diff --git a/docs/packer/decisions/Concurrency, Observability, and Studio Adapter Boundary Decision.md b/docs/packer/decisions/Concurrency, Observability, and Studio Adapter Boundary Decision.md
new file mode 100644
index 00000000..3c2e0a53
--- /dev/null
+++ b/docs/packer/decisions/Concurrency, Observability, and Studio Adapter Boundary Decision.md	
@@ -0,0 +1,130 @@
+# Concurrency, Observability, and Studio Adapter Boundary Decision
+
+Status: Accepted
+Date: 2026-03-11
+Domain Owner: `docs/packer`
+Cross-Domain Impact: `docs/studio`
+
+## Context
+
+The production `prometeu-packer` track introduces two architectural seams that must not remain implicit:
+
+1. the packer will become the operational source of truth for asset summaries, diagnostics, mutation previews, and build lifecycle state;
+2. Studio will consume that operational model through adapters instead of reconstructing packer semantics locally;
+3. the event and concurrency model must stay coherent when the packer is integrated into the Studio `Assets` workspace and shell.
+
+Without an explicit decision, the repository risks drifting into duplicated semantics:
+
+- Studio deriving packer-facing summaries from filesystem heuristics;
+- Studio inventing lifecycle meaning not present in packer events;
+- concurrent mutation or build behavior becoming observable in inconsistent ways.
+
+## Decision
+
+The following direction is adopted:
+
+1. `prometeu-packer` is the semantic owner of asset operational state.
+2. Studio is a consumer and remapper of packer responses and events, not a competing source of packer truth.
+3. The baseline packer write policy is a `single-writer semantic lane per project`.
+4. Packer observability is packer-native and causality-preserving.
+5. Studio adapters may reshape packer data for UI presentation, but may not invent packer semantics, causal relationships, or final outcomes absent from packer responses/events.
+
+## Adopted Constraints
+
+### 1. Summary and Response Authority
+
+- asset `summary`, `details`, `diagnostics`, `preview`, and build/mutation lifecycle state originate in the packer;
+- Studio may use packer responses directly or remap them into view models;
+- Studio must not define an alternative packer summary model from direct filesystem inspection once the packer-backed path exists;
+- UI-oriented phrasing or grouping is allowed only as a remapping of packer-owned semantics.
+
+### 2. Concurrency Model
+
+- coordination is project-scoped;
+- unrelated projects are not forced into one global execution lane;
+- `read/read` may run concurrently when reads observe a coherent snapshot;
+- `read/write` must not expose torn intermediate state;
+- `write/write` on the same project is serialized;
+- `build/write` on the same project is serialized unless a future explicit transactional model supersedes this baseline;
+- preview generation may run outside the final commit-critical section when safe, but final apply/commit remains serialized.
+
+### 3. Event and Observability Model
+
+- the packer emits the authoritative event stream for asset operations;
+- each logical operation must carry a stable `operation_id`;
+- events within one operation must carry monotonic `sequence`;
+- baseline event payloads must preserve fields equivalent to:
+  - `project_id`
+  - `operation_id`
+  - `sequence`
+  - `kind`
+  - `timestamp`
+  - `summary`
+  - `progress` when applicable
+  - `affected_assets` when applicable
+- event ordering must remain causally coherent for one operation;
+- progress-like low-value repetition may be coalesced by sinks/adapters;
+- terminal lifecycle markers must remain individually observable.
+
+### 4. Studio Adapter Boundary
+
+- Studio adapts packer events into the existing Studio event bus and workspace models;
+- Studio may convert packer-native envelopes into Studio-native event types for shell/workspace consumption;
+- that adapter layer must remain translational, not semantic-authoritative;
+- Activity, progress, and staged mutation surfaces in Studio must reflect packer-native lifecycle, not replace it.
+
+## Why This Direction Was Chosen
+
+- It prevents split-brain semantics between packer and Studio.
+- It keeps packer behavior testable outside JavaFX.
+- It allows Studio UI iteration without moving domain rules into the UI layer.
+- It gives concurrency and observability one owner, which is necessary for deterministic mutation and build behavior.
+
+## Explicit Non-Decisions
+
+This decision does not define:
+
+- the final internal threading primitives or executor topology of `prometeu-packer`;
+- a watch daemon or continuous background worker model;
+- remote/shared cache coordination;
+- cross-project scheduling policy beyond allowing separate projects to coordinate independently;
+- final event transport beyond the local adapter/event sink model currently planned.
+
+## Implications
+
+- read adapters belong in the packer integration track, not in Studio-local filesystem services;
+- mutation preview/apply semantics belong in packer services and only map into Studio staged UI models;
+- Studio Activity and progress integration must preserve packer causality metadata, even if the UI renders a simplified form;
+- tests must verify both same-project write serialization and event ordering through the Studio adapter path.
