Adding an LLM to a legacy system, stage by stage
Silent video: no voiceover, music or sound effects. This transcript repeats every on-screen word and describes each scene.
The film includes the topic label "LLMs in legacy systems", the note "Illustrative diagram", the TecnoStack logo and progress numbers 1, 2, 3, 4, 5, 6. Elements enter and leave during transitions; in portrait, the closing sign-off replaces the footer.

[0:00–0:05] Beat 1 of 6 (intro)
Kicker: LEGACY + AI
Headline: Add AI in controlled stages
Support: Keep a tested fallback
Diagram (decision paths): Routing; Existing path; LLM feature
Connections: Routing → Existing path; Routing → LLM feature
Highlighted: Routing
Scene: Branching diagram: Routing, Existing path, LLM feature. Connections: Routing to Existing path; Routing to LLM feature. Emphasis: Routing.

[0:05–0:10] Beat 2 of 6 (step1)
Kicker: 01
Headline: Inventory before building
Support: Keep one authoritative record
Diagram (evidence checklist): Read data; Data owner; Write paths; Off switch
Highlighted: Data owner
Scene: Comparison without scores: Read data, Data owner, Write paths, Off switch. Emphasis: Data owner.

[0:10–0:15] Beat 3 of 6 (step2)
Kicker: 02
Headline: Pilot read-only in isolation
Support: Use permitted data and reviewers
Diagram (flow): Test screen; Suggestion; Reviewer
Connections: Test screen → Suggestion; Suggestion → Reviewer
Highlighted: Reviewer
Scene: Flow: Test screen, Suggestion, Reviewer. Connections: Test screen to Suggestion; Suggestion to Reviewer. Emphasis: Reviewer.

[0:15–0:20] Beat 4 of 6 (step3)
Kicker: 03
Headline: Shadow with side effects disabled
Support: Review outcomes; protect data and capacity
Diagram (flow): Permitted input; Existing process; Shadow model; Review log
Connections: Permitted input → Existing process; Permitted input → Shadow model; Existing process → Review log; Shadow model → Review log
Highlighted: Shadow model
Scene: Flow: Permitted input, Existing process, Shadow model, Review log. Connections: Permitted input to Existing process; Permitted input to Shadow model; Existing process to Review log; Shadow model to Review log. Emphasis: Shadow model.

[0:20–0:25] Beat 5 of 6 (step4)
Kicker: 04
Headline: Expand only after passing gates
Support: Route changes do not undo effects
Diagram (timeline): Internal team; Small cohort; Wider cohorts; Retire by criteria
Connections: Internal team → Small cohort; Small cohort → Wider cohorts; Wider cohorts → Retire by criteria
Highlighted: Small cohort
Scene: Sequence: Internal team, Small cohort, Wider cohorts, Retire by criteria. Connections: Internal team to Small cohort; Small cohort to Wider cohorts; Wider cohorts to Retire by criteria. Emphasis: Small cohort.

[0:25–0:30] Beat 6 of 6 (close)
Kicker: TECNOSTACK
Headline: Add writes after separate validation
Support: Approve and authorize the exact action
Diagram (flow): Validated pilot; Human approval; Authorized API
Connections: Validated pilot → Human approval; Human approval → Authorized API
Highlighted: Authorized API
Sign-off: TecnoStack logo and tecnostack.com
Scene: Flow: Validated pilot, Human approval, Authorized API. Connections: Validated pilot to Human approval; Human approval to Authorized API. Emphasis: Authorized API.