mokosh/.planning/intel/constraints.md

Constraints (synthesized from SPEC)

All constraints below are sourced from Тз расширение фаза1.md (the SPEC, precedence 0). The DOC (README.md, precedence 1) is a confirming source where noted; where it diverges, the SPEC takes precedence per the ADR > SPEC > PRD > DOC rule.

Type taxonomy:

• nfr — non-functional requirement (performance, memory, latency, security)
• protocol — wire/file format or sequence contract
• schema — data structure contract
• api-contract — external API binding (Chrome extension APIs)

---

CON-ram-ceiling

• Source: Тз расширение фаза1.md §10 (acceptance criterion 9)
• Type: nfr
• Constraint: The extension's RAM footprint MUST NOT exceed 50 MB while running in the background.
• Component-level expected breakdown (SPEC §4, informative, not binding):
  • Video ring buffer: ~1.5–2 MB steady
  • rrweb buffer: ~1–3 MB
  • Event log: ~100–300 KB
  • Total steady-state expected component sum: ~2.6–5.3 MB
• DOC confirming source: README.md §"Критерии приёмки Фазы 1" — restates the 50 MB ceiling identically.
• DOC informational target: README.md §"Память" reports an expected steady-state of ~5–10 MB. This is a non-binding estimate, not a contradicting requirement; the binding ceiling remains 50 MB. See INGEST-CONFLICTS.md for the auto-resolved INFO entry.

---

CON-archive-export-latency

• Source: Тз расширение фаза1.md §10 (acceptance criterion 6)
• Type: nfr
• Constraint: From click to file landing in the Downloads folder MUST be < 5 seconds.
• DOC confirming source: README.md §"Критерии приёмки Фазы 1".

---

CON-video-window

• Source: Тз расширение фаза1.md §4.1
• Type: nfr / protocol
• Constraint: The video ring buffer MUST hold exactly the most recent 30 seconds of footage; older chunks are evicted after each new chunk arrives.
• Exception (DEC-009): the first chunk (WebM header) is exempt from eviction.

---

CON-rrweb-window

• Source: Тз расширение фаза1.md §4.2, §8
• Type: nfr / protocol
• Constraint: rrweb events MUST be retained for at most 10 minutes AND at most 5 000 events, whichever is tighter. Eviction sweep runs every 60 s on the time dimension; the 5 000-event cap is enforced on insert (oldest first out).

---

CON-event-log-window

• Source: Тз расширение фаза1.md §4.3
• Type: nfr / protocol
• Constraint: The user event log MUST be retained for at most 10 minutes.

---

CON-video-codec

• Source: Тз расширение фаза1.md §4.1
• Type: protocol
• Constraint: Video chunks MUST be encoded as video/webm; codecs=vp9 at a target bitrate of 400 000 bps (~3 MB/min raw). Chunk cadence (MediaRecorder timeslice) is 2000 ms.

---

CON-webm-header-retention

• Source: Тз расширение фаза1.md §4.1, §8
• Type: protocol
• Constraint: The first MediaRecorder chunk (WebM container header) MUST be retained in the buffer indefinitely; the assembled last_30sec.webm MUST remain playable in a browser.

---

CON-tab-capture-binding

• Source: Тз расширение фаза1.md §8
• Type: api-contract
• Constraint: chrome.tabCapture operates only on the active tab. On tab activation change, the recorder MUST re-attach to the new active tab. First invocation requires a user gesture.

RETIRED (Phase 01-stabilize-video-pipeline, 2026-05-15)

• RETIRED-BY: Phase 01 CONTEXT.md D-01 / D-A2
• Reason: This phase replaces chrome.tabCapture with navigator.mediaDevices.getDisplayMedia(). The new API is not active-tab-bound; the recorder captures a screen / window selected once via Chrome's native picker and continues across tab switches.
• Replacement: CON-display-capture-binding (below).