+
+## Propagation Targets
+
+Specs:
+
+- [`../specs/5. Diagnostics, Operations, and Studio Integration Specification.md`](../specs/5.%20Diagnostics,%20Operations,%20and%20Studio%20Integration%20Specification.md)
+
+Plans:
+
+- [`../pull-requests/PR-04-workspace-scan-list-assets-and-studio-read-adapter.md`](../pull-requests/PR-04-workspace-scan-list-assets-and-studio-read-adapter.md)
+- [`../pull-requests/PR-05-sensitive-mutations-preview-apply-and-studio-write-adapter.md`](../pull-requests/PR-05-sensitive-mutations-preview-apply-and-studio-write-adapter.md)
+- [`../pull-requests/PR-09-event-lane-progress-and-studio-operational-integration.md`](../pull-requests/PR-09-event-lane-progress-and-studio-operational-integration.md)
+
+Cross-domain references:
+
+- [`../../studio/specs/4. Assets Workspace Specification.md`](../../studio/specs/4.%20Assets%20Workspace%20Specification.md)
+- [`../../studio/pull-requests/PR-05e-assets-staged-mutations-preview-and-apply.md`](../../studio/pull-requests/PR-05e-assets-staged-mutations-preview-and-apply.md)
+
+Implementation surfaces:
+
+- future `prometeu-packer` service contracts and event sink abstractions
+- Studio packer read/write/event adapters
+- Studio Activity/progress mapping code
+
+## Validation Notes
+
+The decision is correctly implemented only when all of the following are true:
+
+- the same packer operation can be replayed and observed without Studio inventing hidden state;
+- conflicting writes on one project cannot commit concurrently;
+- Activity/progress in Studio can be driven from packer-native events alone;
+- Studio summaries are either direct packer outputs or remapped packer outputs, never independent semantic recomputation.
diff --git a/docs/packer/decisions/README.md b/docs/packer/decisions/README.md
index ff2ef279..2b29b47a 100644
--- a/docs/packer/decisions/README.md
+++ b/docs/packer/decisions/README.md
@@ -2,7 +2,9 @@
 
 This directory contains packer decision records.
 
-There are currently no retained packer decision records.
+Retained packer decision records:
+
+- [`Concurrency, Observability, and Studio Adapter Boundary Decision.md`](./Concurrency,%20Observability,%20and%20Studio%20Adapter%20Boundary%20Decision.md)
 
 The first packer decision wave was already consolidated into:
 
diff --git a/docs/packer/pull-requests/PR-01-packer-project-bootstrap-and-module-boundaries.md b/docs/packer/pull-requests/PR-01-packer-project-bootstrap-and-module-boundaries.md
new file mode 100644
index 00000000..1976df9e
--- /dev/null
+++ b/docs/packer/pull-requests/PR-01-packer-project-bootstrap-and-module-boundaries.md
@@ -0,0 +1,63 @@
+# PR-01 Packer Project Bootstrap and Module Boundaries
+
+Domain Owner: `docs/packer`
+
+## Briefing
+
+Create the standalone `prometeu-packer` project and establish the production module boundaries required by the packer specs.
+
+This PR starts the implementation track without leaking packer behavior into Studio.
+
+## Objective
+
+Deliver a separate top-level `prometeu-packer` project with build wiring, package boundaries, test harness, and service-facing contracts that future PRs can implement incrementally.
+
+## Dependencies
+
+- [`../specs/1. Domain and Artifact Boundary Specification.md`](../specs/1.%20Domain%20and%20Artifact%20Boundary%20Specification.md)
+- [`../specs/5. Diagnostics, Operations, and Studio Integration Specification.md`](../specs/5.%20Diagnostics,%20Operations,%20and%20Studio%20Integration%20Specification.md)
+
+## Scope
+
+- add `prometeu-packer` as a separate project in the repository build
+- define the baseline package/module layout for:
+  - workspace and registry services
+  - declaration parsing and validation
+  - mutation preview/apply services
+  - build planning and artifact emission
+  - diagnostics and event reporting
+- define the public service contracts that Studio may consume through adapters
+- add baseline unit-test and fixture support for packer-only development
+
+## Non-Goals
+
+- no full workspace semantics yet
+- no asset build emission yet
+- no Studio UI changes beyond dependency wiring preparation
+
+## Execution Method
+
+1. Add `prometeu-packer` to Gradle settings and repository build wiring.
+2. Create baseline package namespaces and service interfaces.
+3. Establish a packer-owned test fixture layout for workspace samples and artifact assertions.
+4. Keep Studio integration contract-based so Studio does not depend on filesystem internals.
+
+## Acceptance Criteria
+
+- `prometeu-packer` exists as a separate build target
+- packer contracts compile without depending on Studio UI classes
+- future PRs can add implementations without restructuring the project root
+- packer test infrastructure is usable from the next PR onward
+
+## Validation
+
+- build graph includes `prometeu-packer`
+- baseline compile test for public contracts
+- fixture-loading smoke test in the new project
+
+## Affected Artifacts
+
+- `settings.gradle.kts`
+- `prometeu-packer/**`
+- repository build wiring
+- cross-domain reference: Studio adapter call sites that will later consume packer services
diff --git a/docs/packer/pull-requests/PR-02-workspace-init-registry-and-identity-foundation.md b/docs/packer/pull-requests/PR-02-workspace-init-registry-and-identity-foundation.md
new file mode 100644
index 00000000..a2fa88fc
--- /dev/null
+++ b/docs/packer/pull-requests/PR-02-workspace-init-registry-and-identity-foundation.md
@@ -0,0 +1,60 @@
+# PR-02 Workspace Init, Registry, and Identity Foundation
+
+Domain Owner: `docs/packer`
+
+## Briefing
+
+Implement the packer-owned workspace control model and registry authority in `prometeu-packer`.
+
+This PR turns the identity and workspace rules into executable code.
+
+## Objective
+
+Deliver `init_workspace`, registry load/store, identity allocation, and asset-root resolution as the stable foundation for all later packer operations.
