Error reference

Every error code BrowserHive can produce (98 codes), generated from ERROR_REGISTRY in @browserhive/contracts/errors. Each code has a stable anchor: errors.md#<CODE>, which is also the type URL of HTTP problem responses (https://browserhive.ai/docs/errors#<CODE>).

How errors reach you

• MCP tools: the result has isError: true and a text block [CODE] message (a stable text format clients may parse). The structured form { code, message, retryable, hint?, details? } is in _meta["browserhive.ai/error"].
• REST API: application/problem+json (RFC 9457) with type, title, status, detail, plus code, retryable, hint, details and request_id.
• WebSocket: a frame with kind: "error" and payload { code, title, hint?, details?, request_id? }; the corr of the failed command is echoed.
• CLI: boot errors print browserhive: [CODE] message to stderr and exit with the code listed per entry.

Retry guidance

retryable	Meaning
never	do not retry; the request cannot succeed as sent
immediate	safe to retry right away
backoff	retry later with backoff
after_operator	retry after an operator acts (unlock the vault, resolve a request, change policy)
different_args	retry only with different arguments

Domain errors

Returned by tools and the REST API when a request cannot be served (unknown session, blocked URL, vault locked…).

Code	Title	HTTP	Retryable
SESSION_NOT_FOUND	Session not found	404	different_args
SESSION_ALREADY_EXISTS	Session id collision	409	immediate
SESSION_DEAD	Session is dead	410	different_args
SESSION_LIMIT_REACHED	Session limit reached	429	backoff
SESSION_ACCESS_DENIED	Session not found	404	never
SESSION_NOT_AVAILABLE	Session not available	409	after_operator
SESSION_NOT_LIVE	Session is not live	409	never
SESSION_LIVE	Session is still live	409	never
UNKNOWN_CHANNEL	Unknown browser channel	400	different_args
INVALID_SLUG	Invalid slug	400	different_args
UNSAFE_LAUNCH_ARG	Launch argument denied	400	different_args
INVALID_PERSISTENCE_CONFIG	Invalid persistence config	400	different_args
TAB_NOT_FOUND	Tab not found	404	different_args
PATH_NOT_ALLOWED	Path outside the sandbox	400	different_args
AUTH_STATE_NOT_FOUND	Saved auth state not found	404	different_args
EVALUATE_DISABLED	evaluate is disabled	403	never
ELEMENT_NOT_ACTIONABLE	Element not actionable	422	backoff
ELEMENT_NOT_FOUND	Element not found	404	different_args
NAVIGATION_TIMEOUT	Navigation timed out	504	backoff
NAVIGATION_FAILED	Navigation failed	502	backoff
WAIT_TIMEOUT	Wait timed out	504	backoff
SCRIPT_ERROR	Script threw	422	different_args
DOWNLOAD_FAILED	Download failed	502	backoff
UPLOAD_FAILED	Upload failed	422	different_args
PAGE_CLOSED	Page closed	410	different_args
BROWSER_CRASHED	Browser crashed	500	after_operator
URL_BLOCKED	URL blocked by policy	403	never
BROWSER_NOT_INSTALLED	Browser not installed	503	after_operator
VAULT_NOT_CONFIGURED	No vault configured	404	never
VAULT_LOCKED	Vault locked	409	after_operator
VAULT_ENTRY_NOT_FOUND	Vault entry not found	404	different_args
VAULT_NOT_AUTHORIZED	Vault entry not authorized	403	never
EVALUATE_REQUIRED_OFF	Entry requires evaluate disabled	403	never
DASHBOARD_DENIED	Fill denied by operator	403	after_operator
VAULT_UNLOCK_FAILED	Vault unlock failed	401	different_args
VAULT_SYNC_UNSUPPORTED	Vault sync unsupported	400	never
VAULT_BACKEND_ERROR	Vault backend error	502	backoff
ATTENTION_REQUIRES_HTTP	Attention requires http	400	never
ATTENTION_NOT_OPEN	Attention request is not open	409	never
CONFIRM_NOT_OPEN	Confirmation is not open	409	never
INPUT_NOT_PERMITTED	Input not permitted	409	after_operator
SCREENCAST_FAILED	Screencast failed	502	backoff
TOOL_NOT_AVAILABLE	Tool not available	400	never
INVALID_ARGUMENTS	Invalid arguments	400	different_args
TRACE_UNAVAILABLE	Trace unavailable	404	never
SCREENSHOT_UNAVAILABLE	Screenshot unavailable	404	never
INTERNAL_ERROR	Internal error	500	backoff

SESSION_NOT_FOUND

Property	Value
Title	Session not found
HTTP status	404
Category	domain
Retryable	different_args (retry only with different arguments)

Message: No browser session with id '{session_id}'

Hint: Use list_sessions to see live sessions.

Cause: The session id is unknown, mistyped, or the session was already closed and removed.

Resolution: Call list_sessions and use one of the returned ids, or launch a new session.

Details:

Field	Type	Required	Constraints
session_id	string	yes	—

SESSION_ALREADY_EXISTS

Property	Value
Title	Session id collision
HTTP status	409
Category	domain
Retryable	immediate (safe to retry right away)

Message: Session '{session_id}' already exists. Slug+nanoid collision is exceptionally rare; the caller should retry.

Hint: Retry launch_session; a fresh id is generated on every call.

Cause: The generated <slug>-<nanoid8> id collided with a live session (36^8 space).

Resolution: Retry immediately; a collision twice in a row indicates a broken id generator.

Details:

Field	Type	Required	Constraints
session_id	string	yes	—

SESSION_DEAD

Property	Value
Title	Session is dead
HTTP status	410
Category	domain
Retryable	different_args (retry only with different arguments)

Message: Session '{session_id}' is dead — its underlying browser process crashed.

Hint: Close the session and launch a new one.

Cause: The browser context or process disconnected; the session is awaiting reaping.

Resolution: Launch a replacement session; the crashed one is closed with reason crash.

Details:

Field	Type	Required	Constraints
session_id	string	yes	—

SESSION_LIMIT_REACHED

Property	Value
Title	Session limit reached
HTTP status	429
Category	domain
Retryable	backoff (retry later with backoff)

Message: Concurrent session limit reached (max={limit}). Close a session and retry.

Hint: Close an idle session or wait for a lease to expire, then retry.

Cause: The number of live sessions equals maxSessions (derived from host RAM by default).

Resolution: Close sessions you no longer need, or raise maxSessions on a host with more memory.

Details:

Field	Type	Required	Constraints
limit	integer	yes	—
live	integer	yes	—

SESSION_ACCESS_DENIED

Property	Value
Title	Session not found
HTTP status	404
Category	domain
Retryable	never (do not retry; the request cannot succeed as sent)

Message: No browser session with id '{session_id}'

Hint: Use list_sessions to see the sessions you own.

Cause: The session belongs to a different principal and ownership enforcement is on (auth=token).

Resolution: Only the owning principal may use a session; launch your own.

Details:

Field	Type	Required	Constraints
session_id	string	yes	—

SESSION_NOT_AVAILABLE

Property	Value
Title	Session not available
HTTP status	409
Category	domain
Retryable	after_operator (retry after an operator acts (unlock the vault, resolve a request, change policy))

Message: Session '{session_id}' is not available (state: {state}).

Hint: Wait until the session is live, or pick another session.