---

CON-service-worker-keepalive

• Source: Тз расширение фаза1.md §8
• Type: api-contract
• Constraint: MV3 Service Workers unload after ~30 s of inactivity. The extension MUST keep the worker alive via a chrome.alarms alarm firing every 20 seconds.

RETIRED (Phase 01-stabilize-video-pipeline, 2026-05-15)

• RETIRED-BY: Phase 01 CONTEXT.md D-17 / D-A2
• Reason: This phase replaces alarms-driven keepalive with a long-lived chrome.runtime.connect port between offscreen and Service Worker. Port-message traffic resets the SW idle timer per Chrome 110+ semantics.
• Replacement: CON-display-capture-binding (binds the port-keepalive expectations alongside the new capture API).

---

CON-manifest-permissions

• Source: Тз расширение фаза1.md §7
• Type: api-contract / schema
• Constraint: manifest.json MUST declare exactly:

  {
    "permissions": [
      "tabCapture",
      "activeTab",
      "downloads",
      "scripting",
      "storage"
    ],
    "host_permissions": [
      "<all_urls>"
    ]
  }
  

---

CON-sensitive-data-masking

• Source: Тз расширение фаза1.md §4.2, §8
• Type: nfr (security / privacy)
• Constraint: Sensitive input fields MUST be masked in both rrweb snapshots and the event log. Specifically:
  • input[type=password] — value NEVER recorded; element MUST be masked in rrweb via maskInputSelector.
  • Any element with data-sensitive="true" — masked in rrweb via maskInputSelector.
  • The event logger MUST filter input events to drop password field values.

---

CON-archive-layout

• Source: Тз расширение фаза1.md §6
• Type: schema (file layout)
• Constraint: The exported ZIP MUST follow the layout in REQ-archive-layout (verbatim, four top-level entries: video/, rrweb/, logs/, screenshot.png, meta.json). Filename pattern: session_report_YYYY-MM-DD_HH-MM-SS.zip.

---

CON-meta-json-schema

• Source: Тз расширение фаза1.md §6
• Type: schema
• Constraint: meta.json MUST conform to the verbatim schema in REQ-meta-json-schema. All listed fields are required.

---

CON-event-log-schema

• Source: Тз расширение фаза1.md §4.3
• Type: schema
• Constraint: Each entry in events.json MUST conform to:

  {
    "timestamp": <epoch_ms>,
    "type": "click | input | navigation | error | network",
    "target": "<css_selector>",
    "value": "<value_or_masked>",
    "url": "<page_url>",
    "meta": {}
  }
  

---

CON-buffer-storage

• Source: Тз расширение фаза1.md §2
• Type: nfr
• Constraint: All Phase 1 buffers MUST live in memory only (Service Worker for video, Content Script for rrweb + event log). chrome.storage is permitted but MUST NOT be used to persist the rolling buffers.

---

CON-display-capture-binding

• Source: Phase 01 CONTEXT.md D-01..D-17, RESEARCH.md Patterns 1 & 5
• Type: api-contract
• Constraint: Video capture uses navigator.mediaDevices.getDisplayMedia() invoked once per session from the offscreen document with chrome.offscreen.Reason.DISPLAY_MEDIA. The Service Worker is kept alive by a long-lived chrome.runtime.connect({ name: 'video-keepalive' }) port opened by the offscreen, with traffic in both directions at a minimum cadence of 25 s and pre-emptive reconnect at 290 s.
• Replaces: CON-tab-capture-binding (RETIRED), CON-service-worker-keepalive (RETIRED).
• UX trade-off: Chrome's permanent "Sharing your screen" indicator is shown while recording. SPEC §1 silent-operation property is intentionally relaxed.

---

CON-no-server-upload

• Source: Тз расширение фаза1.md §9
• Type: nfr (scope boundary)
• Constraint: Phase 1 MUST NOT transmit any captured data to a remote server. All export is local-only via chrome.downloads.