: $ref: '#/components/schemas/McpError' McpServerError: description: >- MCP error envelope with `error.code` internal_error or service_unavailable. content: application/json: schema: $ref: '#/components/schemas/McpError' securitySchemes: BearerJwt: type: http scheme: bearer bearerFormat: JWT description: >- Access token issued by gtm.service.id. Its `access_identity` claim carries `team_sid`, `actor_sid` and `actor_type`, and that team scope is authoritative. TeamSid: type: apiKey in: header name: Team-SID description: >- Team scope for tokens that do not carry one. Ignored when the token already names a team. ```` This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.