> ## 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. # Create LinkedIn comment > Leave ONE outbound comment on any LinkedIn post (wire create-comment): entity_urn takes a post urn in any family or a post URL carrying one, and the comment is written on the post's social thread (see entity_urn). Outward and fire-on-success: the post does NOT need to be tracked or owned by us. Identity-bound: linkedin_account_sid REQUIRED, spends the comment_posts bucket (30/day at a 360 s floor), saturation returns 429. Reply to an existing comment via parent_comment_urn. mentions turns exact substrings of text into clickable profile links ({profile_id, name} pairs; a name missing or out of order is a 422 with no dispatch spent). Returns the created comment ref plus the activity-log row. Sends once per client_reference and place (the post as LinkedIn files it, or the comment a reply answers): a repeat is answered, never sent twice; on a 409 read error.context.send_outcome, never resend under a new key. To react use react_linkedin_post; to resolve a post URL use get_activity_urn_by_url. Contract: - MCP tool `create_linkedin_comment`, registry package `mcp.linkedin/linkedin_posting`, mount `linkedin.content`. - 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; mass action: this verb's own request accepts a filter or targets[] set, which the owning service drains; step eligible: gtm.service.orchestration can run this verb as a mass-action plan step, once per item; paced: a call spends the `comment_posts` 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-posting/comment 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-posting/comment: post: tags: - linkedin_posting summary: Create LinkedIn comment description: >- Leave ONE outbound comment on any LinkedIn post (wire create-comment): entity_urn takes a post urn in any family or a post URL carrying one, and the comment is written on the post's social thread (see entity_urn). Outward and fire-on-success: the post does NOT need to be tracked or owned by us. Identity-bound: linkedin_account_sid REQUIRED, spends the comment_posts bucket (30/day at a 360 s floor), saturation returns 429. Reply to an existing comment via parent_comment_urn. mentions turns exact substrings of text into clickable profile links ({profile_id, name} pairs; a name missing or out of order is a 422 with no dispatch spent). Returns the created comment ref plus the activity-log row. Sends once per client_reference and place (the post as LinkedIn files it, or the comment a reply answers): a repeat is answered, never sent twice; on a 409 read error.context.send_outcome, never resend under a new key. To react use react_linkedin_post; to resolve a post URL use get_activity_urn_by_url. Contract: - MCP tool `create_linkedin_comment`, registry package `mcp.linkedin/linkedin_posting`, mount `linkedin.content`. - 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; mass action: this verb's own request accepts a filter or targets[] set, which the owning service drains; step eligible: gtm.service.orchestration can run this verb as a mass-action plan step, once per item; paced: a call spends the `comment_posts` 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: create_linkedin_comment requestBody: required: true content: application/json: schema: $ref: '#/components/schemas/CreateLinkedinCommentRequest' responses: '200': description: '`action` success envelope.' content: application/json: schema: $ref: '#/components/schemas/CreateLinkedinCommentResponse' 4XX: $ref: '#/components/responses/McpClientError' 5XX: $ref: '#/components/responses/McpServerError' components: schemas: CreateLinkedinCommentRequest: type: object description: Request body of `create_linkedin_comment`. properties: linkedin_account_sid: type: string minLength: 18 maxLength: 18 pattern: ^ln_ac_ description: >- LinkedIn account sid (ln_ac_…), the authoring account. Identity-bound: REQUIRED, posts publish AS this account. entity_urn: type: string minLength: 1 maxLength: 512 description: >- The post to comment on. A comment is written on the post's social thread, and LinkedIn refuses one sent to any other key (live 2026-09-16: the activity urn of a ugcPost company post answered linkedin_400, its ugcPost urn took the comment), so a post handle is re-addressed at its thread before the wire. urn:li:ugcPost: and urn:li:groupPost:- are the thread and go as is. urn:li:activity: and urn:li:share: cost one post read first (the read enrich_linkedin_post_details makes, on this account, cached 7 days): a share post is commented at its