Arc Skills / Configuration and change control
Assess the impact of a requirement change
Use Arc Skills to explain what a requirement change actually alters, then trace the consequences through recorded design and verification links. The output separates demonstrated effects, candidates needing investigation and checks that can remain unchanged.
Use this skill
Use Arc Skills to assess the impact of this requirement change.
Inputs:
- Original and proposed wording, IDs and revisions
- Change rationale and recorded design, interface and test links
- Current configuration and evidence
Return a clause comparison and an impact register with mechanism, evidence, owner and next action. Separate calculated effects from plausible effects. Preserve the source statements and identify missing decisions.What you provide and what you get
| What you have | How it is used | What you get |
|---|---|---|
| Two requirement revisions | Compare actor, condition, function and limits | A precise technical delta |
| Recorded relationships and configurations | Trace why a dependent artifact could be affected | Candidate impacts with evidence paths |
| Tests, results and owner decisions | Check coverage and applicability | Targeted actions and screened-out checks |
Changing a telemetry interval from 5 seconds to 2 seconds
Illustrative engineering example.
The proposed revision tightens the maximum interval between status messages. All numbers below belong to this example; no transmission energy or project power margin has been supplied.
REQ-21 rev A: During monitoring, the controller shall transmit a status message at intervals no greater than 5 s.
REQ-21 rev B proposal: During monitoring, the controller shall transmit a status message at intervals no greater than 2 s.
INT-05 rev C: minimum recorder capacity 0.25 status messages/s.
TEST-21 rev A: checks intervals against 5 s. Message format and voltage levels are unchanged.| Affected artifact | Recorded path | Mechanism and finding | Evidence / next action | Owner |
|---|---|---|---|---|
| REQ-21 | A → proposed B | Actor, mode and message unchanged; maximum interval tightens from 5 s to 2 s | Confirm the intended monitoring obligation | Requirement owner |
| INT-05 rev C | REQ-21 → telemetry exchange | Required rate floor rises from 0.2 to 0.5 messages/s; specified capacity 0.25 is below the new floor | Update the interface agreement or demonstrate additional capacity | Controller and recorder owners |
| TEST-21 rev A | REQ-21 → interval test | A 5 s acceptance limit cannot verify the proposed 2 s obligation | Revise acceptance and exercise the relevant load cases | Verification owner |
| Power budget | Telemetry → transmitter load | More messages may increase consumption; size of effect unknown | Obtain message energy and applicable operating duty cycle | Electrical owner |
| Voltage-level test | INT-05 → electrical evidence | No changed voltage parameter is supplied | Screen out pending confirmation that hardware and operating conditions remain applicable | Interface owner |
The required-rate calculation is 1/5 = 0.2 messages/s before and 1/2 = 0.5 messages/s after. This reveals a contract gap; it does not measure the recorder’s physical maximum throughput.
The test, interface contract and power budget have different next actions. Being linked to the changed requirement does not make every artifact invalid. A screened-out check still records the technical reason and configuration assumption.
Trace a mechanism, not just a connection
- Compare the exact statements and distinguish clarification from a changed obligation.
- Follow recorded allocations, interfaces, tests and evidence; explain the mechanism for each candidate.
- Calculate only effects whose inputs and equations are known. Keep power, thermal and timing assumptions visible.
- Recommend an owner action and verification scope for each affected aspect; preserve valid evidence where the reasoning supports it.
Questions about this task
Does every linked test need to run again?
No. The question is whether its tested behavior or configuration changed. An interval test is affected here; an unchanged electrical-level test may be reusable after checking applicability.
Sources and further reading
- NASA Systems Engineering Handbook: configuration management: Background on identifying configurations and controlling baseline changes.
References inspected on 3 October 2026. The worked output is an authored example using the stated inputs.