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Capture and payloads

An ordinary Cheetah command carries an object of parameters and eventually returns an object of application evidence. Keep that simple path when it fits. The facilities in this section exist for specific additional needs: observing the page immediately after an action, extracting trusted structure, moving supported large command values outside the WebSocket, protecting plaintext, changing Redis history storage, or coordinating several browser states as one run.

These are separate capabilities. Enabling one does not silently enable the others, and a marker or stored artifact does not inherit guarantees from a neighboring feature.

Choose the capability from the constraint

NeedFacilityWhat it changesWhat it does not prove
preserve the state immediately after one applied actionpost-command captureadds screenshot, DOM, and named parser evidence to that command's terminal payloadthat the page was globally stable or transactional
turn page HTML into versioned structured dataparser registry and client parser runnervalidates and delivers an exact trusted parser definitionthat an arbitrary client supports the engine or may inspect the page
fit supported large values within a command transport limitsigned payload referencestores the value in scoped history and sends a short-lived retrieval capabilityconfidentiality from the history or spill backend
keep selected command parameters unreadable to relay and storage infrastructureencrypted envelopeencrypts application values before normal client validation and executionkey distribution, rotation, or a complete response-encryption policy
keep a large retained payload outside its Redis Stream entryRedis history spillchanges backend placement while normal history reads rehydrate the messagethat a command will fit on the WebSocket
capture ordered states from one or more URLs as a named taskbrowser-capture serviceacquires browser workers and writes run records, artifacts, and a manifesta distributed queue or production retention service

The attachment point defines ownership

Post-command capture is part of the shared client execution pipeline. The platform-specific capture provider decides how to obtain a screenshot or DOM snapshot. Parser definitions begin in an optional server registry, travel as cache material, and execute in a compatible client.

Signed references connect an App node, history, a token signer, an authenticated HTTP retrieval route, and a client resolver. Encryption is client/application machinery and keeps key material outside the server. History spill is a property of the selected Redis history implementation and its external payload store. Browser-capture runs are a separate service around application commands, worker allocation, run storage, and artifact storage.

This is why there is no global enable_optional_services switch. Each facility has a different owner, lifecycle, failure path, and security boundary.

Read the exact contracts

Post-command capture defines when capture runs, the request and result shapes, parser failure behavior, and the size limits that affect returned evidence.

Parser registry and definitions covers immutable parser identity, Imprint v2 validation, inline and cache-aware delivery, browser preflight, and the current registry limitations.

References, encryption, and spill separates the three different payload problems and documents their processing order, security guarantees, retention behavior, and failure policies.

Browser capture runs documents the authenticated REST surface, worker binding, run and manifest models, status rules, artifact keys, and local-first limits of the optional service.

To build the extension assets required by the browser parser runner, follow Prepare browser parser capture.

Current maturity

Post-command browser capture, the Imprint parser path, payload references, client encryption helpers, and managed Redis-history spill have focused implementation and test coverage. They still require deliberate composition and deployment policy. The supplied parser registry is in-memory, and shared-tenancy composition currently excludes the built-in registry and payload offload until tenant-aware replacements are verified.

The browser-capture run service is a tested, synchronous, single-host first slice. Its run records can expire while local artifacts remain. Treat that limitation as part of the public contract, not as an operational detail to discover after deployment.

Post-command capture