Arc Skills / Requirements

Identify duplicate requirements in a specification

Arc Skills compares controlled requirements by actor, object, condition, and limit rather than wording similarity alone. It returns candidate duplicate clusters and a reason to retain, consolidate, or leave each row open.

Use this skill

Use Arc Skills to identify duplicate or overlapping requirements in the supplied baseline.

Inputs:
- Controlled specification version with exact IDs, wording, and locators
- Glossary definitions, allocations, and source hierarchy
- Existing traces or independent stakeholder origins

Return candidate clusters with equivalence rationale, meaningful differences, and a review action.
Preserve every source trace. Propose consolidation only when actor, condition, response, and limit truly match

Set up the toolkit · Read the skill instructions

What you provide and what you get

Inputs and outputs
What you have	How it is used	What you get
Requirement baseline	Supplies exact actors, responses, and conditions	Candidate clusters
Definitions	Tests whether similar words are equivalent	Meaning verdict
Source traces	Protects distinct stakeholder origins	Consolidation proposal

Retention is not always retrieval

Illustrative engineering example.

Three current requirements describe stored images. The glossary defines retain as keeping bits; it does not define available or retrievable.

R-10: The recorder shall retain images for 30 days.
R-11: Stored images shall remain available for 30 days.
R-12: Images shall be retrievable for 30 days.

Retention is not always retrieval — illustrative output
Cluster member	Equivalence verdict	Difference / action
R-10	Reference retention duty	Keep pending source review; actor and duration are explicit.
R-11	Possible duplicate of R-10	Available could mean stored or accessible; glossary owner defines it.
R-12	Related, not proven duplicate	Retrievable may require an access path and response performance; retain until defined.

All three share a 30-day duration, but the verbs may impose different observable outcomes. Deleting R-12 based on a similarity score could remove an access obligation.

If the glossary makes R-11 equivalent to retention, a single controlled statement with both source traces may be enough. The consolidation remains a proposal; the baseline and stakeholder origins must be preserved until approved.

Compare meaning at the same level

Fix the baseline so old and current versions are not mixed.
Compare actor, object, start event, mode, action, duration, and exceptions.
Look up controlled meanings and independent source obligations.
Group only defensible equivalents; leave term-dependent pairs as possible duplicates.

Questions about this task

Does identical text mean one can be deleted?

Not automatically. Two source documents may independently require the same outcome, and both traces may need preservation.

Is a stricter requirement a duplicate?

It overlaps but may add a real constraint. Compare the actual pass conditions before consolidation.

Sources and further reading

NASA Systems Engineering Handbook: Lifecycle and requirements guidance; the example decisions are illustrative.