docs(screenshots): add USER_GUIDE / COST_MODEL / ROADMAP coverage

Closes the doc gaps from the screenshot feature followup list:

- USER_GUIDE.md: new 'Preview-deploy screenshots (optional)' subsection
  under Notifications, points at DEPLOY_PREVIEW_SCREENSHOTS_GUIDE.md.
- COST_MODEL.md: 'Optional: deploy-preview screenshots' table covering
  AgentCore Browser session, Lambda processor, S3, CloudFront line items
  (~$0.01 per screenshot, dominated by Browser session time).
- ROADMAP.md: marks the feature shipped under Notification plane with a
  one-line description of the trigger model and post-deploy latency.

Mirrors regenerated via docs/scripts/sync-starlight.mjs.

Author: isadeks

docs/design/COST_MODEL.md

@@ -47,6 +47,22 @@ Assuming a typical task: 1–2 hours, Claude Sonnet, ~100K input tokens, ~20K ou
 | Custom step Lambdas | $0–0.05 | Only if configured. Per-invocation: ~$0.01 per step. |
 | **Total per task** | **$2–15** | Bedrock tokens dominate (>90% of per-task cost). New interactive features add <$0.01 per task. |
 
+### Optional: deploy-preview screenshots
+
+The screenshot pipeline (see [Deploy preview screenshots guide](../guides/DEPLOY_PREVIEW_SCREENSHOTS_GUIDE.md)) is opt-in per repo and deterministic — no LLM, no agent runtime. Only fires when a connected deploy provider posts `deployment_status: success`.
+
+| Component | Estimated cost per screenshot | Notes |
+|---|---|---|
+| AgentCore Browser session | $0.005–0.015 | ~30–60 s of `aws.browser.v1` for navigate + capture. Per-second billing. |
+| Lambda processor | <$0.001 | 512 MB, ~10–20 s wall time per invocation. |
+| S3 PutObject + storage | <$0.001 | One PNG (~200 KB–2 MB), 30-day TTL via lifecycle. |
+| CloudFront request + bytes-out | <$0.001 | First-render fetch from GitHub markdown image proxy + a small number of viewer fetches. |
+| **Total per screenshot** | **~$0.01** | Dominated by AgentCore Browser session time. |
+
+Baseline overhead (CloudFront distribution + S3 bucket idle) is <$1/month and absorbed into the existing infrastructure baseline above. CloudFront has no per-distribution monthly fee; you pay only per-request and per-byte-out.
+
+A high-volume team with ~500 preview deploys per month would add ~$5/month to the per-task variable line, which is rounding error compared to Bedrock token costs.
+
 ### Cost sensitivity analysis
 
 | Factor | Impact on cost | Mitigation |

docs/guides/ROADMAP.md

@@ -76,6 +76,7 @@ What's shipped and what's coming next.
 - [x] **GitHub edit-in-place** - Single status comment per task on the target PR, edited in place as progress events fire (phase, milestone, cost, link)
 - [x] **Routable agent milestones** - Named checkpoints (`pr_created`, `nudge_acknowledged`) unwrapped against allowlist for channel filter matching
 - [x] **Slack notification dispatcher** - FanOut Block Kit messages for Slack-origin tasks (lifecycle events, threaded replies, terminal dedup, in-thread cancel). Generic fallback text for unmapped event types (e.g. some milestones); richer milestone and approval-gate rendering is follow-up work
+- [x] **Deploy-preview screenshots** - Listens for GitHub `deployment_status: success` events from any provider (Vercel, Amplify Hosting, Netlify, GitHub Actions); captures the preview URL via AgentCore Browser; posts a markdown image comment on the open PR (and on the linked Linear issue if Linear is configured). Lambda-only, deterministic, ~10–15 s post-deploy. See [Deploy preview screenshots guide](./DEPLOY_PREVIEW_SCREENSHOTS_GUIDE.md).
 - [ ] **Email dispatcher** - Log-only stub; pending SES integration
 
 ### Channels

docs/guides/USER_GUIDE.md

@@ -1014,6 +1014,14 @@ The notification plane uses DynamoDB Streams to fan out task events to channel-s
 
 The status comment shows: current phase, last milestone, cost so far, and a link to the task. It updates on key events (`session_started`, `pr_created`, `task_completed`, `task_failed`, `nudge_acknowledged`, and routable agent milestones).
 
