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Merge branch 'main' into perf/vom-hover-probe-opt-in

Browse Source 
main rewrote SKILL.md into a leaner core (#167) while this branch documented
the opt-in --probe-hover flag against the old structure. Keep main's rewritten
prose and re-apply the probe-hover guidance on top of it: the [has-submenu] /
[expanded] markers, when reaching for --probe-hover is warranted, and its slot
in the page-reading escalation ladder ahead of get-html/screenshot.

Co-authored-by: Cursor <cursoragent@cursor.com>
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drakezhang
2026-09-02 12:18:06 +08:00
co-authored by Cursor
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---
name: browser-skill
description: |
Use when the user asks to perform browser automation tasks against their
logged-in browser: visit and read pages, fill forms, scrape data, click
through a flow, regression-test a PR's UI, validate a deployed page.
Requires the bsk CLI installed and the browser-skill extension loaded.
Use when the user asks to automate their logged-in Chromium browser: visit
and read pages, fill forms, scrape data, click through flows, regression-test
a PR's UI, validate a deployed page, or operate a tab they identify. Requires
the bsk CLI and browser extension.
---
# browser-skill
Drive the user's **real Chromium browser** (with their logins and cookies) through the `bsk` CLI. The extension opens an isolated **Agent Window** for automation; the user's normal windows stay protected unless you explicitly borrow a tab.
Drive the user's real Chromium browser through `bsk`. Automation runs in an isolated **Agent
Window** with the user's existing logins and cookies. User-window tabs remain protected unless they
are explicitly borrowed.
## When to use
Do not use this skill for tasks with no browser, for extension installation, or when the user only
wants instructions. Never extract credentials, cookies, tokens, or other secrets from pages.
- Open pages, read titles/text, scrape structured data from sites the user can already access
- Fill forms, click through multi-step flows, smoke-test a UI change
- Understand pages with `bsk snapshot` first; use `bsk get-html` or `bsk screenshot` only when the snapshot is insufficient
- Operate on a specific user tab they point you at (after `bsk tab borrow`)
## Required lifecycle
## When NOT to use
Every browser task owns a bounded session:
- Tasks with **no browser** involved (files, APIs, databases only)
- Installing or configuring the extension (point the user to setup docs instead)
- **Credential harvesting** — never run `bsk evaluate` on banking, SSO, or password-manager pages to extract tokens, cookies, or secrets
- Long-lived control of a user's personal login window — borrow only for the immediate step, then `bsk tab return` or end the session
- Replacing the user's manual browsing when they only wanted an explanation
## Prerequisites
1. `bsk` on `PATH` (Rust CLI from browser-skill)
2. browser-skill **extension** loaded in Chromium and connected (popup shows green, or an upgrade reminder — still connected; continue)
3. Any `bsk` command auto-starts background services as needed; use `bsk doctor` if anything fails
## Mandatory workflow
Every automation task **must** follow this lifecycle. Do **not** rely on idle timeouts (default session idle is 5 minutes).
```
1. bsk session start → capture the 4-letter session id printed on stdout
2. … every tool command … → always pass --session <id>
3. bsk session stop <id> → REQUIRED when done (even on error paths)
```text
1. bsk session start # retain the printed 4-letter session id
2. bsk ... --session <id> # pass it to every session-scoped command
3. bsk session stop <id> # always run on success and error paths
```
Optional: `bsk session start --browser <instance-id-or-label>` when multiple browsers are connected (`bsk browsers` / error output lists them). Add `--no-focus` to open the Agent Window in the background without stealing focus from the user's current window.
Do not rely on the idle timeout for cleanup. Stop the session as soon as the goal is met unless the
user explicitly asks to keep it open. Stopping also returns borrowed tabs.
Emergency cleanup: `bsk session stop --all` or the Agent Window overlay **Stop all**.
Any `bsk` command auto-starts the background services it needs; never manage the daemon by hand.
