Linear setup guide

Linear integration setup guide

This guide walks through setting up the ABCA Linear integration. Once configured, applying the bgagent label to an issue in a mapped Linear project triggers an autonomous task. The agent posts progress comments back on the Linear issue as it works.

Prerequisites

• ABCA CDK stack deployed (see Developer guide)
• A Cognito user account configured (see User guide)
• A Linear workspace where you have admin access (to create API keys and webhooks)
• AWS CLI configured with credentials for your ABCA account

How it works

1. A user adds the bgagent label (configurable per project) to a Linear issue.
2. Linear fires a webhook to POST /v1/linear/webhook. ABCA verifies the HMAC signature and dedups retries.
3. A processor Lambda resolves the Linear project → GitHub repo mapping and the Linear user → platform user mapping, then creates a task with channel_source: 'linear'.
4. The agent clones the repo, writes .mcp.json with Linear’s hosted MCP server, and runs. It uses mcp__linear-server__save_comment / mcp__linear-server__update_issue to post updates to the originating issue.
5. The agent opens a PR on GitHub and adds a final comment to the Linear issue with the PR link.

Authentication for v1 is a Linear personal API key. A single key powers all agent-to-Linear calls for the whole stack. OAuth bot install + multi-workspace is a v3 follow-up.

Trigger: only Linear issues with the configured label in a mapped project create tasks. Issues without the label, or in unmapped projects, are ignored. Label removal does not cancel a running task.

Step-by-step setup

Step 1: Generate a Linear personal API key

Open Linear Settings → Security, scroll to Personal API keys, and create one. Copy the token — it starts with lin_api_…. You won’t be able to see it again.

This key is used by the agent to post comments and update issue state. Personal API keys are full-workspace-scoped; document internally that you’re handing that authority to ABCA.

Step 2: Run the setup wizard

bgagent linear setup

The wizard prints the exact webhook URL for your deployment, then waits at a Webhook signing secret: prompt. Leave it running; go create the webhook in the next step, then return and paste both values.

Step 3: Create the Linear webhook

In Linear Settings → API, under Webhooks, click +:

• URL: paste the URL the wizard printed in Step 2.
• Resource types: check Issues only.
• Team: whichever team owns the projects you’ll map to ABCA (or all teams).
• Save, then open the webhook’s detail page and copy the signing secret.

Step 4: Finish the wizard

Back in your terminal at the paused bgagent linear setup prompt:

• Paste the webhook signing secret (from Step 3).
• Paste the personal API key (from Step 1).

Both are stored in Secrets Manager (LinearWebhookSecret and LinearApiTokenSecret). The wizard validates that the personal API key starts with lin_api_. Full authentication is verified the first time a webhook arrives or the agent calls the Linear MCP.

As a final step, setup calls the Linear API with the token you just stored, looks up the token owner, and auto-links that Linear identity to the Cognito user currently logged in to the CLI. This skips the code-exchange ceremony for the common case where one person installs ABCA for their own workspace. If the auto-link fails (token invalid, not logged in, etc.) setup prints a warning and continues — you can always fall back to the manual link flow in Step 6.

Step 5: Onboard a Linear project

Map a Linear project UUID to the GitHub repo you want tasks routed to:

bgagent linear onboard-project <linear-project-id> --repo owner/repo

Optional flags:

Flag	Purpose	Default
--label <label>	Linear label that triggers a task	bgagent
--team-id <id>	Linear team UUID (stored for debug only)	—
--region <region>	AWS region	from bgagent configure
--stack-name <name>	CloudFormation stack name	backgroundagent-dev

Finding the Linear project UUID. Linear’s project URL (https://linear.app/<workspace>/project/<slug>-<short>) contains a truncated UUID at the end — that’s not the full UUID the webhook sends. List the full UUIDs for all projects visible to the stored API token:

bgagent linear list-projects

Copy the id of the project you want to onboard. onboard-project validates the UUID format and will reject the truncated slug version with a pointer back to this command.

Step 6: Link your Linear account

ABCA needs to know which platform user a Linear actor maps to so tasks are attributed correctly.

The token owner is linked automatically. bgagent linear setup calls Linear’s viewer query with the token you just pasted and writes the mapping for the Cognito user running the CLI. Look for ✓ Linked Linear user … in the setup output — if you saw that, you’re done. Skip to Step 7.