Cause: The session is launching, draining, paused for an operator, closed or crashed.

Resolution: Retry once the session state returns to live.

Details:

Field	Type	Required	Constraints
session_id	string	yes	—
state	string	yes	—

SESSION_NOT_LIVE

Property	Value
Title	Session is not live
HTTP status	409
Category	domain
Retryable	never (do not retry; the request cannot succeed as sent)

Message: Session '{session_id}' is not live.

Hint: This action needs a live session; the session has ended.

Cause: An operator action that needs a running browser (live view, input, terminate) targeted a closed session.

Resolution: Open the trace or history views instead.

Details:

Field	Type	Required	Constraints
session_id	string	yes	—

SESSION_LIVE

Property	Value
Title	Session is still live
HTTP status	409
Category	domain
Retryable	never (do not retry; the request cannot succeed as sent)

Message: Session '{session_id}' is still live.

Hint: Terminate or close the session first.

Cause: An action that needs a finished session (archive, delete, trace download) targeted a live one.

Resolution: Close the session, then retry.

Details:

Field	Type	Required	Constraints
session_id	string	yes	—

UNKNOWN_CHANNEL

Property	Value
Title	Unknown browser channel
HTTP status	400
Category	domain
Retryable	different_args (retry only with different arguments)

Message: Unknown browser channel '{channel}'. Expected one of: chromium, chrome, edge.

Hint: Pass channel as one of chromium, chrome or edge.

Cause: The channel argument is not a supported Chromium-family channel.

Resolution: Use chromium (bundled), or chrome/edge when that browser is installed on the host.

Details:

Field	Type	Required	Constraints
channel	string	yes	—
supported	string[]	yes	—

INVALID_SLUG

Property	Value
Title	Invalid slug
HTTP status	400
Category	domain
Retryable	different_args (retry only with different arguments)

Message: Invalid slug '{slug}'. Slugs must match /^[a-z][a-z0-9-]{1,31}$/ (start with a lowercase letter, 2–32 chars, lowercase alphanumerics and dashes).

Hint: Use a short lowercase name such as “shop” or “docs-crawl”.

Cause: The slug does not match the filesystem-safe grammar.

Resolution: Lowercase letters, digits and dashes only; start with a letter; 2–32 characters.

Details:

Field	Type	Required	Constraints
slug	string	yes	—
pattern	string	yes	—

UNSAFE_LAUNCH_ARG

Property	Value
Title	Launch argument denied
HTTP status	400
Category	domain
Retryable	different_args (retry only with different arguments)

Message: Launch arg '{arg}' is on the deny-list and would break session isolation.

Hint: Remove the argument from launch_options.args.

Cause: A Chromium flag that changes the profile directory, sandbox or debugging surface was passed.

Resolution: Use the persistence modes and channel options instead of raw isolation-breaking flags.

Details:

Field	Type	Required	Constraints
arg	string	yes	—

INVALID_PERSISTENCE_CONFIG

Property	Value
Title	Invalid persistence config
HTTP status	400
Category	domain
Retryable	different_args (retry only with different arguments)

Message: Invalid persistence config: {reason}

Hint: Check the persistence_mode / restore_profile / storage_state / incognito combination.

Cause: The requested combination of persistence mode and launch options is contradictory.

Resolution: See the persistence matrix in the tool reference and pick a consistent combination.

Details:

Field	Type	Required	Constraints
reason	string	yes	—

TAB_NOT_FOUND

Property	Value
Title	Tab not found
HTTP status	404
Category	domain
Retryable	different_args (retry only with different arguments)

Message: Tab '{tab_id}' not found in session '{session_id}'.

Hint: Use list_tabs to see open tabs.

Cause: The tab id is unknown or the tab was closed; <active> means the session has no open tab.

Resolution: Call list_tabs, or open a tab with new_tab.

Details:

Field	Type	Required	Constraints
session_id	string	yes	—
tab_id	string	yes	—

PATH_NOT_ALLOWED

Property	Value
Title	Path outside the sandbox
HTTP status	400
Category	domain
Retryable	different_args (retry only with different arguments)

Message: Path '{path}' is outside the allowed sandbox roots.

Hint: Use a relative path or an absolute path under an allowed root.

Cause: The resolved path (symlinks followed) escapes the session directory and the uploads directory.

Resolution: Write inside the session directory (relative paths resolve there) or the uploads directory.

Details:

Field	Type	Required	Constraints
path	string	yes	—
roots	string[]	yes	—

AUTH_STATE_NOT_FOUND

Property	Value
Title	Saved auth state not found
HTTP status	404
Category	domain
Retryable	different_args (retry only with different arguments)

Message: No saved {kind_label} snapshot named '{name}'. Use list_saved_auths to see what is available.

Hint: Call list_saved_auths and use one of the returned names.

Cause: No snapshot of the requested kind exists under that name in the auth-states directory.

Resolution: Save one with save_storage_state or save_full_profile first.

Details:

Field	Type	Required	Constraints
name	string	yes	—
kind	one of storage, profile	yes	—

EVALUATE_DISABLED

Property	Value
Title	evaluate is disabled
HTTP status	403
Category	domain
Retryable	never (do not retry; the request cannot succeed as sent)

Message: The 'evaluate' tool is disabled for session '{session_id}'.

Hint: Use the structured tools (click, fill, get_content, snapshot) instead.

Cause: The session was launched with disable_evaluate: true, or the server runs with allowEvaluate=false.

Resolution: Relaunch without disable_evaluate, or ask the operator to enable allowEvaluate.

Details:

Field	Type	Required	Constraints
session_id	string	yes	—
scope	one of session, server	yes	—

ELEMENT_NOT_ACTIONABLE

Property	Value
Title	Element not actionable
HTTP status	422
Category	domain
Retryable	backoff (retry later with backoff)

Message: Element '{selector}' did not become actionable within the timeout — it may be hidden, detached, disabled, covered by another element, or the selector matched the wrong element. Use a more specific, visible selector, or raise the timeout.

Hint: Take a snapshot to find a visible, unique selector; raise timeout_ms if the page is slow.

Cause: The target was hidden, detached, disabled, covered, or the selector matched the wrong element.

Resolution: Use a more specific selector or wait for the element to become visible first.

Details:

Field	Type	Required	Constraints
selector	string	yes	—
detail	string	no	—

ELEMENT_NOT_FOUND

Property	Value
Title	Element not found
HTTP status	404
Category	domain
Retryable	different_args (retry only with different arguments)

Message: No element matched selector '{selector}'.

Hint: Take a snapshot and pick a selector that matches exactly one element.

Cause: The selector matched nothing, or matched several elements under strict mode.

Resolution: Refine the selector; count in details tells you how many matched.

Details:

Field	Type	Required	Constraints
selector	string	yes	—
count	integer	no	—

NAVIGATION_TIMEOUT

Property	Value
Title	Navigation timed out
HTTP status	504
Category	domain
Retryable	backoff (retry later with backoff)

Message: Navigation to '{url}' did not finish within {timeout_ms} ms.

Hint: Retry with a longer timeout_ms or a lighter wait_until (commit, domcontentloaded).

Cause: The page did not reach the requested load state before the timeout.

Resolution: Raise the timeout, choose an earlier wait_until, or check the network.