When multiple browsers are connected, use `bsk browsers` and start with
`bsk session start --browser <id-or-label>`. Add `--no-focus` to that same start command when the
Agent Window does not need to interrupt the user's current work; it is not a flag on other commands.
Run `bsk doctor` when startup or transport problems persist after one retry.
## Stop when the goal is met
## Work toward one observable goal
Every task is a **bounded goal**, not open-ended browsing. The goal may come from the user's request, a recorded `trace.json`, or both.
- Derive a concrete success condition from the user's request or a supplied trace.
- Take the shortest purposeful path: observe, act, then make at most one observation to confirm an
ambiguous result.
- Once success is visible, do not click, refresh, navigate, switch tabs, or perform extra checks.
- If a human-only step appears or two attempts make no progress, request help instead of
brute-forcing.
1. **Define success first** — one concrete, observable condition derived from the user's words, `purpose`, or the last meaningful step in a trace (e.g. "form submitted", "item added to cart", "playback started").
2. **Take the shortest path** — snapshot → act → at most one check. Do not wander, re-try unrelated actions, or stack exploratory steps.
3. **Stop as soon as success is reached** — run `bsk session stop <id>` immediately unless the user explicitly asked to keep the session open (e.g. "don't close yet", "keep browsing").
4. **No post-success work** — once the goal is met, do not click, refresh, navigate, re-search, switch tabs, or "double-check" that it worked. Further verification is a new task.
5. **When blocked, pause — do not brute-force** — if the page requires human input (login, captcha, OTP, payment confirmation) or an action fails twice with no progress, call `bsk request-help` instead of retrying blindly. See **Ask the human for help** below.
6. **When unsure** — at most one extra `bsk snapshot`. If success looks met, stop. If not, ask the user; do not keep clicking.
With a trace, follow its semantic target information and values in order, but treat its refs as
record-local hints. Stop when its purpose or last meaningful effect is satisfied. A trace guides the
task; it does not expand the user's goal or authorize additional actions.
**With a trace:** replay steps in order using `target` role/name/tag and raw `value`/`selection` fields. After the last step (or when its `effect.navigated_to` / success hint is satisfied), apply rules 3–4 immediately. The trace guides execution; it does not extend control beyond the goal.
## Observe, act, observe
**Without a trace:** the user's request *is* the success condition. Satisfying it ends the task — same stop rules apply.
Use this default loop:
## Core interaction loop
Write operations only affect tabs in the **Agent Window** (or tabs you **borrowed** into it).
```
```text
bsk navigate <url> --session <id>
bsk observe --session <id> → primary semantic VOM view
bsk snapshot --session <id> → static aria tree fallback when VOM is insufficient
bsk hover @e3 --session <id> → reveal hover-triggered menus before re-observing/clicking
bsk click @e4 --session <id> → or bsk fill, bsk select, bsk press
bsk observe --session <id> → again after navigation / DOM change
bsk observe --session <id>
bsk click|hover|fill|select|press ... --session <id>
bsk observe --session <id> # after navigation or a meaningful DOM change
```
**Refs invalidate after navigation** — always re-snapshot before clicking, filling, or selecting on a new page.
Prefer fresh `@eN` refs over CSS selectors. Navigation invalidates refs; large DOM changes may also
make them stale. Observe again before the next interaction.
Prefer `@eN` refs from the latest snapshot over raw CSS selectors. Use `--ref` / `--selector` when ambiguous (`bsk click --help`).
An observation marks a hover-only surface as `@e1 button "Products" [hover first: Shoes | Bags]`.
The listed items are labels, not usable refs: hover the trigger, observe again, then act on the
revealed item's own ref. Do not click the trigger itself unless the user wants the trigger's action.
`[has-submenu]` and `[expanded]` mark the same kind of trigger without listing what it hides.
