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A Working Set Envelope wraps a bounded MRS-S fragment with task-adaptive context for focused agent operations. See: /MRS-Specification-RFC#7-working-set-envelope

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Design Principles

  • Agents read MRS-S — complete, human-auditable score fragments
  • Scopes use UUIDs — not measure numbers — for structural stability
  • Task-adaptive context — views tailored to the specific task, not fixed rings
  • Permissions via bundles — lane bundles grant appropriate modification rights

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Envelope Structure

(working-set
  :version 1.0
  :source-hash "sha256:a3f2c1b9e4d7..."
  
  :scope
    (:measures #uuid "018c3f40-002d-..." #uuid "018c3f40-0034-...")
    (:instruments [clarinet-bb])
    (:voices [v1])
  :display-hint (:measures 45 52)
  
  :bundle orchestrate
  :allowed-ops [create-event update-event delete-event create-span delete-span]
  
  :task "Add clarinet countermelody responding to violin theme"
  
  :constraints
    ((range clarinet-bb E3 C7)
     (avoid parallel-fifths violin-1))
  
  :content
    (meta
      :time 4/4
      :key C :mode minor
      :tempo 132)
    
    (instruments
      (instrument clarinet-bb :name "Clarinet in Bb" :abbr "Cl." 
                  :staves [treble] :transposition (down M2)))
    
    (measures
      (measure 
        :id #uuid "018c3f40-002d-..."
        :number 45
        :beat-start 487
        (clarinet-bb
          (v1))))  ; Empty — target for agent
    
    (spans)
  
  :context-views
    (context-view melodic-reference
      :instruments [violin-1]
      :measures #uuid "018c3f40-002d-..." #uuid "018c3f40-0034-..."
      :content
        (measures
          (measure :id #uuid "..." :number 45
            (violin-1
              (v1
                (: 0 G5.q :id #uuid "...")
                (: 1 A5.e :id #uuid "...")
                ...)))))
    
    (context-view harmonic-context
      :content
        (harmony-events
          (chord :measure #uuid "..." :beat 0 :symbol Cm :function i)
          (chord :measure #uuid "..." :beat 2 :symbol Fm :function iv)))
  
  :structural-index-ref "sha256:abc123..."
  
  :available-queries
    [:melodic-content :harmonic-analysis :orchestration-density])

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Envelope Fields

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Required Fields

FieldTypeDescription
:versiondecimalEnvelope version (1.0)
:source-hashstringSHA-256 hash of source state (conflict detection)
:scopescope-specWhat the agent may modify
:contentMRS-SThe score fragment (readable, target of ops)

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Scope Specification

:scope
  (:measures #uuid "..." #uuid "...")   ; UUID range (inclusive)
  (:instruments [clarinet-bb flute-1])  ; Instruments included
  (:voices [v1 v2])                     ; Optional: specific voices
:display-hint (:measures 45 52)         ; Human-readable, informational
Important: Scope uses UUIDs for structural stability. Display hints are for human orientation only — never used for structural reference.

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Permission Fields

FieldTypeDescription
:bundlekeywordLane bundle granting permissions
:allowed-opslistExplicit list of permitted operation types

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Optional Fields

FieldTypeDescription
:taskstringNatural language task description
:constraintslistValidation rules agent must satisfy
:context-viewslistTask-adaptive context views
:structural-index-refstringHash reference to structural index
:available-querieslistQueries agent may request

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Content Self-Containment

The :content of a Working Set Envelope MUST be parseable as standalone MRS-S:
  • Instrument definitions MUST be included
  • Time/key/tempo state at extraction start MUST be declared
  • Spans MUST have both endpoints within scope OR be marked with boundary markers
This enables validation of the content independent of the full score.

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Task-Adaptive Context Views

Context views provide task-relevant information beyond the edit scope. Unlike fixed “near/far” rings, views are selected and shaped for the specific task. See: Task-Adaptive Context Views

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View Types

View TypePurpose
melodic-referenceMelody the agent should respond to
harmonic-contextChord progression and key areas
orchestration-mapActive instruments and texture
phrase-structurePhrase boundaries and form
dynamics-profileDynamics trajectory
thematic-referencesThemes and motifs

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View Selection by Task

Task TypeTypical Views
Countermelodymelodic-reference, harmonic-context
Orchestrationorchestration-map, dynamics-profile
Dynamics passphrase-structure, dynamics-profile
Harmonizationmelodic-reference, phrase-structure

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Boundary-Crossing Spans

When a span crosses the envelope boundary: 
(slur
  :id #uuid "018c3f2c-..."
  :from #uuid "018c3f2a-..."    ; Inside scope
  :to #uuid "018c3f2b-..."      ; Outside scope
  :boundary-exit true)          ; Marks endpoint outside

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Boundary Rules

  • :boundary-entry true — span starts outside scope, ends inside
  • :boundary-exit true — span starts inside scope, ends outside
  • Both markers — span crosses through scope
Boundary-marked spans are read-only at their boundary endpoints. Agents MAY NOT modify :from, :to, or :events of boundary-marked spans.

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Available Queries

Agents may request additional context: 
:available-queries
  [:melodic-content    ; Request melody from specific instruments
   :harmonic-analysis  ; Request harmony analysis
   :orchestration-density ; Request texture information
   :phrase-boundaries  ; Request phrase structure
   :thematic-occurrences] ; Request theme locations
Query request (in agent response): 
(query-request
  :type melodic-content
  :instruments [oboe-1]
  :measures #uuid "..." #uuid "..."
  :reason "Need oboe line to avoid doubling")
The orchestrator may grant or deny queries based on scope and permissions.

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Constraints

Constraints specify rules that generated content must satisfy: 
:constraints
  ((range clarinet-bb E3 C7)           ; Notes within instrument range
   (avoid parallel-fifths violin-1)    ; Voice-leading rule
   (prefer chord-tones downbeats))     ; Style preference

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Constraint Types

TypeSyntaxDescription
Range(range <instrument> <low> <high>)Notes within range
Avoid(avoid <violation> <ref-part>?)Prevent voice-leading errors
Prefer(prefer <feature> <location>)Style preferences
Density(note-density <min> <max>)Notes per measure
Constraint violations are caught in the musical rules validation stage.