Details:

Field	Type	Required	Constraints
url	string	yes	—
timeout_ms	integer	yes	—

NAVIGATION_FAILED

Property	Value
Title	Navigation failed
HTTP status	502
Category	domain
Retryable	backoff (retry later with backoff)

Message: Navigation to '{url}' failed ({net_error}).

Hint: Check the URL and network; net_error names the Chromium failure.

Cause: Chromium reported a network error (net::ERR_*): DNS, TLS, connection refused, and so on.

Resolution: Verify the URL resolves and is reachable from the host; retry transient failures.

Details:

Field	Type	Required	Constraints
url	string	yes	—
net_error	string	yes	—

WAIT_TIMEOUT

Property	Value
Title	Wait timed out
HTTP status	504
Category	domain
Retryable	backoff (retry later with backoff)

Message: Timed out after {timeout_ms} ms waiting for {what}.

Hint: Raise timeout_ms or wait for a different condition.

Cause: The awaited selector state, URL or load state did not occur in time.

Resolution: Check the page state with snapshot, then wait for a condition that will happen.

Details:

Field	Type	Required	Constraints
what	string	yes	—
timeout_ms	integer	yes	—

SCRIPT_ERROR

Property	Value
Title	Script threw
HTTP status	422
Category	domain
Retryable	different_args (retry only with different arguments)

Message: The evaluated script threw: {message}

Hint: Fix the script; the first line of the page error is in details.message.

Cause: The expression passed to evaluate threw inside the page.

Resolution: Correct the script or guard against missing globals.

Details:

Field	Type	Required	Constraints
message	string	yes	—

DOWNLOAD_FAILED

Property	Value
Title	Download failed
HTTP status	502
Category	domain
Retryable	backoff (retry later with backoff)

Message: Download failed: {reason}

Hint: Retry; if it persists, check that the link starts a download.

Cause: The browser reported the download as failed or cancelled.

Resolution: Retry the download; verify the target actually serves a file.

Details:

Field	Type	Required	Constraints
reason	string	yes	—

UPLOAD_FAILED

Property	Value
Title	Upload failed
HTTP status	422
Category	domain
Retryable	different_args (retry only with different arguments)

Message: Upload failed: {reason}

Hint: Check that the selector targets a file input and the file exists under uploads/.

Cause: setInputFiles failed: wrong element, missing file, or a page that rejected the input.

Resolution: Target an <input type=file> and place the file in the uploads directory.

Details:

Field	Type	Required	Constraints
reason	string	yes	—

PAGE_CLOSED

Property	Value
Title	Page closed
HTTP status	410
Category	domain
Retryable	different_args (retry only with different arguments)

Message: Tab '{tab_id}' was closed while the action was running.

Hint: Use list_tabs and target an open tab.

Cause: The page or its execution context was destroyed mid-call (closed tab, navigation away).

Resolution: Re-open or re-target the tab and retry.

Details:

Field	Type	Required	Constraints
tab_id	string	yes	—

BROWSER_CRASHED

Property	Value
Title	Browser crashed
HTTP status	500
Category	domain
Retryable	after_operator (retry after an operator acts (unlock the vault, resolve a request, change policy))

Message: The browser behind session '{session_id}' crashed.

Hint: Launch a new session; the crashed one will be reaped.

Cause: The browser context or process was closed unexpectedly.

Resolution: Launch a replacement session; check host memory if it repeats.

Details:

Field	Type	Required	Constraints
session_id	string	yes	—

URL_BLOCKED

Property	Value
Title	URL blocked by policy
HTTP status	403
Category	domain
Retryable	never (do not retry; the request cannot succeed as sent)

Message: The URL '{url}' is blocked by the administrator (matched the blocklist pattern '{pattern}'). This is an operator policy, not a transient failure — do not retry this URL, and do not try to reach it by another route. Report it to the user if the task cannot continue.

Hint: Do not retry; report the block to the user.

Cause: The URL matched a pattern in the operator blocklist (blocklist file).

Resolution: Operators edit the blocklist file (reloaded live) if the block is unintended.

Details:

Field	Type	Required	Constraints
url	string	yes	—
pattern	string	yes	—

BROWSER_NOT_INSTALLED

Property	Value
Title	Browser not installed
HTTP status	503
Category	domain
Retryable	after_operator (retry after an operator acts (unlock the vault, resolve a request, change policy))

Message: No browser is installed for channel '{channel}'. Run '{install_command}' on the host.

Hint: Ask the operator to run browserhive init.

Cause: The Chromium binary for the driver/channel is missing (no postinstall download, D-18).

Resolution: Run browserhive init, or install the branded browser for chrome/edge.

Details:

Field	Type	Required	Constraints
channel	string	yes	—
install_command	string	yes	—

VAULT_NOT_CONFIGURED

Property	Value
Title	No vault configured
HTTP status	404
Category	domain
Retryable	never (do not retry; the request cannot succeed as sent)

Message: No vault backend is configured. Start the server with --vault <backend>.

Hint: Ask the operator to start the server with vault=bitwarden.

Cause: The server runs with vault=off.

Resolution: Start with --vault bitwarden and unlock it.

Details: none.

VAULT_LOCKED

Property	Value
Title	Vault locked
HTTP status	409
Category	domain
Retryable	after_operator (retry after an operator acts (unlock the vault, resolve a request, change policy))

Message: Vault backend is locked. Unlock it on the dashboard Vault page.

Hint: Ask the operator to unlock the vault, then retry.

Cause: The backend session token is absent or expired.

Resolution: Run bw unlock --raw and paste the session token on the dashboard Vault page, or restart the server with BW_SESSION exported.

Details:

Field	Type	Required	Constraints
backend	string	yes	—

VAULT_ENTRY_NOT_FOUND

Property	Value
Title	Vault entry not found
HTTP status	404
Category	domain
Retryable	different_args (retry only with different arguments)

Message: Vault entry '{entry_name}' is not in the backend.

Hint: Use vault_list_available to see entries you may fill.

Cause: No binding or backend item matches the requested entry name.

Resolution: Pick a name from vault_list_available, or ask the operator to bind the item.

Details:

Field	Type	Required	Constraints
entry_name	string	yes	—

VAULT_NOT_AUTHORIZED

Property	Value
Title	Vault entry not authorized
HTTP status	403
Category	domain
Retryable	never (do not retry; the request cannot succeed as sent)

Message: Vault entry '{entry_name}' is not authorized for this session's slug.

Hint: The operator controls which sessions may use this entry.

Cause: The binding or group policy does not allow this principal and session slug.

Resolution: Operators edit the binding (slug globs, principals) on the Vault page.

Details:

Field	Type	Required	Constraints
entry_name	string	yes	—

EVALUATE_REQUIRED_OFF

Property	Value
Title	Entry requires evaluate disabled
HTTP status	403
Category	domain
Retryable	never (do not retry; the request cannot succeed as sent)

Message: Vault entry '{entry_name}' requires the session to have evaluate disabled (launch with disable_evaluate: true).

Hint: Relaunch the session with disable_evaluate: true.

Cause: The binding is marked require_no_evaluate and the session can run scripts.

Resolution: Launch with disable_evaluate: true before filling this entry.