When VOM marks a control `[has-submenu]` or `[expanded]`, its menu items are not in the observation yet. Run `bsk hover <that-ref> --session <id>`, then immediately run `bsk snapshot` or `bsk observe` again and click the newly visible menu item ref. Do not click the trigger itself unless the user explicitly wants the trigger action. `[hover first: …]` means the same thing and additionally lists what that trigger revealed.
`bsk observe` does not hover the page on its own. Reach for `--probe-hover` when a control you have
good reason to expect is absent **and** no marker points at a trigger — that combination is what a
CSS-only hover menu looks like from here. It hovers a bounded set of likely triggers, so it costs a
few seconds and touches the live page; once you know which element hides the menu, `bsk hover <ref>`
is cheaper and more precise.
`bsk observe` does not hover the page on its own. Reach for `--probe-hover` when a control you have good reason to expect is absent from the observation **and** no `[has-submenu]` marker points at a trigger — that combination is what a CSS-only hover menu looks like from here. Try it before falling back to `bsk get-html` or `bsk screenshot`. It hovers a bounded set of likely triggers to surface hover-only menus and tooltips; it costs a few seconds and touches the live page, so once you know which element hides the menu, `bsk hover <ref>` is cheaper and more precise.
Escalate page reading only as needed:
## Observation priority
1. `bsk observe` for normal semantic understanding, text, controls, and refs.
2. `bsk observe --probe-hover` once when an expected control is missing and no marker points at a
trigger.
3. `bsk snapshot` when a stricter static accessibility tree is more useful.
4. `bsk get-html` for exact markup or hidden metadata that semantic views cannot provide.
5. `bsk screenshot` for layout, styling, canvas, images, or requested visual evidence.
Start with `bsk observe` to understand page structure, text, controls, and element refs. Use `bsk snapshot` only when you need the stricter static accessibility tree or VOM is insufficient. Only escalate to raw HTML or screenshots when the latest observation cannot answer the question:
Do not start with raw HTML or screenshots merely to discover ordinary controls. When interaction is
needed, obtain a fresh observation before acting on screenshot or HTML findings.
1. `bsk observe` — primary semantic VOM observation
2. `bsk observe --probe-hover` — re-run once when an expected control is missing and nothing marks a hover trigger
3. `bsk snapshot` — strict static accessibility tree fallback
4. `bsk get-html` — when hidden DOM, metadata, or markup details are required
5. `bsk screenshot` — when visual layout, canvas/image content, or styling cannot be inferred from the observation. Use `--ref @eN` (from the latest snapshot/observe) to crop to one element; omit `--ref` for the full visible tab.
## Respect the Agent Window boundary
Do **not** call `bsk get-html` or `bsk screenshot` first just to inspect a page.
Normal page writes affect only Agent Window tabs. To operate a user tab, first list it with
`bsk tab list --scope user --session <id>`, then `bsk tab borrow <tab-id>`. Return it immediately
after the relevant step with `bsk tab return <tab-id>`; never invent a tab id or keep a personal tab
borrowed across unrelated work.
## Sandbox rules
## Ask the human when needed
| Rule | Detail |
|------|--------|
| Agent Window | `bsk tab create`, `bsk navigate`, `bsk click`, etc. work on agent tabs by default |
| User tabs | Read-only until borrowed: `bsk tab list --session <id> --scope user` then `bsk tab borrow <tab-id> --session <id>` |
| Return borrowed tabs | Call `bsk tab return <tab-id> --session <id>` when finished; unreturned tabs are **auto-returned** on `bsk session stop` |
| Writes off-agent | Commands that mutate the page fail if the tab is not in the Agent Window — borrow or create a tab first |
Use `bsk request-help` for login, captcha, OTP, payment confirmation, consent, or another step the
user must complete. Give a precise prompt and pass fresh `--target` refs/selectors when concrete
controls can be highlighted. Use completion criteria only when the page has a clear stable success
signal.