+
+## Dependencies
+
+- [`./PR-01-packer-project-bootstrap-and-module-boundaries.md`](./PR-01-packer-project-bootstrap-and-module-boundaries.md)
+- [`../specs/1. Domain and Artifact Boundary Specification.md`](../specs/1.%20Domain%20and%20Artifact%20Boundary%20Specification.md)
+- [`../specs/2. Workspace, Registry, and Asset Identity Specification.md`](../specs/2.%20Workspace,%20Registry,%20and%20Asset%20Identity%20Specification.md)
+
+## Scope
+
+- implement `init_workspace`
+- create and validate `assets/.prometeu/index.json`
+- implement monotonic `asset_id` allocation and persisted allocator state
+- model `asset_uuid` allocation and persistence
+- implement root resolution utilities used by future read/write operations
+- define structural registry errors and missing-root behavior
+
+## Non-Goals
+
+- no `asset.json` semantic validation beyond what registry ownership requires
+- no Studio adapter yet
+- no build artifacts yet
+
+## Execution Method
+
+1. Implement packer-owned registry models and codecs.
+2. Add workspace bootstrap behavior for missing control directories.
+3. Enforce identity invariants around `asset_id`, `asset_uuid`, and root uniqueness.
+4. Expose internal services for lookup by `asset_id`, `asset_uuid`, and root path.
+
+## Acceptance Criteria
+
+- workspace initialization creates the minimum control structure deterministically
+- registry state round-trips without losing allocator data
+- duplicate or ambiguous identity-bearing entries fail clearly
+- relocation can later update root location without changing identity fields
+
+## Validation
+
+- unit tests for registry round-trip and allocator monotonicity
+- unit tests for duplicate-root and malformed-registry failures
+- workspace-init fixture test
+
+## Affected Artifacts
+
+- `prometeu-packer/**`
+- `assets/.prometeu/index.json` contract implementation
+- packer fixture workspaces
diff --git a/docs/packer/pull-requests/PR-03-asset-declaration-parsing-validation-and-details-contract.md b/docs/packer/pull-requests/PR-03-asset-declaration-parsing-validation-and-details-contract.md
new file mode 100644
index 00000000..c48ca4d7
--- /dev/null
+++ b/docs/packer/pull-requests/PR-03-asset-declaration-parsing-validation-and-details-contract.md
@@ -0,0 +1,65 @@
+# PR-03 Asset Declaration Parsing, Validation, and Details Contract
+
+Domain Owner: `docs/packer`
+
+## Briefing
+
+Implement strict `asset.json` parsing and the packer-side details contract used by both tooling and Studio.
+
+This PR converts the declaration spec into typed packer models and structured diagnostics.
+
+## Objective
+
+Deliver strict parse, schema/version checks, common field validation, and a `get_asset_details` response model that Studio can consume through an adapter.
+
+## Dependencies
+
+- [`./PR-02-workspace-init-registry-and-identity-foundation.md`](./PR-02-workspace-init-registry-and-identity-foundation.md)
+- [`../specs/3. Asset Declaration and Virtual Asset Contract Specification.md`](../specs/3.%20Asset%20Declaration%20and%20Virtual%20Asset%20Contract%20Specification.md)
+- [`../specs/6. Versioning, Migration, and Trust Model Specification.md`](../specs/6.%20Versioning,%20Migration,%20and%20Trust%20Model%20Specification.md)
+
+## Scope
+
+- parse and validate the common `asset.json` contract
+- validate required baseline fields:
+  - `schema_version`
+  - `name`
+  - `type`
+  - `inputs`
+  - `output`
+  - `preload`
+- emit structured diagnostics for parse, structural, and version errors
+- define the packer `get_asset_details` response model
+- preserve distinction between valid-orphan declarations and invalid declarations
+
+## Non-Goals
+
+- no full format-family payload encoding rules
+- no workspace scan aggregation yet
+- no mutation apply behavior yet
+
+## Execution Method
+
+1. Implement typed declaration models and strict decoding.
+2. Add common semantic validation and diagnostic mapping.
+3. Define details-response DTOs that preserve both declaration and diagnostic evidence.
+4. Back the contract with representative valid and invalid fixtures.
+
+## Acceptance Criteria
+
+- invalid declarations fail with actionable structured diagnostics
+- valid declarations produce stable typed models
+- `get_asset_details` can expose declaration, inputs, output, preload, and diagnostics cleanly
+- unsupported or malformed schema versions surface as explicit failures
+
+## Validation
+
+- fixture-driven parser tests
+- semantic validation tests for required fields
+- details-response tests for valid, orphan, and invalid declarations
+
+## Affected Artifacts
+
+- `prometeu-packer/**`
+- packer declaration fixtures
+- cross-domain reference: Studio asset details adapter inputs
diff --git a/docs/packer/pull-requests/PR-04-workspace-scan-list-assets-and-studio-read-adapter.md b/docs/packer/pull-requests/PR-04-workspace-scan-list-assets-and-studio-read-adapter.md
new file mode 100644
index 00000000..ec849a9b
--- /dev/null
+++ b/docs/packer/pull-requests/PR-04-workspace-scan-list-assets-and-studio-read-adapter.md
@@ -0,0 +1,61 @@
+# PR-04 Workspace Scan, List Assets, and Studio Read Adapter
+
+Domain Owner: `docs/packer`
+
+## Briefing
+
+Implement the read-side operational surface that turns a filesystem workspace into a packer-owned asset snapshot.