Details:

Field	Type	Required	Constraints
entry_name	string	yes	—

DASHBOARD_DENIED

Property	Value
Title	Fill denied by operator
HTTP status	403
Category	domain
Retryable	after_operator (retry after an operator acts (unlock the vault, resolve a request, change policy))

Message: Vault fill for '{entry_name}' was denied by the dashboard (or timed out waiting for confirmation).

Hint: Ask the operator to approve the fill, then retry.

Cause: The operator rejected the confirmation, or nobody answered before the deadline.

Resolution: Retry when an operator is available to confirm.

Details:

Field	Type	Required	Constraints
request_id	string	yes	—
entry_name	string	no	—

VAULT_UNLOCK_FAILED

Property	Value
Title	Vault unlock failed
HTTP status	401
Category	domain
Retryable	different_args (retry only with different arguments)

Message: Vault unlock failed ({mode}).

Hint: Create a new session token with bw unlock --raw and paste it again.

Cause: The backend rejected the session token (expired after bw lock or bw logout, or from another bw login), or the passphrase of a passphrase backend.

Resolution: Run bw unlock --raw as the user that runs BrowserHive and paste the new token, or export it as BW_SESSION before start.

Details:

Field	Type	Required	Constraints
mode	string	yes	—

VAULT_SYNC_UNSUPPORTED

Property	Value
Title	Vault sync unsupported
HTTP status	400
Category	domain
Retryable	never (do not retry; the request cannot succeed as sent)

Message: Vault backend '{backend}' does not support sync.

Hint: Nothing to do; this backend has no sync operation.

Cause: The backend capabilities report sync: false.

Resolution: Use a backend that supports sync, or skip the call.

Details:

Field	Type	Required	Constraints
backend	string	yes	—

VAULT_BACKEND_ERROR

Property	Value
Title	Vault backend error
HTTP status	502
Category	domain
Retryable	backoff (retry later with backoff)

Message: Vault backend '{backend}' failed ({kind}).

Hint: Retry; if it persists, check the backend CLI on the host.

Cause: The backend CLI is missing, timed out, or exited with an error.

Resolution: Install or repair the backend CLI (bw) and retry.

Details:

Field	Type	Required	Constraints
backend	string	yes	—
kind	one of not_installed, timeout, exit	yes	—

ATTENTION_REQUIRES_HTTP

Property	Value
Title	Attention requires http
HTTP status	400
Category	domain
Retryable	never (do not retry; the request cannot succeed as sent)

Message: '{tool}' requires the http transport; human-in-the-loop attention is not available under stdio.

Hint: Run the server with transport=http and admin=true.

Cause: Attention needs the shared, long-lived HTTP daemon and the dashboard; stdio is single-client.

Resolution: Start BrowserHive with --admin (http transport).

Details:

Field	Type	Required	Constraints
tool	string	yes	—

ATTENTION_NOT_OPEN

Property	Value
Title	Attention request is not open
HTTP status	409
Category	domain
Retryable	never (do not retry; the request cannot succeed as sent)

Message: Attention request '{request_id}' is not open (status: {status}).

Hint: Refresh the queue.

Cause: The request was already resolved, rejected, timed out or cancelled.

Resolution: Nothing to do; the outcome is final.

Details:

Field	Type	Required	Constraints
request_id	string	yes	—
status	string	yes	—

CONFIRM_NOT_OPEN

Property	Value
Title	Confirmation is not open
HTTP status	409
Category	domain
Retryable	never (do not retry; the request cannot succeed as sent)

Message: Vault confirmation '{request_id}' is not open (status: {status}).

Hint: Refresh the confirm queue.

Cause: The confirmation was already decided or expired.

Resolution: Nothing to do; the outcome is final.

Details:

Field	Type	Required	Constraints
request_id	string	yes	—
status	string	yes	—

INPUT_NOT_PERMITTED

Property	Value
Title	Input not permitted
HTTP status	409
Category	domain
Retryable	after_operator (retry after an operator acts (unlock the vault, resolve a request, change policy))

Message: Input is not permitted on session '{session_id}': no takeover attention request is open.

Hint: Input is only accepted while a takeover attention request is open.

Cause: Live-view input is gated on an open takeover request from the agent.

Resolution: Wait for the agent to request attention in takeover mode.

Details:

Field	Type	Required	Constraints
session_id	string	yes	—

SCREENCAST_FAILED

Property	Value
Title	Screencast failed
HTTP status	502
Category	domain
Retryable	backoff (retry later with backoff)

Message: Screencast for session '{session_id}' failed: {reason}

Hint: Retry; if the session is closing the stream cannot start.

Cause: The CDP screencast could not be started or the bridge lost its page.

Resolution: Retry the live view; check the session is live.

Details:

Field	Type	Required	Constraints
session_id	string	yes	—
reason	string	yes	—

TOOL_NOT_AVAILABLE

Property	Value
Title	Tool not available
HTTP status	400
Category	domain
Retryable	never (do not retry; the request cannot succeed as sent)

Message: Tool '{tool}' is not available on this server (requires {requires}).

Hint: The tool needs a server feature that is off.

Cause: The tool pack requires a transport, vault or admin feature that is not enabled.

Resolution: Enable the feature on the server, or avoid the tool.

Details:

Field	Type	Required	Constraints
tool	string	yes	—
requires	string	yes	—

INVALID_ARGUMENTS

Property	Value
Title	Invalid arguments
HTTP status	400
Category	domain
Retryable	different_args (retry only with different arguments)

Message: Invalid arguments: {summary}

Hint: Fix the listed issues and call the tool again.

Cause: The tool arguments failed schema validation.

Resolution: Each issue names the path and what is wrong.

Details:

Field	Type	Required	Constraints
issues	object[]	yes	each item: keys path, message

TRACE_UNAVAILABLE

Property	Value
Title	Trace unavailable
HTTP status	404
Category	domain
Retryable	never (do not retry; the request cannot succeed as sent)

Message: No trace is available for this session.

Hint: Tracing is on when trace=true (default with admin).

Cause: Tracing was off for the session, or the trace failed to finalize.

Resolution: Enable trace and relaunch; see TRACE_START_FAILED warnings.

Details:

Field	Type	Required	Constraints
enabled	boolean	yes	—

SCREENSHOT_UNAVAILABLE

Property	Value
Title	Screenshot unavailable
HTTP status	404
Category	domain
Retryable	never (do not retry; the request cannot succeed as sent)

Message: No screenshot is stored for event '{event_id}'.

Hint: Screenshots are kept per tool call while retention allows.

Cause: The event produced no screenshot, or retention removed it.

Resolution: Nothing to do; the artifact no longer exists.

Details:

Field	Type	Required	Constraints
event_id	string	yes	—

INTERNAL_ERROR

Property	Value
Title	Internal error
HTTP status	500
Category	domain
Retryable	backoff (retry later with backoff)

Message: Internal error (ref {ref}).

Hint: Quote the ref to the operator; the logs hold the detail.

Cause: An unexpected failure that no typed code describes.

Resolution: Search the logs for the ref (request id) and file a bug if it repeats.

Details:

Field	Type	Required	Constraints
ref	string	yes	—

Boot errors

Stop the process before it serves anything. The CLI prints [CODE] message and exits with the listed exit code.