## Global flags
The result `outcome` is one of `continued`, `completed`, `cancelled`, `timed_out`, or `disabled`
(`navigated` is deprecated — never treat navigation as a completion signal). Resume only after
`continued` or `completed`. Treat `cancelled` as rejection, and `timed_out` or `disabled` as a
blocker rather than a reason to retry. After control returns, run a fresh `bsk observe` before
reasoning about the page or using refs.
| Flag | Purpose |
|------|---------|
| `--json` | Machine-readable JSON on stdout (errors too) |
| `--quiet` | Suppress informational stderr |
| `-v` / `-vv` | More verbose logging |
## Command inventory
Auto-update is **on by default** — the background daemon upgrades `bsk` itself when a new release is available (postponed while a session is active). Set `BSK_AUTO_UPDATE=off` to disable it and upgrade manually with `bsk update`.
This list of names is complete. Never invent a command outside it; read
`bsk <command...> --help` for flags instead of guessing them.
Command-specific flags (timeouts, `--tab-id`, `--wait-until`, …): **`bsk <cmd> --help`**
## CLI command reference (one line each)
Details and flags: **`bsk <cmd> --help`**
### Diagnostics
| Command | Summary |
|---------|---------|
| `bsk status` | Connection health, connected browsers, active sessions |
| `bsk doctor` | Deep diagnostics and repair hints |
| `bsk browsers` | List connected browser instances (ids, labels, versions) |
### Session
| Command | Summary |
|---------|---------|
| `bsk session start` | Open Agent Window (`--width`/`--height` for initial size); prints **4-letter session id** |
| `bsk session start --no-focus` | Open Agent Window in the background without stealing focus |
| `bsk session stop <id>` | End session, close Agent Window, auto-return borrowed tabs |
| `bsk session stop --all` | Stop every active session |
| `bsk session list` | List active sessions |
### Window (require `--session <id>`)
| Command | Summary |
|---------|---------|
| `bsk window resize` | Resize the Agent Window (`--width`, `--height`; 100..=7680 CSS px) |
### Device emulation — `bsk emulate` (requires `--session <id>`)
Emulate a mobile device environment on the agent tab via CDP — viewport, User-Agent, and touch — to debug a page's mobile layout and behaviour:
```bash
bsk emulate --session <id> --device iphone-14
bsk emulate --session <id> --width 390 --height 844 --dpr 3 --mobile --ua "Mozilla/5.0 (iPhone…" --touch
bsk emulate --session <id> --off
```text
session start|stop|list browsers status doctor update logs
navigate navigate-back navigate-forward reload wait-for-navigation wait-ms
observe snapshot get-html screenshot console network
click hover fill select press evaluate
tab list|create|close|select|borrow|return window resize emulate
request-help record start|stop
```
- Presets (`--device`): `iphone-14`, `iphone-14-pro-max`, `iphone-se`, `pixel-7`, `galaxy-s23`, `ipad-mini`, `galaxy-tab-s8`. Manual flags (`--width`/`--height`/`--dpr`/`--mobile`/`--ua`/`--accept-language`/`--touch`/`--max-touch-points`) also work without a preset, or override individual preset fields; `--no-mobile`/`--no-touch` turn a preset's mobile viewport / touch emulation back off.
- Repeated runs merge field by field onto the tab's current emulation state — only the flags you pass change. E.g. after `--device iphone-14`, `bsk emulate --session <id> --width 390 --height 844` keeps the preset's dpr (`3`) and mobile viewport. (The extension remembers the state per tab; after an extension reload the next run applies only the fields it carries.)
- `--off` clears every override (viewport, UA, touch) and the remembered state, restoring the tab's real environment.
- Scope: overrides apply to **one tab only** (CDP per-target) and are **not inherited by new tabs** — re-run `bsk emulate` after opening or switching to another tab (default target is the session's active tab; `--tab-id` overrides).
- Emulation covers viewport/UA/touch only; it does not throttle the network, fake geolocation, or synthesise real touch-event streams.