activity urn, a ugcPost post at its ugcPost urn, a repost without commentary at the original. A post the read returns null for (deleted, or not visible to the account) is refused 422 post_not_resolvable. To reply under a comment, pass parent_comment_urn (no post read then); a comment urn given here is a reply under that comment too. A post URL works when the id is in it: the feed permalink, the /posts/-activity-- share link, the -ugcPost-- share link. A link WITHOUT an id (a shortlink, a bare slug URL) is refused 422 entity_urn_not_resolvable: call enrich_linkedin_get_activity_urn_by_url first. The post does NOT need to be tracked or owned by us. Renamed from activity_urn on 2026-07-30; the old name is no longer accepted. text: type: string minLength: 1 maxLength: 1250 description: The comment body (caller-supplied, no templates or AI in-app). parent_comment_urn: type: string nullable: true maxLength: 512 description: >- Reply target: the comment URN to reply under. Omit or null for a top-level comment. mentions: type: array items: type: object properties: profile_id: type: string minLength: 1 description: >- Who to mention: a bare ACoA… profile id (as get-post-comments and the profile readers return) or the full urn:li:fsd_profile:. name: type: string minLength: 1 description: >- The exact substring of text that becomes the clickable link (usually the profile name). required: - profile_id - name description: >- Profile mentions (2026-08-21). Names are matched in text left to right in list order, each search starting after the previous mention. The node computes the character offsets itself. client_reference: type: string nullable: true maxLength: 255 description: >- Your key for this ONE comment (max 255, byte for byte): one key per comment, the same key on every repeat of it. The key and its place (the post as LinkedIn files it, named by any of its urns, or for a reply the comment it answers) are one comment whatever it says, and a repeat never goes out twice: it answers 200 with what the first send made (result.idempotent_replay, result.content_differs when this request says something else) or 409 naming error.context.send_outcome (in_flight, unknown with retry_after and send_decisive_at, or sent; not_sent with blocking_activity_log_sid when another comment in doubt holds the place). The same key at another place is another comment. Without a key the same words at the same place count as a repeat for an hour after they went out. check_linkedin_posting_sent asks by it. confirmed_not_sent: type: string nullable: true minLength: 18 maxLength: 18 pattern: ^ln_al_ description: >- A person's word that an earlier attempt of THIS send is not on LinkedIn: its activity_log_sid (ln_al_...), from the 409 or check_linkedin_posting_sent, given only after someone looked on LinkedIn. Taken once the attempt can no longer land (before that: 409 send_outcome_unknown, waiting_for may_still_land, retry_after and send_decisive_at that moment): it settles that attempt not_sent and this request goes out. Moot when the attempt is no longer in doubt; another send's sid is 422 not_this_message. confirmed_sent: type: string nullable: true minLength: 18 maxLength: 18 pattern: ^ln_al_ description: >- A person's word that an earlier attempt of THIS send IS on LinkedIn: its activity_log_sid, as for confirmed_not_sent (never both). Taken at once; it settles the attempt sent and sends nothing: the answer is 409 concurrent_send_in_flight with send_outcome sent while what it made is not known (LinkedIn is read for it), or 200 with it once a read has found it. Another send's sid is 422 not_this_message; an attempt already proved not sent is 409 confirmed_sent_contradicts. required: - linkedin_account_sid - entity_urn - text CreateLinkedinCommentResponse: 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: {} result: type: object properties: comment_urn: type: string description: The created comment ref. activity_log: type: object properties: {} description: >- Full dispatch row (linkedin-account-activity-log) per §4.12a. Poll it there by sid for the terminal outcome. idempotent_replay: type: boolean description: >- true when this answers a repeat (under the key, or without one the same words at the same place) with what the first send made: nothing was sent now. content_differs: type: boolean description: >- With idempotent_replay: true when this request's words (or a post's pictures or video) differ from those of the send that made it. required: - comment_urn - activity_log 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.