diff --git a/docs/packer/agendas/Pack Wizard Studio Decision Propagation Agenda.md b/docs/packer/agendas/Pack Wizard Studio Decision Propagation Agenda.md
index 194c8cab..b91a4945 100644
--- a/docs/packer/agendas/Pack Wizard Studio Decision Propagation Agenda.md	
+++ b/docs/packer/agendas/Pack Wizard Studio Decision Propagation Agenda.md	
@@ -115,13 +115,34 @@ The packer contract should state clearly:
 
 The validation contract should be build-set-scoped and asset-oriented.
 
-It should return at least:
+Rules:
 
-- aggregate counts;
-- whether packing is allowed;
-- per-asset validation entries for assets in scope;
-- blocking diagnostics for default display;
-- enough detail for Studio drill-down without local recomputation.
+- validation runs on the same pack set used by summary:
+  `registered + included in build`;
+- validation is read-only, non-mutating, and snapshot-backed;
+- validation may reuse deep inspection or reconcile-grade logic internally;
+- a future deep-sync step may run before validation in the Studio flow, but validation itself still evaluates the packer snapshot;
+- only diagnostics marked `blocking` fail validation in the first wave;
+- if the returned per-asset list contains no blocking diagnostics, validation is green;
+- if the returned per-asset list contains any blocking diagnostics, validation is red and packing must not begin.
+
+The first-wave validation payload should prioritize the per-asset diagnostic list over aggregate data.
+
+Each validation item should expose:
+
+- asset id;
+- asset name;
+- asset path;
+- `lastModified`;
+- diagnostics.
+
+The diagnostics in this contract are blocking diagnostics only in the first wave.
+
+Aggregate data is secondary here.
+It may still exist, but it should not be treated as the primary UI payload because the Studio can derive aggregate views from the returned per-asset list if needed.
+
+Ordering is not a packer concern for the first-wave validation payload.
+The Studio may sort the returned items as it sees fit.
 
 ### Execution Recommendation
 
@@ -137,12 +158,75 @@ The final result should describe:
 - total assets packed;
 - duration or equivalent timing summary when available.
 
+### Summary Recommendation
+
+The first-wave summary contract is now closed as a fast snapshot-backed preflight view.
+
+Rules:
+
+- summary is read-only and non-mutating;
+- summary must return quickly from packer-owned snapshot state rather than from a deep recomputation pass;
+- packer is the only source of truth for the summary;
+- Studio must not reconstruct the summary from local navigator state;
+- unregistered assets and excluded assets do not appear as explicit summary items;
+- the summary does not anticipate emitted artifacts, companion artifacts, or `assets.pa` details in the first wave.
+
+The first-wave summary shape should contain:
+
+1. one aggregate count for the current pack set;
+2. one per-asset list for the current pack set.
+
+The aggregate is intentionally minimal in the first wave:
+
+- total included asset count is enough for now.
+
+Each per-asset summary entry should include at least:
+
+- asset name;
+- asset family;
+- min artifact count for that asset;
+- max artifact count for that asset;
+- `lastModified` as a `long`.
+
+`lastModified` is explicitly useful even if the packer cannot yet provide the final real value for every asset in the first implementation wave.
+The contract may expose `0` temporarily, but the field should already exist so the Studio can depend on the shape and later sort against real values.
+
+This per-asset list is the correct place for the developer-facing graphical occupancy preview per asset in the Studio shell.
+The aggregate should remain intentionally small.
+
 ## Open Questions
 
-1. Should validation result DTOs include all diagnostics in scope or only the subset relevant to the pack gate by default?
-2. Should the final pack result expose artifact paths, artifact labels, or both?
-3. Does the first-wave summary contract need companion artifact preview data, or is `assets.pa` plus counts enough before execution?
-4. Should the pack execution result carry timing directly, or should timing remain event-derived metadata?
+1. Should the final pack result expose artifact paths, artifact labels, or both?
+2. Should the pack execution result carry timing directly, or should timing remain event-derived metadata?
+
+## Resolved In This Agenda Wave
+
+The following points are now closed for `summary`:
+
+1. summary is read-only, non-mutating, and snapshot-backed;
+2. packer is the sole source of truth for summary data;
+3. unregistered and excluded assets do not appear as explicit summary entries;
+4. first-wave summary includes one aggregate count only:
+   total included asset count;
+5. first-wave summary also includes a per-asset list for the current pack set;
+6. each per-asset summary entry must expose:
+   asset name, asset family, min artifact count, max artifact count, and `lastModified`;
+7. `lastModified` may temporarily be `0` until full support exists, but the field should already exist in the public contract;
+8. summary does not anticipate companion artifacts or emitted artifact details in the first wave.
+
+The following points are now closed for `validation`:
+
+1. validation runs on the same `registered + included in build` set used by summary;
+2. validation is read-only, non-mutating, and snapshot-backed;
+3. only diagnostics marked `blocking` fail validation in the first wave;
+4. the primary validation payload is the per-asset diagnostics list, not the aggregate;
+5. each per-asset validation entry must expose:
+   asset id, asset name, asset path, `lastModified`, and diagnostics;
+6. the diagnostics returned by validation are blocking diagnostics only in the first wave;
+7. if the returned validation list contains no blocking diagnostics, validation is green;
+8. if the returned validation list contains any blocking diagnostics, validation is red and packing must not begin;
+9. payload ordering is not a packer responsibility in the first wave;
+10. a future deep-sync step may be added before validation in the Studio flow, but validation itself still evaluates the packer snapshot.
 