Required flags that are easy to get wrong:
### Tabs (require `--session <id>`)
| Command | Summary |
|---------|---------|
| `bsk tab list` | List tabs (`--scope user\|agent\|all`, default `all`) |
| `bsk tab create` | New tab in Agent Window (`--url`, `--no-active`, `--index`) |
| `bsk tab close <tab-id>` | Close an agent tab |
| `bsk tab select <tab-id>` | Focus an agent tab |
| `bsk tab borrow <tab-id>` | Move a user tab into the Agent Window |
| `bsk tab return <tab-id>` | Return a borrowed tab to its original window |
### Observation (require `--session` unless noted)
| Command | Summary |
|---------|---------|
| `bsk snapshot` | First-choice static page understanding: accessibility tree with `@eN` element refs |
| `bsk observe` | Semantic VOM observation; `--probe-hover` adds bounded active hover probing for conditional surfaces |
| `bsk get-html` | Raw HTML dump after snapshot is insufficient (high token cost) |
| `bsk screenshot` | PNG capture after snapshot is insufficient: full visible tab, or `--ref @eN` to crop to one element (`--out` path optional) |
### Console & network debugging (read-only; require `--session`)
| Command | Summary |
|---------|---------|
| `bsk console` | Buffered page console messages, JS exceptions, and browser log entries (`--include-stack` for stack traces) |
| `bsk network` | Buffered network responses (status, method, URL, MIME/resource type) and failures (`net::ERR_*` reason) |
Both capture from the moment the tab is attached and read a bounded per-tab buffer: `--since <seq>` pages from a cursor (`next_since` in the result), `--limit` (default 50, max 200), `--max-text-chars` (default 1000, max 4096), `--tab-id` to target a non-active tab. Both are strictly read-only — they never intercept or modify traffic, and request/response headers, bodies, and timings are not captured.
### Navigation
| Command | Summary |
|---------|---------|
| `bsk navigate <url>` | Go to URL in agent tab (`--wait-until`, `--timeout`) |
| `bsk navigate-back` | History back one step |
| `bsk navigate-forward` | History forward one step |
| `bsk reload` | Reload current tab (`--hard` bypass cache) |
(`bsk navigate back` / `bsk navigate forward` are equivalent subcommands.)
### Interaction
| Command | Summary |
|---------|---------|
| `bsk click <ref-or-selector>` | Click element (`--button`, `--click-count`, `--modifiers`) |
| `bsk hover <ref-or-selector>` | Move the mouse to an element and wait for hover UI to settle (`--settle`, `--modifiers`) |
| `bsk fill <ref-or-selector> --value <text>` | Clear and type into input |
| `bsk select <ref-or-selector> --value <v>` | Set `<select>` option(s) by `value` (repeat `--value` for multi-select) |
| `bsk press <key>` | Key/combo (`Enter`, `Ctrl+A`, …; optional `--ref` to focus first) |
### Scripting & timing
| Command | Summary |
|---------|---------|
| `bsk evaluate <expression>` | Run JS in agent tab (see red lines). JS throw → stderr, **exit 0** (RPC success); use `--json` and check `.ok` to detect JS errors |
| `bsk wait-for-navigation` | Block until load/DOM idle/etc. (`--wait-until`, `--timeout`) |
| `bsk wait-ms <duration>` | Sleep (`500ms`, `2s`, `1m`; **no** `--session`) |
### Ask the human for help — `bsk request-help`
When a step needs a human (captcha, login, OTP) or you want the user to
confirm an important action, pause and ask:
bsk request-help --session <id> --prompt "Solve the captcha, then click Done only after the site accepts it" \
--title "Captcha required" --target @e7 --target "#submit" --timeout 5m
- `--prompt` (required): what the user should do.
- `--title` (optional): custom title for the overlay panel. When omitted,
the extension shows its default localized title.