Code	Title	HTTP	Retryable
ADMIN_REQUIRES_HTTP	Dashboard requires http	500	never
INSECURE_BIND_REFUSED	Insecure bind refused	500	never
PORT_IN_USE	Port in use	500	never
BIND_FAILED	Bind failed	500	never
CONFIG_INVALID	Invalid configuration value	400	never
CONFIG_UNKNOWN_KEY	Unknown configuration key	400	never
BLOCKLIST_LOAD_FAILED	Blocklist could not be loaded	400	never
DATA_DIR_UNWRITABLE	Data directory not writable	500	never
DATA_DIR_LOCKED	Data directory in use	409	never
DB_OPEN_FAILED	Database could not be opened	500	never
DB_NEWER_THAN_BINARY	Database newer than this version	500	never
MIGRATION_FAILED	Migration failed	500	never
DB_CORRUPT	Database corrupt	500	never
UNHANDLED	Unhandled error	500	never
RETENTION_FAILED	Retention sweep failed	500	backoff
STALE_BROWSER_PROCESSES	Stale browser processes found	500	never

ADMIN_REQUIRES_HTTP

Property	Value
Title	Dashboard requires http
HTTP status	500
Category	boot
Retryable	never (do not retry; the request cannot succeed as sent)
Exit code	3

Message: admin=true requires transport=http. The dashboard is not available under stdio.

Hint: Drop admin=true, or use transport=http.

Cause: admin=true was combined with transport=stdio; stdio is single-client and cannot host the dashboard.

Resolution: Run with the http transport (the default) to use the dashboard.

Details: none.

INSECURE_BIND_REFUSED

Property	Value
Title	Insecure bind refused
HTTP status	500
Category	boot
Retryable	never (do not retry; the request cannot succeed as sent)
Exit code	3

Message: Refusing to bind {host} without authentication. Set auth=token, or set allowInsecureBind=true to accept the risk.

Hint: Set auth=token for LAN exposure.

Cause: A non-loopback host was requested without auth=token and without allowInsecureBind=true.

Resolution: Enable token auth, or acknowledge the risk with allowInsecureBind=true.

Details:

Field	Type	Required	Constraints
host	string	yes	—

PORT_IN_USE

Property	Value
Title	Port in use
HTTP status	500
Category	boot
Retryable	never (do not retry; the request cannot succeed as sent)
Exit code	3

Message: Cannot listen on {host}:{port}: the port is already in use ({errno}).

Hint: Pick another port with –port, or stop the process holding it.

Cause: Another process (often a previous BrowserHive) is bound to the same host and port.

Resolution: Stop the other process or choose a free port.

Details:

Field	Type	Required	Constraints
host	string	yes	—
port	integer	yes	—
errno	string	yes	—

BIND_FAILED

Property	Value
Title	Bind failed
HTTP status	500
Category	boot
Retryable	never (do not retry; the request cannot succeed as sent)
Exit code	1

Message: Cannot listen on {host}:{port} ({errno}).

Hint: Check the address exists on this host and the port is permitted.

Cause: The listener could not bind for a reason other than a busy port (EACCES, EADDRNOTAVAIL…).

Resolution: Use an address assigned to this host and an unprivileged port.

Details:

Field	Type	Required	Constraints
host	string	yes	—
port	integer	yes	—
errno	string	yes	—

CONFIG_INVALID

Property	Value
Title	Invalid configuration value
HTTP status	400
Category	boot
Retryable	never (do not retry; the request cannot succeed as sent)
Exit code	64

Message: invalid value for {source}: {reason}

Hint: Run ‘browserhive config validate’ to see every problem.

Cause: A value failed its grammar, range or a cross-field rule.

Resolution: Fix the value at the named source; the grammar is in the message.

Details:

Field	Type	Required	Constraints
key	string	yes	—
source	string	yes	—
reason	string	yes	—

CONFIG_UNKNOWN_KEY

Property	Value
Title	Unknown configuration key
HTTP status	400
Category	boot
Retryable	never (do not retry; the request cannot succeed as sent)
Exit code	64

Message: unknown key '{key}' in {source}.

Hint: Run ‘browserhive –help’ for the list of keys.

Cause: A flag, environment variable or config-file key is not in the registry (typo or removed knob).

Resolution: Use the suggested name; kebab-case flag spellings are not supported.

Details:

Field	Type	Required	Constraints
key	string	yes	—
source	string	yes	—
suggestion	string	no	—

BLOCKLIST_LOAD_FAILED

Property	Value
Title	Blocklist could not be loaded
HTTP status	400
Category	boot
Retryable	never (do not retry; the request cannot succeed as sent)
Exit code	3

Message: Cannot load blocklist {path}: {reason}

Hint: Check the path and file permissions.

Cause: The configured blocklist file is missing, unreadable or over the entry cap.

Resolution: Fix the file; a configured-but-unreadable blocklist is fatal by design.

Details:

Field	Type	Required	Constraints
path	string	yes	—
reason	string	yes	—

DATA_DIR_UNWRITABLE

Property	Value
Title	Data directory not writable
HTTP status	500
Category	boot
Retryable	never (do not retry; the request cannot succeed as sent)
Exit code	1

Message: The data directory {path} is not writable.

Hint: Fix permissions or choose another dataDir.

Cause: The data directory could not be created with mode 0700 or is owned by another user.

Resolution: Point dataDir at a directory the server user owns.

Details:

Field	Type	Required	Constraints
path	string	yes	—

DATA_DIR_LOCKED

Property	Value
Title	Data directory in use
HTTP status	409
Category	boot
Retryable	never (do not retry; the request cannot succeed as sent)
Exit code	3

Message: The data directory {path} is in use by another BrowserHive process (pid {pid}).

Hint: Stop the running server first, or point dataDir at another directory.

Cause: A live process holds <data-dir>/browserhive.lock; one server (or one maintenance command) owns a data directory at a time.

Resolution: Stop that process. A lock left by a crashed process is detected (its pid is gone) and replaced automatically.

Details:

Field	Type	Required	Constraints
path	string	yes	—
pid	integer	yes	—

DB_OPEN_FAILED

Property	Value
Title	Database could not be opened
HTTP status	500
Category	boot
Retryable	never (do not retry; the request cannot succeed as sent)
Exit code	1

Message: Cannot open database {path}: {reason}

Hint: Run ‘browserhive db status’ for details.

Cause: SQLite refused to open the file (locked, permissions, wrong application_id).

Resolution: Check for another running server and file permissions.

Details:

Field	Type	Required	Constraints
path	string	yes	—
reason	string	yes	—

DB_NEWER_THAN_BINARY

Property	Value
Title	Database newer than this version
HTTP status	500
Category	boot
Retryable	never (do not retry; the request cannot succeed as sent)
Exit code	3

Message: The database schema (v{db_version}, readable from v{min_reader_version}) is newer than this binary supports (v{binary_version}).

Hint: Upgrade BrowserHive, or restore the pre-upgrade backup with ‘browserhive db restore ’.

Cause: A newer BrowserHive migrated the database past this binary’s compatibility window (D-04).

Resolution: Upgrade, or restore the named backup to downgrade.

Details:

Field	Type	Required	Constraints
db_version	integer	yes	—
min_reader_version	integer	yes	—
binary_version	integer	yes	—
backup_path	string	no	—

MIGRATION_FAILED

Property	Value
Title	Migration failed
HTTP status	500
Category	boot
Retryable	never (do not retry; the request cannot succeed as sent)
Exit code	1

Message: Migration '{name}' (v{from} → v{to}) failed. The pre-migration backup is at {backup_path}.