+
+This PR is the first explicit Studio integration step: Studio stops reading the workspace directly and starts consuming a packer response model through an adapter.
+
+## Objective
+
+Deliver `list_assets`, wire `get_asset_details` over real workspace scanning, and create the read adapter that maps packer responses to Studio workspace models.
+
+## Dependencies
+
+- [`./PR-03-asset-declaration-parsing-validation-and-details-contract.md`](./PR-03-asset-declaration-parsing-validation-and-details-contract.md)
+- [`../specs/2. Workspace, Registry, and Asset Identity Specification.md`](../specs/2.%20Workspace,%20Registry,%20and%20Asset%20Identity%20Specification.md)
+- [`../specs/5. Diagnostics, Operations, and Studio Integration Specification.md`](../specs/5.%20Diagnostics,%20Operations,%20and%20Studio%20Integration%20Specification.md)
+- cross-domain reference: [`../../studio/specs/4. Assets Workspace Specification.md`](../../studio/specs/4.%20Assets%20Workspace%20Specification.md)
+
+## Scope
+
+- implement workspace scanning for managed assets and orphan anchors
+- implement `list_assets`
+- finish real `get_asset_details` on top of packer services
+- distinguish managed-world structural issues from workspace hygiene findings in read responses
+- create the Studio read adapter from packer responses to the existing Studio asset workspace models
+- replace filesystem-specific read code in Studio with the adapter-backed path
+
+## Non-Goals
+
+- no sensitive mutation apply flows yet
+- no build pipeline yet
+- no event lane yet
+
+## Execution Method
+
+1. Scan `assets/` for anchored roots and reconcile against the registry.
+2. Produce a structured snapshot for list/details services.
+3. Implement a Studio adapter that maps packer DTOs into the Studio read model without embedding packer logic in JavaFX.
+4. Verify that Studio read behavior remains equivalent while packer becomes the source of truth.
+
+## Acceptance Criteria
+
+- `list_assets` returns managed and orphan assets coherently
+- Studio navigator and details surfaces can run on packer-backed read responses
+- registry authority remains visible in the mapped Studio state
+- invalid declarations and missing roots surface through structured diagnostics
+
+## Validation
+
+- packer tests for scan reconciliation and orphan detection
+- adapter tests for mapping list/details responses into Studio models
+- Studio smoke validation using the packer-backed read path
+
+## Affected Artifacts
+
+- `prometeu-packer/**`
+- `prometeu-studio/**` read adapters and service wiring
+- test fixtures shared across packer and Studio integration tests
diff --git a/docs/packer/pull-requests/PR-05-sensitive-mutations-preview-apply-and-studio-write-adapter.md b/docs/packer/pull-requests/PR-05-sensitive-mutations-preview-apply-and-studio-write-adapter.md
new file mode 100644
index 00000000..8a0d4f30
--- /dev/null
+++ b/docs/packer/pull-requests/PR-05-sensitive-mutations-preview-apply-and-studio-write-adapter.md
@@ -0,0 +1,78 @@
+# PR-05 Sensitive Mutations, Preview/Apply, and Studio Write Adapter
+
+Domain Owner: `docs/packer`
+
+## Briefing
+
+Implement the packer-owned preview/apply mutation services and route Studio staged mutations through a write adapter instead of local filesystem rules.
+
+This PR is where the current Studio staged mutation UI starts executing real packer semantics.
+
+## Objective
+
+Deliver structured preview/apply services for `register_asset`, `adopt_asset`, `forget_asset`, `remove_asset`, quarantine, and relocation, plus the Studio adapter that maps packer mutation responses into the existing staged mutation UI.
+
+## Dependencies
+
+- [`./PR-04-workspace-scan-list-assets-and-studio-read-adapter.md`](./PR-04-workspace-scan-list-assets-and-studio-read-adapter.md)
+- [`../specs/2. Workspace, Registry, and Asset Identity Specification.md`](../specs/2.%20Workspace,%20Registry,%20and%20Asset%20Identity%20Specification.md)
+- [`../specs/5. Diagnostics, Operations, and Studio Integration Specification.md`](../specs/5.%20Diagnostics,%20Operations,%20and%20Studio%20Integration%20Specification.md)
+- cross-domain reference: [`../../studio/pull-requests/PR-05e-assets-staged-mutations-preview-and-apply.md`](../../studio/pull-requests/PR-05e-assets-staged-mutations-preview-and-apply.md)
+
+## Scope
+
+- implement preview/apply service contracts for:
+  - `register_asset`
+  - `adopt_asset`
+  - `forget_asset`
+  - `remove_asset`
+  - `quarantine_asset`
+  - `relocate_asset`
+- preserve explicit distinction between:
+  - registry mutations
+  - workspace mutations
+  - blockers
+  - warnings
+  - safe fixes
+- implement mutation serialization rules so conflicting write flows do not race
+- implement the baseline single-writer semantic lane per project for sensitive mutation apply
+- create the Studio write adapter for staged mutation preview/apply
+- replace filesystem-only Studio mutation execution with packer-backed services
+
+## Non-Goals
+
+- no doctor implementation yet
+- no build artifact emission yet
+- no generic cross-workspace mutation framework
+
+## Execution Method
+
+1. Implement staged intent models and preview/apply response types in the packer.
+2. Implement mutation handlers on top of registry and workspace services.
+3. Serialize final mutation apply within a project-scoped write lane while keeping preview generation outside the commit-critical section when safe.