- `--target` (repeatable): a snapshot ref (`@e7`) or CSS selector
(`#submit`) to scroll to and flash-highlight. **Strongly recommended** —
whenever the prompt refers to a concrete element (a button to click, a
field to fill, a checkbox to toggle), pass its `@eN` ref / selector so the
user is guided straight to the right spot instead of hunting for it. For
interaction scenarios, always include the relevant target(s); reserve a
prompt with no `--target` for cases where there is genuinely no specific
element to point at (e.g. "wait for the page to finish loading").
- `--timeout` (default `5m`): how long to wait.
- `--completion-criteria` (optional): JSON success detector. Use it only
when there is a concrete post-help success signal, e.g.
`{"any":[{"url_contains":"/dashboard"},{"selector_exists":"[data-testid='account-menu']"}],"stable_for_ms":1000}`.
The target tab is brought to the foreground; the page stays interactive
while the agent control mask is hidden. The call blocks until the user
explicitly acts, the timeout expires, cancellation arrives, or explicit
completion criteria match. Page reloads, SPA route changes, and captcha
refreshes do not return control by themselves. The result `outcome` is one of:
- `continued` — the user finished and clicked Done / return control (treat as confirm).
- `cancelled` — the user clicked Cancel (treat as reject/abort).
- `timed_out` — nobody acted within the timeout.
- `completed` — the explicit `--completion-criteria` matched while the user had control.
- `navigated` — deprecated legacy outcome. Do not rely on navigation as a completion signal.
`note` carries any text the user typed back. `resolved_targets` reports
which refs/selectors matched a live element.
`request-help` does not refresh the page model after the user returns
control. After a `continued` or `completed` result, issue a separate
observation tool call (usually `bsk snapshot --session <id>`) before using
new refs or reasoning about the post-help page state.
#### Disabling request-help (unattended mode)
Set `BSK_REQUEST_HELP=off` on unattended servers: `bsk request-help` then
returns immediately with `outcome="disabled"` (no overlay, no waiting,
exit 0). Any other value keeps it enabled. If you get `disabled`, do not
retry — complete the task autonomously or stop gracefully.
### Recording — `bsk record`
Capture the user's own actions in the Agent Window to a **trace bundle**, for later LLM-driven automation. New CLI builds request **trace v3** (page observations + action chain); older extensions may still return **trace v2** (actions only), which the CLI exports as a single `trace.json` without `states/`.
```bash
bsk record start --browser <instance-id-or-label> \
[--url https://…] [--purpose "publish a wiki doc"] \
[--max-page-tokens 3000] [--redact-values] \
[--output trace]
# `--url` is optional; default https://example.com/ when omitted (must be http(s)).
# Blocks until the user clicks Finish in the recording panel, then writes:
# trace/trace.json — action chain (+ state index when v3)
# trace/states/ — v3 only: one `sN.txt` observe snapshot per settled page state
bsk record stop [--output trace] # terminal fallback if the browser panel is unavailable
```text
bsk fill <ref> --value <text> bsk select <ref> --value <option-value>
bsk screenshot --out <path> bsk emulate --device <preset-id>
```
- **v3 bundle (preferred):** `--output` is a directory (default `./trace`) containing `trace.json` and `states/`. `trace.json` lists `states[]` (page observation ids) and `steps[]` (each step binds `state` = observe snapshot *before* the action and `result.state` = snapshot *after* settle). Page bodies live in `states/sN.txt` using the same VOM format as `bsk observe`.
- **v2 fallback:** when the connected extension is older, export may contain only legacy `trace.json` with `pages[]` action context and no `states/` observation files. Update the extension for full v3 bundles.
- Each `states[]` entry is one **settled page observation** (captured after recording start, navigation landing, or action settle — not on a timer).
- `target.ref` values like `@e12` exist **only inside** the bundle for disambiguation; do **not** copy `@eN` refs into SKILL.md or agent runbooks — use visible names from the observation text instead.