Hint: The database was rolled back; report the failure with the log.

Cause: A migration step raised inside the transaction; the transaction was rolled back.

Resolution: File a bug with the log; restore the backup if the database is unusable.

Details:

Field	Type	Required	Constraints
from	integer	yes	—
to	integer	yes	—
name	string	yes	—
backup_path	string	yes	—

DB_CORRUPT

Property	Value
Title	Database corrupt
HTTP status	500
Category	boot
Retryable	never (do not retry; the request cannot succeed as sent)
Exit code	1

Message: The database {path} is corrupt; it was moved to {quarantine_path}.

Hint: Restore a backup with ‘browserhive db restore ’ or start fresh.

Cause: PRAGMA quick_check failed or SQLite reported corruption.

Resolution: Restore the most recent backup from backups/.

Details:

Field	Type	Required	Constraints
path	string	yes	—
quarantine_path	string	yes	—

UNHANDLED

Property	Value
Title	Unhandled error
HTTP status	500
Category	boot
Retryable	never (do not retry; the request cannot succeed as sent)
Exit code	1

Message: Unhandled {kind} reached the process handler: {name}.

Hint: Check the log for the stack; the server keeps running when the failure is contained.

Cause: A promise rejected with no handler or an exception escaped every boundary; the CLI process handlers record it as a degradation (spec 10 §3).

Resolution: Report the log line; repeated occurrences on /system.degradations indicate a bug in a background task.

Details:

Field	Type	Required	Constraints
kind	one of exception, rejection	yes	—
name	string	yes	—

RETENTION_FAILED

Property	Value
Title	Retention sweep failed
HTTP status	500
Category	boot
Retryable	backoff (retry later with backoff)
Exit code	1

Message: Retention step {step} failed: {reason}

Hint: The sweep retries on the next interval; check disk space and file permissions.

Cause: A step of the periodic retention sweep (row pruning, byte cap, vacuum or artifact enqueue) threw. Recorded as a degradation, never fatal.

Resolution: Fix the underlying cause (disk, permissions, locks); the degradation resolves on the next clean pass.

Details:

Field	Type	Required	Constraints
step	string	yes	—
reason	string	yes	—

STALE_BROWSER_PROCESSES

Property	Value
Title	Stale browser processes found
HTTP status	500
Category	boot
Retryable	never (do not retry; the request cannot succeed as sent)
Exit code	1

Message: {count} browser process(es) from a previous run are still alive.

Hint: Stop them manually if they hold profile locks or memory.

Cause: Chromium processes launched by an earlier BrowserHive survived its exit (crash or SIGKILL). Recorded as a boot-time degradation, never fatal.

Resolution: Kill the listed processes; they are not adopted by the new server.

Details:

Field	Type	Required	Constraints
count	integer	yes	—

Authentication errors

Returned by the REST API, /mcp and the WebSocket handshake.

Code	Title	HTTP	Retryable
UNAUTHORIZED	Unauthorized	401	never
INVALID_CREDENTIALS	Invalid credentials	401	never
FORBIDDEN	Forbidden	403	never
PASSWORD_CHANGE_REQUIRED	Password change required	403	after_operator
BAD_CURRENT_PASSWORD	Current password incorrect	400	different_args
WEAK_PASSWORD	Password too weak	400	different_args

UNAUTHORIZED

Property	Value
Title	Unauthorized
HTTP status	401
Category	auth
Retryable	never (do not retry; the request cannot succeed as sent)

Message: Authentication required.

Hint: Log in, or send a valid bearer token.

Cause: No credential was presented, or the presented one is invalid or expired.

Resolution: Authenticate with the dashboard session cookie or a bearer token.

Details: none.

INVALID_CREDENTIALS

Property	Value
Title	Invalid credentials
HTTP status	401
Category	auth
Retryable	never (do not retry; the request cannot succeed as sent)

Message: Invalid username or password.

Hint: Check the password; reset it with browserhive admin reset-password.

Cause: The login password did not match, or the account is locked out.

Resolution: Retry with the correct password or reset it from the CLI.

Details: none.

FORBIDDEN

Property	Value
Title	Forbidden
HTTP status	403
Category	auth
Retryable	never (do not retry; the request cannot succeed as sent)

Message: This action requires the '{scope}' scope.

Hint: Use a principal that holds the scope.

Cause: The principal lacks the scope the route or tool declares.

Resolution: Operators hold every scope; issue an operator token with the needed scope.

Details:

Field	Type	Required	Constraints
scope	string	yes	—

PASSWORD_CHANGE_REQUIRED

Property	Value
Title	Password change required
HTTP status	403
Category	auth
Retryable	after_operator (retry after an operator acts (unlock the vault, resolve a request, change policy))

Message: The seed password must be changed before continuing.

Hint: Change the password on the login screen.

Cause: The operator account still uses the generated seed password.

Resolution: Set a new password; the seed file is shredded afterwards.

Details: none.

BAD_CURRENT_PASSWORD

Property	Value
Title	Current password incorrect
HTTP status	400
Category	auth
Retryable	different_args (retry only with different arguments)

Message: The current password is incorrect.

Hint: Re-enter the current password.

Cause: The password-change request carried a wrong current password.

Resolution: Retry with the correct current password.

Details: none.

WEAK_PASSWORD

Property	Value
Title	Password too weak
HTTP status	400
Category	auth
Retryable	different_args (retry only with different arguments)

Message: The new password must be at least {min_length} characters long.

Hint: Choose a longer password.

Cause: The new password is shorter than the minimum length.

Resolution: Use at least the minimum number of characters.

Details:

Field	Type	Required	Constraints
min_length	integer	yes	—

Transport errors

Protocol-level failures of HTTP and WebSocket requests (validation, limits, conflicts).

Code	Title	HTTP	Retryable
ORIGIN_NOT_ALLOWED	Origin not allowed	403	never
HOST_NOT_ALLOWED	Host not allowed	421	never
RATE_LIMITED	Rate limited	429	backoff
PAYLOAD_TOO_LARGE	Payload too large	413	different_args
VALIDATION_FAILED	Validation failed	400	different_args
NOT_FOUND	Not found	404	never
METHOD_NOT_ALLOWED	Method not allowed	405	never
CONFLICT	Conflict	409	different_args
NOT_ACCEPTABLE	Not acceptable	406	different_args
WS_PROTOCOL_ERROR	WebSocket protocol error	400	never
WS_OVERLOADED	WebSocket overloaded	503	backoff

ORIGIN_NOT_ALLOWED

Property	Value
Title	Origin not allowed
HTTP status	403
Category	transport
Retryable	never (do not retry; the request cannot succeed as sent)

Message: The request Origin is not allowed.

Hint: Open the dashboard from the server URL itself.

Cause: A browser request carried an Origin that does not match the server (CSRF guard).

Resolution: Use the dashboard served by this BrowserHive; no cross-origin access is allowed.

Details: none.

HOST_NOT_ALLOWED

Property	Value
Title	Host not allowed
HTTP status	421
Category	transport
Retryable	never (do not retry; the request cannot succeed as sent)

Message: The request Host header is not allowed.

Hint: Address the server by the host it is bound to.

Cause: DNS-rebinding guard: the Host header does not match the bound host.

Resolution: Use the bound host or IP in the URL.

Details: none.