+4. Add a Studio adapter that converts packer mutation responses into the current staged preview model and forwards packer-native lifecycle events into the Studio event bus.
+5. Retire duplicated mutation semantics from Studio once the adapter path is stable.
+
+## Acceptance Criteria
+
+- sensitive mutations run through packer preview/apply services
+- Studio staged mutation UI no longer owns core mutation semantics
+- relocation preserves `asset_id` and `asset_uuid`
+- quarantine is explicit, previewable, and reversible in service semantics
+- mutation failures remain actionable and structured
+- conflicting mutation applies on the same project cannot commit concurrently
+- mutation lifecycle can be surfaced to Studio without Studio inventing semantic outcomes
+
+## Validation
+
+- packer tests for each sensitive mutation preview/apply path
+- packer concurrency tests for same-project conflicting writes
+- adapter tests for mapping packer responses into Studio preview models
+- adapter tests for forwarding packer mutation lifecycle events into Studio events
+- Studio smoke validation for preview/apply against the packer-backed path
+
+## Affected Artifacts
+
+- `prometeu-packer/**`
+- `prometeu-studio/**` mutation adapter and wiring
+- mutation fixture workspaces
diff --git a/docs/packer/pull-requests/PR-06-doctor-diagnostics-and-safe-fix-baseline.md b/docs/packer/pull-requests/PR-06-doctor-diagnostics-and-safe-fix-baseline.md
new file mode 100644
index 00000000..6271ec7a
--- /dev/null
+++ b/docs/packer/pull-requests/PR-06-doctor-diagnostics-and-safe-fix-baseline.md
@@ -0,0 +1,60 @@
+# PR-06 Doctor, Diagnostics, and Safe-Fix Baseline
+
+Domain Owner: `docs/packer`
+
+## Briefing
+
+Implement the baseline doctor and diagnostics model for the production packer.
+
+This PR is responsible for making the packer operationally useful beyond navigation and mutation flows.
+
+## Objective
+
+Deliver structured doctor execution with managed-world validation, expanded workspace hygiene scanning, and safe-fix preview/apply where baseline-safe.
+
+## Dependencies
+
+- [`./PR-05-sensitive-mutations-preview-apply-and-studio-write-adapter.md`](./PR-05-sensitive-mutations-preview-apply-and-studio-write-adapter.md)
+- [`../specs/5. Diagnostics, Operations, and Studio Integration Specification.md`](../specs/5.%20Diagnostics,%20Operations,%20and%20Studio%20Integration%20Specification.md)
+- [`../specs/6. Versioning, Migration, and Trust Model Specification.md`](../specs/6.%20Versioning,%20Migration,%20and%20Trust%20Model%20Specification.md)
+
+## Scope
+
+- implement managed-world structural validation
+- implement expanded workspace hygiene scanning
+- classify diagnostics by severity and blocking behavior
+- implement safe mechanical fix flows for baseline-safe cases only
+- expose doctor responses in structured form for Studio and CI consumption
+- define evidence and summaries suitable for Activity and inline diagnostics
+
+## Non-Goals
+
+- no silent destructive repair
+- no speculative auto-healing of relocational or delete scenarios
+- no final watch mode yet
+
+## Execution Method
+
+1. Implement diagnostic producers for registry, declaration, and workspace hygiene findings.
+2. Implement doctor request modes and safe-fix eligibility checks.
+3. Model doctor output as structured responses instead of terminal-only text.
+4. Connect safe-fix preview/apply behavior to the same safety rules used by mutation flows.
+
+## Acceptance Criteria
+
+- blocking and non-blocking diagnostics are clearly separated
+- doctor can report on both managed-world validity and broader hygiene issues
+- safe fixes only exist where the operation is explicitly low-risk
+- Studio and CI can consume the same doctor response model
+
+## Validation
+
+- fixture tests for structural errors and hygiene findings
+- tests for safe-fix eligibility and refusal paths
+- adapter tests for Studio diagnostic mapping
+
+## Affected Artifacts
+
+- `prometeu-packer/**`
+- cross-domain reference: Studio diagnostics and activity consumers
+- doctor fixtures and expected reports
diff --git a/docs/packer/pull-requests/PR-07-build-plan-determinism-and-cache-key-foundation.md b/docs/packer/pull-requests/PR-07-build-plan-determinism-and-cache-key-foundation.md
new file mode 100644
index 00000000..5da2383e
--- /dev/null
+++ b/docs/packer/pull-requests/PR-07-build-plan-determinism-and-cache-key-foundation.md
@@ -0,0 +1,62 @@
+# PR-07 Build Plan, Determinism, and Cache-Key Foundation
+
+Domain Owner: `docs/packer`
+
+## Briefing
+
+Implement the deterministic planning layer that normalizes validated assets into a stable build plan before artifact emission.
+
+This PR is the boundary between workspace semantics and runtime-facing artifact production.
+
+## Objective
+
+Deliver a deterministic build planner, canonical header model, preload derivation, and cache-key foundation that later emission and incremental work can trust.