+### Preview-deploy screenshots (optional)
+
+If your repo is wired to a deploy provider that publishes GitHub `deployment_status` events (Vercel, Amplify Hosting, Netlify, GitHub Actions custom CD, etc.), ABCA can capture a full-page screenshot of each preview URL and post it as an image comment on the open PR — and on the linked Linear issue if Linear is configured.
+
+This runs independently of the agent: there's no LLM involved, just a Lambda that drives a headless browser via AgentCore Browser. End-to-end latency is typically 10–15 seconds after the deploy provider reports success.
+
+Setup is opt-in and per-repo. See the [Deploy preview screenshots guide](./DEPLOY_PREVIEW_SCREENSHOTS_GUIDE.md) for the wiring (one webhook on the repo, one secret pasted into AWS).
+
 ## What the agent does
 
 The agent is the part of the platform that actually writes code. When the orchestrator finishes preparing a task (admission, context hydration, pre-flight checks), it hands off to an agent running inside an isolated compute environment. Today the platform supports **Amazon Bedrock AgentCore Runtime** as the default compute backend - each agent session runs in a Firecracker MicroVM with session-scoped storage and automatic cleanup. The architecture is designed to support additional compute backends (ECS on Fargate, ECS on EC2) for repositories that need more resources or custom toolchains beyond the AgentCore 2 GB image limit. See the [Compute design](/sample-autonomous-cloud-coding-agents/architecture/compute) for the full comparison.

docs/src/content/docs/architecture/Cost-model.md

@@ -51,6 +51,22 @@ Assuming a typical task: 1–2 hours, Claude Sonnet, ~100K input tokens, ~20K ou
 | Custom step Lambdas | $0–0.05 | Only if configured. Per-invocation: ~$0.01 per step. |
 | **Total per task** | **$2–15** | Bedrock tokens dominate (>90% of per-task cost). New interactive features add <$0.01 per task. |
 
+### Optional: deploy-preview screenshots
+
+The screenshot pipeline (see [Deploy preview screenshots guide](/using/deploy-preview-screenshots-guide)) is opt-in per repo and deterministic — no LLM, no agent runtime. Only fires when a connected deploy provider posts `deployment_status: success`.
+
+| Component | Estimated cost per screenshot | Notes |
+|---|---|---|
+| AgentCore Browser session | $0.005–0.015 | ~30–60 s of `aws.browser.v1` for navigate + capture. Per-second billing. |
+| Lambda processor | <$0.001 | 512 MB, ~10–20 s wall time per invocation. |
+| S3 PutObject + storage | <$0.001 | One PNG (~200 KB–2 MB), 30-day TTL via lifecycle. |
+| CloudFront request + bytes-out | <$0.001 | First-render fetch from GitHub markdown image proxy + a small number of viewer fetches. |
+| **Total per screenshot** | **~$0.01** | Dominated by AgentCore Browser session time. |
+
+Baseline overhead (CloudFront distribution + S3 bucket idle) is <$1/month and absorbed into the existing infrastructure baseline above. CloudFront has no per-distribution monthly fee; you pay only per-request and per-byte-out.
+
+A high-volume team with ~500 preview deploys per month would add ~$5/month to the per-task variable line, which is rounding error compared to Bedrock token costs.
+
 ### Cost sensitivity analysis
 
 | Factor | Impact on cost | Mitigation |

docs/src/content/docs/roadmap/Roadmap.md

@@ -101,4 +101,12 @@ When a task targets a pull request (`pr_iteration` or `pr_review`), the platform
 
 The notification plane uses DynamoDB Streams to fan out task events to channel-specific dispatchers. Currently the GitHub edit-in-place dispatcher is active; Slack and Email dispatchers are planned.
 
-The status comment shows: current phase, last milestone, cost so far, and a link to the task. It updates on key events (`session_started`, `pr_created`, `task_completed`, `task_failed`, `nudge_acknowledged`, and routable agent milestones).
+The status comment shows: current phase, last milestone, cost so far, and a link to the task. It updates on key events (`session_started`, `pr_created`, `task_completed`, `task_failed`, `nudge_acknowledged`, and routable agent milestones).
+
+### Preview-deploy screenshots (optional)
+
+If your repo is wired to a deploy provider that publishes GitHub `deployment_status` events (Vercel, Amplify Hosting, Netlify, GitHub Actions custom CD, etc.), ABCA can capture a full-page screenshot of each preview URL and post it as an image comment on the open PR — and on the linked Linear issue if Linear is configured.
+
+This runs independently of the agent: there's no LLM involved, just a Lambda that drives a headless browser via AgentCore Browser. End-to-end latency is typically 10–15 seconds after the deploy provider reports success.
+
+Setup is opt-in and per-repo. See the [Deploy preview screenshots guide](/using/deploy-preview-screenshots-guide) for the wiring (one webhook on the repo, one secret pasted into AWS).