RATE_LIMITED

Property	Value
Title	Rate limited
HTTP status	429
Category	transport
Retryable	backoff (retry later with backoff)

Message: Too many requests. Retry after {retry_after_ms} ms.

Hint: Back off for the given interval.

Cause: The client exceeded the login or API rate limit.

Resolution: Wait for retry_after_ms and retry.

Details:

Field	Type	Required	Constraints
retry_after_ms	integer	yes	—

PAYLOAD_TOO_LARGE

Property	Value
Title	Payload too large
HTTP status	413
Category	transport
Retryable	different_args (retry only with different arguments)

Message: The request body exceeds the limit of {limit_bytes} bytes.

Hint: Send a smaller body.

Cause: The body is larger than the route’s limit.

Resolution: Reduce the payload size.

Details:

Field	Type	Required	Constraints
limit_bytes	integer	yes	—

VALIDATION_FAILED

Property	Value
Title	Validation failed
HTTP status	400
Category	transport
Retryable	different_args (retry only with different arguments)

Message: The request failed validation.

Hint: Each issue names the field and what is wrong.

Cause: Params, query or body did not match the route schema; unknown keys are errors.

Resolution: Fix the listed fields.

Details:

Field	Type	Required	Constraints
issues	object[]	yes	each item: keys path, message, code

NOT_FOUND

Property	Value
Title	Not found
HTTP status	404
Category	transport
Retryable	never (do not retry; the request cannot succeed as sent)

Message: The requested resource does not exist.

Hint: Check the path and id.

Cause: No route or resource matches the request.

Resolution: Consult /api/v1/docs for the route table.

Details: none.

METHOD_NOT_ALLOWED

Property	Value
Title	Method not allowed
HTTP status	405
Category	transport
Retryable	never (do not retry; the request cannot succeed as sent)

Message: The method is not allowed for this resource.

Hint: Use one of the allowed methods.

Cause: The route exists but not for this HTTP method.

Resolution: See details.allow and the Allow header.

Details:

Field	Type	Required	Constraints
allow	string[]	yes	—

CONFLICT

Property	Value
Title	Conflict
HTTP status	409
Category	transport
Retryable	different_args (retry only with different arguments)

Message: The resource changed since you last read it.

Hint: Reload the resource and retry with the current version.

Cause: An optimistic-concurrency check (If-Match/version) failed; the HTTP layer may use 412.

Resolution: Re-read, then resubmit with current_version.

Details:

Field	Type	Required	Constraints
current_version	integer	no	—

NOT_ACCEPTABLE

Property	Value
Title	Not acceptable
HTTP status	406
Category	transport
Retryable	different_args (retry only with different arguments)

Message: None of the requested media types is supported.

Hint: Ask for one of the supported types.

Cause: The Accept header lists no representation the route can produce.

Resolution: See details.supported.

Details:

Field	Type	Required	Constraints
supported	string[]	yes	—

WS_PROTOCOL_ERROR

Property	Value
Title	WebSocket protocol error
HTTP status	400
Category	transport
Retryable	never (do not retry; the request cannot succeed as sent)

Message: The WebSocket client violated the protocol.

Hint: Reconnect with a compliant client.

Cause: Malformed envelope, unknown command, wrong protocol version, or a command before subscribe.

Resolution: Fix the client; the socket is closed with the code in spec 03 §6.4.

Details:

Field	Type	Required	Constraints
violations	string[]	yes	—

WS_OVERLOADED

Property	Value
Title	WebSocket overloaded
HTTP status	503
Category	transport
Retryable	backoff (retry later with backoff)

Message: The connection fell too far behind ({buffered_bytes} bytes buffered).

Hint: Reconnect and resubscribe with the last cursor.

Cause: Backpressure: the client did not drain the feed within the buffer bounds.

Resolution: Reconnect; the feed replays from your cursor or asks for a resync.

Details:

Field	Type	Required	Constraints
buffered_bytes	integer	yes	—

Audit outcomes

Recorded in the audit trail (vault log, attention history). Some are also returned inside a tool result.

Code	Title	HTTP	Retryable
ORIGIN_MISMATCH	Origin not on the allow-list	403	different_args
VAULT_FILL_AUTH_FAILED	Vault fill: authentication failed	500	never
VAULT_FILL_BLOCKED	Vault fill: blocked	500	never
VAULT_LIST_DENIED	Vault list: denied	500	never
ATTENTION_REJECTED	Attention: rejected	500	never
ATTENTION_TIMEOUT	Attention: timed out	500	never
ATTENTION_CANCELLED	Attention: cancelled	500	never

ORIGIN_MISMATCH

Property	Value
Title	Origin not on the allow-list
HTTP status	403
Category	audit
Retryable	different_args (retry only with different arguments)

Message: Origin '{page_origin}' is not on the allow-list for vault entry '{entry_name}'.

Hint: Navigate to an allowed origin before filling.

Cause: The page origin at fill time did not match the binding’s allowed origins.

Resolution: Fill only on the sites the operator bound the entry to.

Details:

Field	Type	Required	Constraints
page_origin	string	yes	—
entry_name	string	yes	—
allowed	string[]	yes	—

VAULT_FILL_AUTH_FAILED

Property	Value
Title	Vault fill: authentication failed
HTTP status	500
Category	audit
Retryable	never (do not retry; the request cannot succeed as sent)

Message: The vault fill completed but the site did not accept the credentials.

Hint: Classification of a returned vault_fill status; not an exception.

Cause: vault_fill returned auth_failed.

Resolution: Check the credential in the vault; nothing to retry automatically.

Details:

Field	Type	Required	Constraints
entry_name	string	yes	—

VAULT_FILL_BLOCKED

Property	Value
Title	Vault fill: blocked
HTTP status	500
Category	audit
Retryable	never (do not retry; the request cannot succeed as sent)

Message: The vault fill was blocked by policy.

Hint: Classification of a returned vault_fill status; not an exception.

Cause: vault_fill returned blocked (policy gate refused).

Resolution: See the reason; operators adjust bindings and policies.

Details:

Field	Type	Required	Constraints
entry_name	string	yes	—
reason	string	no	—

VAULT_LIST_DENIED

Property	Value
Title	Vault list: denied
HTTP status	500
Category	audit
Retryable	never (do not retry; the request cannot succeed as sent)

Message: The vault listing was denied for this session.

Hint: Classification of a returned vault_list_available status; not an exception.

Cause: vault_list_available returned no entries because policy denied the session.

Resolution: Operators adjust bindings and policies.

Details: none.

ATTENTION_REJECTED

Property	Value
Title	Attention: rejected
HTTP status	500
Category	audit
Retryable	never (do not retry; the request cannot succeed as sent)

Message: The attention request was rejected.

Hint: Classification of a returned request_attention status; not an exception.

Cause: The operator rejected the request, or the session closed while it was open.

Resolution: Read the returned message; continue or stop the task accordingly.

Details:

Field	Type	Required	Constraints
request_id	string	yes	—

ATTENTION_TIMEOUT

Property	Value
Title	Attention: timed out
HTTP status	500
Category	audit
Retryable	never (do not retry; the request cannot succeed as sent)

Message: Attention request timed out; the operator was not available to respond.

Hint: Classification of a returned request_attention status; not an exception.

Cause: Nobody resolved the request before its deadline.