+
+## Dependencies
+
+- [`./PR-06-doctor-diagnostics-and-safe-fix-baseline.md`](./PR-06-doctor-diagnostics-and-safe-fix-baseline.md)
+- [`../specs/4. Build Artifacts and Deterministic Packing Specification.md`](../specs/4.%20Build%20Artifacts%20and%20Deterministic%20Packing%20Specification.md)
+- [`../specs/5. Diagnostics, Operations, and Studio Integration Specification.md`](../specs/5.%20Diagnostics,%20Operations,%20and%20Studio%20Integration%20Specification.md)
+
+## Scope
+
+- validate build-eligible managed assets
+- derive deterministic asset ordering by increasing `asset_id`
+- build canonical header-side models for:
+  - `asset_table`
+  - `preload`
+- define payload planning slots and offset planning inputs
+- compute cache keys from validated effective inputs
+- emit deterministic in-memory build plans before writing files
+
+## Non-Goals
+
+- no final `assets.pa` file emission yet
+- no watch mode yet
+- no format-family semantic expansion beyond what current specs already define
+
+## Execution Method
+
+1. Normalize validated managed assets into a stable build plan representation.
+2. Implement canonical JSON serialization rules for header mirrors and planner assertions.
+3. Compute cache keys only from validated effective inputs.
+4. Add deterministic tests proving equivalent workspaces produce equivalent plans.
+
+## Acceptance Criteria
+
+- equivalent inputs produce equivalent build plans
+- asset ordering is independent from filesystem traversal order
+- preload derivation matches declaration state deterministically
+- cache-key inputs are explicit and reproducible
+
+## Validation
+
+- determinism tests with reordered filesystem fixtures
+- canonical-header serialization tests
+- cache-key stability tests
+
+## Affected Artifacts
+
+- `prometeu-packer/**`
+- build planning fixtures
+- future dependency for `build` service and event lane
diff --git a/docs/packer/pull-requests/PR-08-assets-pa-and-companion-artifact-emission.md b/docs/packer/pull-requests/PR-08-assets-pa-and-companion-artifact-emission.md
new file mode 100644
index 00000000..6e1702ca
--- /dev/null
+++ b/docs/packer/pull-requests/PR-08-assets-pa-and-companion-artifact-emission.md
@@ -0,0 +1,63 @@
+# PR-08 assets.pa and Companion Artifact Emission
+
+Domain Owner: `docs/packer`
+
+## Briefing
+
+Implement writer-side artifact emission on top of the deterministic build planner.
+
+This PR turns validated and planned build state into the published packer outputs.
+
+## Objective
+
+Deliver `build`, `assets.pa`, and the baseline companion artifacts with deterministic ordering and stable writer-side contracts.
+
+## Dependencies
+
+- [`./PR-07-build-plan-determinism-and-cache-key-foundation.md`](./PR-07-build-plan-determinism-and-cache-key-foundation.md)
+- [`../specs/1. Domain and Artifact Boundary Specification.md`](../specs/1.%20Domain%20and%20Artifact%20Boundary%20Specification.md)
+- [`../specs/4. Build Artifacts and Deterministic Packing Specification.md`](../specs/4.%20Build%20Artifacts%20and%20Deterministic%20Packing%20Specification.md)
+
+## Scope
+
+- implement the `build` service
+- emit `assets.pa`
+- emit:
+  - `build/asset_table.json`
+  - `build/preload.json`
+  - `build/asset_table_metadata.json`
+- implement canonical header serialization and file writing
+- implement payload-region offset materialization from the build plan
+- expose build summaries and applied-artifact metadata for Studio and CI
+
+## Non-Goals
+
+- no cartridge assembly
+- no shipper coupling
+- no speculative layout optimization beyond deterministic packing
+
+## Execution Method
+
+1. Convert the build plan into emitted artifact bytes and companion files.
+2. Preserve header authority and 1:1 mirror rules for companion JSON outputs.
+3. Add golden fixtures for emitted headers and companion artifacts.
+4. Keep runtime-facing semantics bounded to writer-side production rules already specified.
+
+## Acceptance Criteria
+
+- `build` produces `assets.pa` and companion artifacts deterministically
+- companion JSON outputs mirror the runtime header where required
+- emitted ordering and offsets follow the build plan contract
+- repeated equivalent builds do not drift
+
+## Validation
+
+- golden tests for `assets.pa` envelope and header bytes
+- golden tests for companion JSON mirrors
+- repeated-build determinism tests
+
+## Affected Artifacts
+
+- `prometeu-packer/**`
+- build output fixtures
+- CI artifact assertions
diff --git a/docs/packer/pull-requests/PR-09-event-lane-progress-and-studio-operational-integration.md b/docs/packer/pull-requests/PR-09-event-lane-progress-and-studio-operational-integration.md
new file mode 100644
index 00000000..fb2ca9b8
--- /dev/null
+++ b/docs/packer/pull-requests/PR-09-event-lane-progress-and-studio-operational-integration.md
@@ -0,0 +1,83 @@
+# PR-09 Event Lane, Progress, and Studio Operational Integration
+
+Domain Owner: `docs/packer`
+
+## Briefing
+
+Implement the packer event/reporting lane and bind the production packer service lifecycle into Studio operational surfaces.
+
+This PR is where Studio stops inferring operational history locally and starts reflecting packer-native lifecycle events.
+
+## Objective
+
+Deliver the structured packer event lane, progress reporting, and adapter/wiring so Studio Activity, progress, and refresh behavior align with real packer execution.