Linking additional Linear users (anyone other than the API-token owner) isn’t supported in v1. A comment-triggered flow (bgagent link in a Linear comment → receive code → bgagent linear link <code>) is a planned follow-up; the bgagent linear link <code> CLI command exists today but no Linear-side code generator ships with it yet.

For v1, design the flow around the API-token owner: that person installs ABCA, runs bgagent linear setup, and submits tasks on their own behalf. Tasks triggered by other Linear users in the workspace will be dropped by the processor with "Linear actor has no linked platform user — skipping task creation".

Step 7: Test it

Add the bgagent label to a Linear issue in a mapped project. Within a few seconds:

• The Linear webhook Lambda logs an INFO entry and invokes the processor.
• The processor creates a task in the TaskTable with channel_source: 'linear'.
• The agent container starts, clones the repo, and posts a 🤖 Starting on this issue… comment to the Linear issue.
• When the agent opens a PR, another comment appears with the PR link and the issue transitions to In Review (if that state exists).
• On completion or failure, a final status comment is posted.

Usage

Trigger a task

Add the bgagent label (or whatever you configured) to an issue in a mapped Linear project. The issue title + description becomes the task description.

Check status

• From Linear: the issue itself — progress comments are posted as the agent works.
• From the CLI: bgagent list / bgagent status <task-id>.

Cancel a task

Use bgagent cancel <task-id>. Removing the Linear label does not cancel a running task.

Troubleshooting

Webhook doesn’t trigger a task

1. Is the project mapped? Run aws dynamodb scan --table-name <LinearProjectMappingTableName> (look up the table name via aws cloudformation describe-stacks).
2. Is the label spelled exactly as configured? Match is case-insensitive but must be the same word.
3. Check CloudWatch logs for the WebhookFn and WebhookProcessorFn Lambdas for Invalid Linear webhook signature, Linear project is not onboarded, or Linear actor has no linked platform user.

”Linear actor has no linked platform user — skipping task creation”

The Linear user who applied the label hasn’t linked their account. Run bgagent linear link <code>.

”Invalid or expired link code”

Link codes expire in 10 minutes. Generate a new one.

Agent doesn’t post comments to Linear

1. Verify the API token is stored: aws secretsmanager get-secret-value --secret-id <LinearApiTokenSecretArn> (admin-only).
2. Check the agent container logs for Linear MCP configured at … — absence means channel_source wasn’t set on the task.
3. Check for ${LINEAR_API_TOKEN} in the MCP handshake — if unresolved, the token secret wasn’t piped into the container. Re-deploy.

Webhook signature verification fails repeatedly

The signing secret in Secrets Manager doesn’t match the webhook. Re-run bgagent linear setup and paste the secret from the webhook’s detail page (not the API key page).

Limits and budgets

Linear’s API rate limits (personal API key, per user):

Metric	Limit / hour
Requests	5,000
Complexity points	3,000,000

A typical task makes ~10 Linear API calls (one starting comment, one PR comment, one state transition, one final comment), nowhere near the ceiling. Heavy users should monitor the X-RateLimit-Requests-Remaining header in agent logs.

What’s out of scope in v1

• Attachments: v1 tickets are text-only. Linear attachments (mockups, screenshots) are planned for v1.1 via S3 pre-fetch.
• OAuth bot install: v1 uses a single personal API key. OAuth + multi-workspace is v3.
• Comment-driven triggers: only labels trigger tasks. Comment commands are v2+.
• Per-issue status polling: use bgagent status or watch the Linear issue comments.

Removing the integration

Deactivate a project mapping:

# manual DynamoDB update — no CLI for this yet
aws dynamodb update-item \
  --table-name <LinearProjectMappingTableName> \
  --key '{"linear_project_id":{"S":"<uuid>"}}' \
  --update-expression 'SET #s = :removed' \
  --expression-attribute-names '{"#s":"status"}' \
  --expression-attribute-values '{":removed":{"S":"removed"}}'

Delete the Linear webhook from Linear Settings → API.

To remove the Linear integration from your ABCA deployment entirely, delete the webhook in Linear, delete the LinearIntegration construct from the stack, and redeploy.