refactor: thread slackUserId through Slack bot createSession

[ColeMurray]

Summary

• Adds slackUserId parameter to createSession in the Slack bot
• Includes slack_user_id in structured log metadata for session creation
• The Slack user ID was already available at the call site (startSessionAndSendPrompt) but was not passed through to createSession
• No control plane changes — the value flows through logging only for now

Pre-step 5 of the unified user model migration (pre-steps doc). The main migration will add identity resolution (getUserInfo) and forward actor* fields through this same parameter path — having the user ID already threaded keeps that PR focused on identity logic.

Test plan

• npm run typecheck -w @open-inspect/slack-bot passes
• npm test -w @open-inspect/slack-bot — all 44 tests pass

Summary by CodeRabbit

• Chores
  • Enhanced Slack bot session handling to better track user information during session creation.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: ccbd45e0-198f-4eee-898b-33209ec0e362

📥 Commits

Reviewing files that changed from the base of the PR and between 4d37590 and 3b61e72.

📒 Files selected for processing (1)

• packages/slack-bot/src/index.ts

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📝 Walkthrough

Walkthrough

Extended the createSession() function to accept an optional slackUserId parameter, which is passed through to the control-plane request payload as slack_user_id. Updated the caller to provide the userId when invoking the function.

Changes

Cohort / File(s)	Summary
Slack Bot Session Enhancement packages/slack-bot/src/index.ts	Added optional slackUserId?: string parameter to createSession() and included it in the control-plane request payload as slack_user_id. Updated startSessionAndSendPrompt() to pass userId as the new parameter when calling createSession().

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~8 minutes

Possibly related PRs

• fix: exclude bot and automation sessions from analytics #499 — Modifies the same createSession() payload by adding spawnSource: "slack-bot", indicating parallel enhancements to session initialization.
• refactor(slack-bot): clean up branch preferences from #334 #421 — Updates the same call sites in packages/slack-bot/src/index.ts, specifically the createSession() argument handling.

Suggested reviewers

• open-inspect

Poem

🐰 A user ID hops along,
Through slack's bot channels, bright and strong,
Sessions now remember who,
With slack\_user\_id shining through! 🎉

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title accurately describes the main change: threading slackUserId through the createSession function in the Slack bot codebase.
Docstring Coverage	✅ Passed	Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

_{✏️ Tip: You can configure your own custom pre-merge checks in the settings.}

✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch pre-step-5/slack-thread-userId

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[github-actions]

Terraform Validation Results

Step	Status
Format	✅
Init	✅
Validate	✅

Note: Terraform plan was skipped because secrets are not configured. This is expected for external contributors. See docs/GETTING_STARTED.md for setup instructions.

Pushed by: @ColeMurray, Action: pull_request

[open-inspect]

Summary

PR Title and number: refactor: thread slackUserId through Slack bot createSession (#535)
Author: @ColeMurray
Files changed count: 1, additions/deletions: +5/-2

This change cleanly threads the Slack user ID into createSession and limits the behavioral impact to structured logging, matching the PR description. I reviewed the touched path for correctness, logging implications, and call-site consistency, and did not find blocking issues.

Critical Issues

• None.

Suggestions

• [Testing] packages/slack-bot/src/index.ts:891 - Consider adding an explicit assertion in src/index.test.ts that the session-creation log metadata includes slack_user_id, since that is the only behavioral change in this PR. The existing suite exercises the path, but a direct assertion would better protect this migration step from regression.

Nitpicks

• None.

Positive Feedback

• The parameter is threaded through the narrowest possible surface area, which keeps this pre-migration step focused.
• The control-plane request body is unchanged, avoiding accidental behavior changes outside logging.
• The existing Slack bot typecheck and test suite still pass against this branch, which reduces regression risk.

Questions

• None.

Verdict

• Approve: Ready to merge, no blocking issues.