+
+## Dependencies
+
+- [`./PR-08-assets-pa-and-companion-artifact-emission.md`](./PR-08-assets-pa-and-companion-artifact-emission.md)
+- [`../specs/5. Diagnostics, Operations, and Studio Integration Specification.md`](../specs/5.%20Diagnostics,%20Operations,%20and%20Studio%20Integration%20Specification.md)
+- cross-domain reference: [`../../studio/specs/1. Studio Shell and Workspace Layout Specification.md`](../../studio/specs/1.%20Studio%20Shell%20and%20Workspace%20Layout%20Specification.md)
+- cross-domain reference: [`../../studio/specs/4. Assets Workspace Specification.md`](../../studio/specs/4.%20Assets%20Workspace%20Specification.md)
+
+## Scope
+
+- implement the initial structured event set:
+  - `asset_discovered`
+  - `asset_changed`
+  - `diagnostics_updated`
+  - `build_started`
+  - `build_finished`
+  - `cache_hit`
+  - `cache_miss`
+  - `preview_ready`
+  - `action_applied`
+  - `action_failed`
+  - `progress_updated`
+- define the baseline event envelope with fields equivalent to:
+  - `project_id`
+  - `operation_id`
+  - `sequence`
+  - `kind`
+  - `timestamp`
+  - `summary`
+  - `progress`
+  - `affected_assets`
+- define event publishing hooks across scan, doctor, mutation, and build flows
+- implement the Studio adapter from packer events to Studio event bus semantics
+- align global Activity and progress behavior with packer-native lifecycle updates
+
+## Non-Goals
+
+- no final watch daemon
+- no remote/shared cache orchestration
+- no UI redesign
+
+## Execution Method
+
+1. Add event publication points to read, mutation, doctor, and build services.
+2. Define a packer event sink abstraction so Studio is a consumer, not the owner, of the event model.
+3. Preserve operation causality with stable `operation_id` plus monotonic per-operation `sequence`.
+4. Map packer events into existing Studio Activity and progress surfaces through an adapter, with coalescing only for low-value repeated progress-like events.
+5. Verify that long-running work does not block UI interaction and that terminal lifecycle events remain individually visible.
+
+## Acceptance Criteria
+
+- packer emits structured lifecycle events across core operations
+- Studio Activity/progress can be driven from packer-native events
+- mutation and build flows no longer require Studio-local event invention
+- event ordering is coherent from the UI perspective
+- same-operation event ordering is preserved through the Studio adapter
+- adapters may remap event shapes, but do not invent causal relationships or semantic summaries absent from the packer event stream
+
+## Validation
+
+- packer event publication tests
+- adapter tests from packer events to Studio events
+- ordering/coalescing tests for progress-heavy operations and terminal lifecycle events
+- Studio smoke validation for Activity and progress during packer-backed operations
+
+## Affected Artifacts
+
+- `prometeu-packer/**`
+- `prometeu-studio/**` event adapter and wiring
+- integration fixtures for long-running operations
diff --git a/docs/packer/pull-requests/PR-10-versioning-migration-trust-and-production-gates.md b/docs/packer/pull-requests/PR-10-versioning-migration-trust-and-production-gates.md
new file mode 100644
index 00000000..6dd89c01
--- /dev/null
+++ b/docs/packer/pull-requests/PR-10-versioning-migration-trust-and-production-gates.md
@@ -0,0 +1,70 @@
+# PR-10 Versioning, Migration, Trust, and Production Gates
+
+Domain Owner: `docs/packer`
+
+## Briefing
+
+Finish the production track by hardening the packer against version skew, corrupted inputs, and unsupported artifacts, while installing CI and integration gates for the standalone project.
+
+This PR closes the packer implementation wave with production readiness checks rather than new feature surface.
+
+## Objective
+
+Deliver explicit version checks, migration ownership behavior, trust-boundary enforcement, and production test gates for `prometeu-packer` and its Studio integration path.
+
+## Dependencies
+
+- [`./PR-09-event-lane-progress-and-studio-operational-integration.md`](./PR-09-event-lane-progress-and-studio-operational-integration.md)
+- [`../specs/6. Versioning, Migration, and Trust Model Specification.md`](../specs/6.%20Versioning,%20Migration,%20and%20Trust%20Model%20Specification.md)
+- cross-domain reference: [`../../studio/specs/4. Assets Workspace Specification.md`](../../studio/specs/4.%20Assets%20Workspace%20Specification.md)
+
+## Scope
+
+- implement explicit version checking across:
+  - `asset.json`
+  - `index.json`
+  - packer-owned cache/control schemas
+  - `assets.pa` writer-side contract surfaces
+- implement supported-window failure behavior and migration reporting
+- enforce conservative trust checks before parse, validation, mutation, and build
+- add CI gates and end-to-end fixtures for:
+  - read flows
+  - mutation preview/apply flows
+  - doctor
+  - build
+  - Studio adapter integration
+- consolidate operational docs and production readiness notes for the packer project
+
+## Non-Goals
+
+- no plugin system
+- no artifact signing strategy
+- no remote registry or shared-cache product surface
+
+## Execution Method
+
+1. Add version and migration checks to all packer-owned artifact boundaries.
+2. Make unsupported-version and migration failures explicit and structured.
+3. Add end-to-end integration fixtures that exercise the standalone packer with the Studio adapter path.
+4. Install repository gates so production regressions fail before merge.