- `--purpose` is optional context metadata; it does **not** change what gets captured.
- `--redact-values` masks all form values in page files as `[filled]` / `[empty]`.
- Do **not** record on banking/SSO/password-manager pages; passwords are redacted but traces may still contain sensitive text.
`select` matches an option's `value` attribute, not its visible label. Device preset ids are
lowercase and hyphenated, such as `iphone-14`.
## Error handling
- `console` and `network` provide bounded, read-only debugging evidence.
- `emulate` applies viewport, user-agent, and touch overrides to one tab; new tabs do not inherit
them. Use `--off` to restore the real environment.
- `evaluate` is a last resort when observe plus normal interactions cannot complete the task. With
`--json`, inspect `.ok`: a JavaScript exception may still have CLI exit code 0 because the RPC
succeeded. Never evaluate credential surfaces to read storage, cookies, or auth data.
- `record` captures a user's actions for later replay. Read `bsk record start --help` before use,
and never record banking, SSO, password-manager, or other sensitive pages.
### Exit codes (`echo $?` after `bsk …`)
## Recover without wandering
| Code | Meaning | What to do |
|------|---------|------------|
| `0` | Success (including `evaluate` where JS threw but RPC succeeded) | Continue; for `evaluate`, check `--json` `.ok` to distinguish JS success from RPC success |
| `1` | User error — bad args, unknown session, tab not in Agent Window, stale ref | Fix args; `bsk session list`; re-snapshot |
| `2` | Protocol / transport — service unreachable, IPC failure | `bsk doctor`; check extension connected; retry the command |
| `3` | Browser / CDP execution failed | Retry; simplify selector; check tab still open |
| `4` | Timeout | Increase `--timeout`; try `--wait-until domcontentloaded` |
| `5` | Unknown RPC method | This command is not implemented in the current build. Continue the task with other commands. If a newly added command is missing, suggest `bsk update`. |
- Stale ref: observe again and retry the intended action once.
- Unknown tab or session: list current tabs/sessions; never guess identifiers.
- Timeout: inspect current page state before deciding whether one longer purposeful wait is useful.
- Unsupported command: continue with available capabilities; suggest updating only when the missing
command is necessary.
- Unrecoverable failure: report the blocker and stop the session in a finally-style path.
Human errors print `error:` + `hint:` on stderr; `--json` includes `code`, `message`, `hint`, `exit_code`.
### When to run diagnostics
| Situation | Command |
|-----------|---------|
| Before first task in a session | `bsk status` — extension connected? |
| Any failure you cannot fix in one retry | `bsk doctor` |
| Multiple browsers / wrong target | `bsk browsers` then `bsk session start --browser <id>` |
Always **`bsk session stop <id>`** in a `finally`-style path so the Agent Window closes and borrowed tabs return.
## Red lines
1. **No token theft** — do not `bsk evaluate` on sensitive sites to read `localStorage`, cookies, or auth headers for exfiltration.
2. **No long borrow** — do not leave a user's personal tab in the Agent Window across unrelated tasks.
3. **No skip stop** — always `bsk session stop <id>`; never assume idle timeout will clean up.
4. **No post-success control** — once the user’s goal (or last trace step) is met, do not keep operating the page; stop the session unless they asked to keep it open.
5. **No raw observe escalation before snapshot/observe** — use `bsk snapshot` first; use `bsk observe` when VOM semantics help. Only use `bsk get-html` or `bsk screenshot` when snapshot/observe is insufficient. Element screenshots (`--ref @eN`) still require a fresh snapshot/observe ref — never skip observation just to grab a visual.
6. **`evaluate` is powerful and risky** — use only when snapshot + click/fill/select cannot suffice; never on credential surfaces.
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**More detail for any command:** `bsk <cmd> --help`
The CLI's current help and error hints are authoritative for flags, parameters, and recovery
details.