Resolution: Retry later with a longer wait, or proceed without the operator.

Details:

Field	Type	Required	Constraints
request_id	string	yes	—

ATTENTION_CANCELLED

Property	Value
Title	Attention: cancelled
HTTP status	500
Category	audit
Retryable	never (do not retry; the request cannot succeed as sent)

Message: Client cancelled the attention request.

Hint: Classification of a returned request_attention status; not an exception.

Cause: The MCP client disconnected or sent notifications/cancelled.

Resolution: Nothing to do.

Details:

Field	Type	Required	Constraints
request_id	string	yes	—

Warnings

Non-fatal degradations recorded on a session or in the system events list; the operation continues.

Code	Title	HTTP	Retryable
EXECUTABLE_PATH_OVERRIDE	Executable path override	500	never
TRACE_START_FAILED	Trace could not start	500	never
TRACE_FINALIZE_FAILED	Trace could not be finalized	500	never
STEALTH_INIT_FAILED	Stealth init failed	500	never
BLOCKLIST_ROUTE_FAILED	Blocklist route failed	500	never
BYO_PROXY_UNSEEDED	BYO proxy: geo not seeded	500	never
VIEWPORT_OVERRIDE_UNASSERTED	Viewport override: display not asserted	500	never
IDENTITY_SEED_SAVE_FAILED	Identity seed not saved	500	never
REAP_DEAD_FAILED	Dead session reap failed	500	never
CDP_SESSION_LEAKED	CDP session leaked	500	never
SCREENSHOT_ARCHIVE_FAILED	Screenshot archive failed	500	never

EXECUTABLE_PATH_OVERRIDE

Property	Value
Title	Executable path override
HTTP status	500
Category	warning
Retryable	never (do not retry; the request cannot succeed as sent)

Message: {message}

Hint: Session warning: logged and broadcast on session:, never thrown.

Cause: A launch option set executablePath, which disables channel routing.

Resolution: Prefer channel; use executablePath only for custom builds.

Details:

Field	Type	Required	Constraints
session_id	string	yes	—
message	string	yes	—
details	object	no	additional keys allowed

TRACE_START_FAILED

Property	Value
Title	Trace could not start
HTTP status	500
Category	warning
Retryable	never (do not retry; the request cannot succeed as sent)

Message: {message}

Hint: Session warning: logged and broadcast on session:, never thrown.

Cause: Playwright tracing failed to start for the session; the session continues without a trace.

Resolution: Check disk space and the session directory permissions.

Details:

Field	Type	Required	Constraints
session_id	string	yes	—
message	string	yes	—
details	object	no	additional keys allowed

TRACE_FINALIZE_FAILED

Property	Value
Title	Trace could not be finalized
HTTP status	500
Category	warning
Retryable	never (do not retry; the request cannot succeed as sent)

Message: {message}

Hint: Session warning: logged and broadcast on session:, never thrown.

Cause: Stopping the trace failed or exceeded the 10 s cap at close.

Resolution: The trace may be incomplete; check disk space.

Details:

Field	Type	Required	Constraints
session_id	string	yes	—
message	string	yes	—
details	object	no	additional keys allowed

STEALTH_INIT_FAILED

Property	Value
Title	Stealth init failed
HTTP status	500
Category	warning
Retryable	never (do not retry; the request cannot succeed as sent)

Message: {message}

Hint: Session warning: logged and broadcast on session:, never thrown.

Cause: The CDP identity override could not be applied; the session runs with reduced stealth.

Resolution: Check the driver (Patchright/Playwright) version compatibility.

Details:

Field	Type	Required	Constraints
session_id	string	yes	—
message	string	yes	—
details	object	no	additional keys allowed

BLOCKLIST_ROUTE_FAILED

Property	Value
Title	Blocklist route failed
HTTP status	500
Category	warning
Retryable	never (do not retry; the request cannot succeed as sent)

Message: {message}

Hint: Session warning: logged and broadcast on session:, never thrown.

Cause: The network-level blocklist route could not be installed; tool-level enforcement still applies.

Resolution: Check the driver version; report if it repeats.

Details:

Field	Type	Required	Constraints
session_id	string	yes	—
message	string	yes	—
details	object	no	additional keys allowed

BYO_PROXY_UNSEEDED

Property	Value
Title	BYO proxy: geo not seeded
HTTP status	500
Category	warning
Retryable	never (do not retry; the request cannot succeed as sent)

Message: {message}

Hint: Session warning: logged and broadcast on session:, never thrown.

Cause: A caller-supplied proxy suppresses geo-derived identity because the exit location is unknown.

Resolution: Pass locale/timezoneId explicitly when using your own proxy.

Details:

Field	Type	Required	Constraints
session_id	string	yes	—
message	string	yes	—
details	object	no	additional keys allowed

VIEWPORT_OVERRIDE_UNASSERTED

Property	Value
Title	Viewport override: display not asserted
HTTP status	500
Category	warning
Retryable	never (do not retry; the request cannot succeed as sent)

Message: {message}

Hint: Session warning: logged and broadcast on session:, never thrown.

Cause: A caller-supplied viewport disables the display-coherence assertion of the fingerprint.

Resolution: Omit viewport to let the identity pick a coherent display.

Details:

Field	Type	Required	Constraints
session_id	string	yes	—
message	string	yes	—
details	object	no	additional keys allowed

IDENTITY_SEED_SAVE_FAILED

Property	Value
Title	Identity seed not saved
HTTP status	500
Category	warning
Retryable	never (do not retry; the request cannot succeed as sent)

Message: {message}

Hint: Session warning: logged and broadcast on session:, never thrown.

Cause: The .identity.json sidecar could not be written with the full profile.

Resolution: Check the auth-states directory permissions.

Details:

Field	Type	Required	Constraints
session_id	string	yes	—
message	string	yes	—
details	object	no	additional keys allowed

REAP_DEAD_FAILED

Property	Value
Title	Dead session reap failed
HTTP status	500
Category	warning
Retryable	never (do not retry; the request cannot succeed as sent)

Message: {message}

Hint: Session warning: logged and broadcast on session:, never thrown.

Cause: Closing a dead session raised; the sweeper will retry.

Resolution: No action; report if it repeats for the same session.

Details:

Field	Type	Required	Constraints
session_id	string	yes	—
message	string	yes	—
details	object	no	additional keys allowed

CDP_SESSION_LEAKED

Property	Value
Title	CDP session leaked
HTTP status	500
Category	warning
Retryable	never (do not retry; the request cannot succeed as sent)

Message: {message}

Hint: Session warning: logged and broadcast on session:, never thrown.

Cause: A CDP session was still attached when its page closed and had to be pruned late.

Resolution: No action; report if it repeats.

Details:

Field	Type	Required	Constraints
session_id	string	yes	—
message	string	yes	—
details	object	no	additional keys allowed

SCREENSHOT_ARCHIVE_FAILED

Property	Value
Title	Screenshot archive failed
HTTP status	500
Category	warning
Retryable	never (do not retry; the request cannot succeed as sent)

Message: {message}

Hint: Session warning: logged and broadcast on session:, never thrown.

Cause: A tool screenshot could not be written to the session directory.

Resolution: Check disk space and permissions.

Details:

Field	Type	Required	Constraints
session_id	string	yes	—
message	string	yes	—
details	object	no	additional keys allowed