# Session Start > Start a Polygraph Session - Skill: `nrwl/session-start` (Agent Skill) - Install (CLI): `npx skillmds@latest add nrwl/session-start` - Raw SKILL.md: https://api.skillmd.com/api/skills/nrwl/session-start/raw - Safety review: pending - Works with: Claude Code, Claude.ai, OpenAI Codex - Category: Coding & Dev Tools - Author: nrwl (https://skillmd.com/u/nrwl) - Updated: 2026-09-17 - Page: https://skillmd.com/skills/nrwl/session-start --- # Start a Polygraph Session Start or reconnect a Polygraph session so the current work has shared, resumable context: session URL, repository graph visibility, linked PR/CI state, and the option to expand across repository boundaries when needed. {% if platform == "codex" %} ## Codex Routing Rule Use Codex `spawn_agent` with `agent_type: "polygraph-init-subagent"` for session creation or repository discovery. Do NOT call the Polygraph MCP `list_repos` or `start_session` tools directly from the parent conversation. Direct `add_repo` is allowed only when the user gives exact repository refs for an existing session. Do NOT pass `fork_context: true` to Codex `spawn_agent` when `agent_type` is a custom agent. {% endif %} ## Check Authentication First Before session work, the parent conversation must check Polygraph auth with `whoami` or `polygraph whoami`. - If auth is valid and an organization is selected, continue. - If auth is missing, expired, or no organization is selected, stop session work. Do not keep trying session creation or discovery. - Facilitate user reauth through the browser-based flow, such as `polygraph auth login` or the MCP `login` equivalent. After login, make sure an organization is selected with `polygraph account select` or the MCP equivalent when needed. - Re-run `whoami` after reauth. Continue only after it confirms a valid login and selected organization. Do not breeze past auth failures. In Codex Desktop, auth recovery usually requires the user to complete the browser login flow; surface that clearly and wait for it before continuing. ## Parent Session Detection The parent conversation is responsible for detecting an existing Polygraph session ID from the current context, startup banner, or user-provided session URL/ID, then passing that `sessionId` explicitly to `polygraph-init-subagent` when launching it. The init subagent cannot infer the parent's current session context by itself. For a fresh Codex Desktop conversation started with `/polygraph:session-start`, no `sessionId` is expected. Launch `polygraph-init-subagent` without `sessionId` so it creates a new session. ## Decide the Session Path Pick one path before using tools. 1. **Existing session with repos** - If a Polygraph session ID is already in scope and the user did not ask to add repositories, pick by intent: to continue the session's work from this conversation, join it via `resume_session`; to only inspect it, call `show_session` and print the session details. Do not create a new session. 2. **Existing session, adding exact repository refs** - If a session ID is in scope and the user provided exact refs by ID, short name, full name, GitHub `owner/repo` slug, URL-like slug, or MCP resource syntax, call `add_repo(sessionId, repoIds: [...])` directly. Do not run discovery. 3. **Existing session, discovery needed** - If a session ID is in scope but repos need to be discovered or selected, launch `polygraph-init-subagent` with the existing `sessionId` and `userContext`. The subagent must use `add_repo`, not `start_session`. 4. **No session in scope** - Launch `polygraph-init-subagent` with `userContext` and no `sessionId`. The subagent will discover related repositories when needed and call `start_session`. Exact refs are not limited to organization repos. Public open-source repos can be added by `owner/repo` slug or URL even if they do not appear in repository discovery. {% if platform == "codex" %} ## Launch the Init Subagent Use this shape when discovery or new-session creation is needed: {% raw %} ``` spawn_agent( agent_type: "polygraph-init-subagent", message: """ Parameters: - sessionId: "" - userContext: "" The parent conversation detected any existing sessionId from current context, startup banner, or user-provided session URL/ID and passed it explicitly here. The init subagent cannot infer parent session context by itself. If sessionId is provided, reuse that session and use add_repo to attach repositories -- do NOT call start_session. If exact repo refs were provided, pass them directly to add_repo and do NOT call list_repos. If discovery is needed, discover candidates and select relevant repos. If sessionId is omitted, this is a fresh session-start flow; create a new session via start_session. Return a structured summary. """ ) ``` {% endraw %} Omit the `sessionId` line when creating a new session. Include it when attaching discovered repos to an existing session. Collect the result with `wait_agent` when the main flow needs the session before proceeding. {% elsif platform == "claude" %} Launch the plugin-namespaced `polygraph:polygraph-init-subagent` Task for discovery or new-session creation. Use direct `add_repo` only for exact refs on an existing session. {% elsif platform == "opencode" %} Invoke `@polygraph-init-subagent` for discovery or new-session creation. Use direct `add_repo` only for exact refs on an existing session. {% else %} If there is no subagent mechanism, use `list_repos` only when discovery is needed, then call `start_session` for a new session or `add_repo` for an existing session. {% endif %} ## Print the Result When a brand-new session is created, render the session welcome card. Prefer the `session_intro` MCP tool when available; otherwise run `polygraph session intro -s ` and print the returned markdown verbatim. For an existing or reconnected session, print: **Session:** POLYGRAPH_SESSION_URL **Repositories in this session:** - REPO_FULL_NAME Use `polygraphSessionUrl` from the session response for `POLYGRAPH_SESSION_URL`, and use repository entries from the session response for `REPO_FULL_NAME`.