+
+## Acceptance Criteria
+
+- unsupported versions fail early and clearly
+- migration attempts and failures are visible to Studio and CI
+- packer trust boundaries are enforced before unsafe work proceeds
+- `prometeu-packer` has end-to-end production gates covering its declared service surface
+
+## Validation
+
+- version-compatibility and migration tests
+- malformed/untrusted input hardening tests
+- end-to-end integration tests across packer plus Studio adapter path
+- CI execution proving the packer project is gated independently
+
+## Affected Artifacts
+
+- `prometeu-packer/**`
+- repository CI/build configuration
+- `prometeu-studio/**` integration gates where the adapter path is exercised
+- packer learn/spec propagation targets after implementation
diff --git a/docs/packer/pull-requests/README.md b/docs/packer/pull-requests/README.md
index 2d6358af..6c3d0b79 100644
--- a/docs/packer/pull-requests/README.md
+++ b/docs/packer/pull-requests/README.md
@@ -55,3 +55,22 @@ Recommended additional sections:
 ## Review Rule
 
 A pull request may plan code and spec consequences, but it must not replace a missing decision record.
+
+## Production Sequence
+
+The current production track for the standalone `prometeu-packer` project is:
+
+1. [`PR-01-packer-project-bootstrap-and-module-boundaries.md`](./PR-01-packer-project-bootstrap-and-module-boundaries.md)
+2. [`PR-02-workspace-init-registry-and-identity-foundation.md`](./PR-02-workspace-init-registry-and-identity-foundation.md)
+3. [`PR-03-asset-declaration-parsing-validation-and-details-contract.md`](./PR-03-asset-declaration-parsing-validation-and-details-contract.md)
+4. [`PR-04-workspace-scan-list-assets-and-studio-read-adapter.md`](./PR-04-workspace-scan-list-assets-and-studio-read-adapter.md)
+5. [`PR-05-sensitive-mutations-preview-apply-and-studio-write-adapter.md`](./PR-05-sensitive-mutations-preview-apply-and-studio-write-adapter.md)
+6. [`PR-06-doctor-diagnostics-and-safe-fix-baseline.md`](./PR-06-doctor-diagnostics-and-safe-fix-baseline.md)
+7. [`PR-07-build-plan-determinism-and-cache-key-foundation.md`](./PR-07-build-plan-determinism-and-cache-key-foundation.md)
+8. [`PR-08-assets-pa-and-companion-artifact-emission.md`](./PR-08-assets-pa-and-companion-artifact-emission.md)
+9. [`PR-09-event-lane-progress-and-studio-operational-integration.md`](./PR-09-event-lane-progress-and-studio-operational-integration.md)
+10. [`PR-10-versioning-migration-trust-and-production-gates.md`](./PR-10-versioning-migration-trust-and-production-gates.md)
+
+Recommended dependency chain:
+
+`PR-01 -> PR-02 -> PR-03 -> PR-04 -> PR-05 -> PR-06 -> PR-07 -> PR-08 -> PR-09 -> PR-10`
diff --git a/docs/packer/specs/5. Diagnostics, Operations, and Studio Integration Specification.md b/docs/packer/specs/5. Diagnostics, Operations, and Studio Integration Specification.md
index 69290121..b712da6b 100644
--- a/docs/packer/specs/5. Diagnostics, Operations, and Studio Integration Specification.md	
+++ b/docs/packer/specs/5. Diagnostics, Operations, and Studio Integration Specification.md	
@@ -66,6 +66,24 @@ Operations must distinguish:
 
 This distinction is part of the service semantics and must be visible to the UI.
 
+## Concurrency Model
+
+The packer concurrency model is conservative and project-scoped.
+
+Rules:
+
+- observable correctness takes priority over speculative parallelism;
+- operations are coordinated per project workspace, not globally across unrelated projects;
+- Studio is a consumer of packer coordination results, not the owner of packer concurrency policy.
+
+### Baseline Operation Matrix
+
+- read/read may run concurrently when each read observes a coherent snapshot;
+- read/write must not expose torn intermediate state to consumers;
+- write/write on the same project is serialized;
+- build/write on the same project is serialized unless a future spec introduces an explicit transactional coordination model;
+- background observation may continue while a serialized write lane is active, but it must not publish misleading post-state before commit visibility.
+
 ## Preview/Apply Model
 
 Sensitive mutations use staged intent.
@@ -126,6 +144,40 @@ Rules:
 - background observation and reporting may be continuous;
 - conflicting sensitive mutations must not race arbitrarily;
 - observable mutation behavior remains coherent from the UI perspective.
+- the baseline write policy is a single-writer semantic lane per project;
+- preview generation may run outside the final commit section, but apply/commit remains serialized;
+- build and sensitive mutation apply must not interleave on the same project in a way that obscures final state;
+- cancellation or failure must leave the observable project state in a coherent post-operation condition.
+
+### Event Envelope
+
+Packer events must be structured enough for adapters to preserve causality and user-facing meaning.
+
+At minimum, each event must carry fields equivalent to:
+
+- `project_id` or workspace identity
+- `operation_id`
+- `sequence`
+- `kind`
+- `timestamp`
+- `summary`
+- `progress` when applicable
+- `affected_assets` when applicable
+
+Rules:
+
+- `operation_id` is stable for the full lifecycle of one logical operation;
+- `sequence` is monotonic within one operation;
+- adapters may remap event shapes for UI consumption, but must not invent causal relationships not present in packer events.
+
+### Event Ordering and Coalescing
+
+Rules:
+
+- events emitted for one operation must be observable in causal order;
+- repeated progress updates may be coalesced by adapters or sinks;
+- lifecycle boundaries such as preview-ready, apply-success, apply-failure, build-started, and build-finished must remain individually observable;
+- low-value repeated observation events must not drown out actionable failures or terminal state.
 
 ## Incremental and Watch Integration