 ## Expected Follow-up
 
diff --git a/docs/packer/decisions/Pack Wizard Summary and Validation Contracts Decision.md b/docs/packer/decisions/Pack Wizard Summary and Validation Contracts Decision.md
new file mode 100644
index 00000000..81da6e4c
--- /dev/null
+++ b/docs/packer/decisions/Pack Wizard Summary and Validation Contracts Decision.md	
@@ -0,0 +1,174 @@
+# Pack Wizard Summary and Validation Contracts Decision
+
+Status: Accepted
+Date: 2026-03-20
+Domain Owner: `docs/packer`
+Cross-Domain Impact: `docs/studio`
+
+## Context
+
+The Studio `Pack Wizard` flow is now closed on the host side as a shell over packer-owned operations.
+
+That decision already fixed the outer boundary:
+
+- Studio is the shell;
+- packer owns summary, validation, pack execution, progress, and result semantics;
+- the wizard flow is phase-based;
+- the active pack set is the current `registered + included in build` set.
+
+On the packer side, the first remaining need is to close the public contract for `summary` and `validation` before the repository moves deeper into pack execution semantics.
+
+This decision consolidates the `summary` and `validation` part of the packer-side discussion from:
+
+- [`../agendas/Pack Wizard Studio Decision Propagation Agenda.md`](../agendas/Pack%20Wizard%20Studio%20Decision%20Propagation%20Agenda.md)
+- [`../../studio/decisions/Pack Wizard in Assets Workspace Decision.md`](../../studio/decisions/Pack%20Wizard%20in%20Assets%20Workspace%20Decision.md)
+
+The main question is not whether Studio should have these phases.
+That is already settled.
+The question is what the packer must expose as the authoritative public contract for those phases.
+
+## Decision
+
+The packer public contract for the `Pack Wizard` first wave adopts the following direction:
+
+1. `summary` and `validation` are distinct packer operations;
+2. both operations are read-only and non-mutating;
+3. both operations evaluate the same pack set:
+   `registered + included in build`;
+4. both operations are packer-owned and snapshot-backed;
+5. Studio consumes these packer responses and must not reconstruct equivalent semantics locally.
+
+## Adopted Constraints
+
+### 1. Summary Boundary
+
+- `summary` is a fast snapshot-backed preflight view;
+- `summary` must return from packer-owned snapshot state, not from a deep recomputation pass;
+- `summary` is not a build preview and must not imply that artifacts were emitted;
+- `summary` must not anticipate companion artifacts or emitted artifact details in the first wave;
+- `summary` must not include unregistered assets or excluded assets as explicit summary items.
+
+### 2. Summary Shape
+
+The first-wave `summary` contract contains:
+
+1. one aggregate count for the active pack set;
+2. one per-asset list for the active pack set.
+
+The aggregate is intentionally minimal in the first wave:
+
+- total included asset count is sufficient.
+
+Each per-asset summary entry must expose:
+
+- `assetId`
+- `assetName`
+- `assetFamily`
+- `minArtifactCount`
+- `maxArtifactCount`
+- `lastModified`
+
+`lastModified` is required in the public contract even if early implementations temporarily expose `0` until the real value is fully available per asset.
+
+The per-asset summary list is the intended payload for Studio-side graphical occupancy presentation.
+The aggregate remains deliberately small.
+
+### 3. Validation Boundary
+
+- `validation` evaluates the same active pack set as `summary`;
+- `validation` is read-only and non-mutating;
+- `validation` is snapshot-backed;
+- `validation` may internally reuse deep-inspection or reconcile-grade logic where needed;
+- a future Studio flow may add an explicit deep-sync step before validation, but validation itself still evaluates the packer snapshot boundary.
+
+### 4. Validation Failure Rule
+
+Only diagnostics marked `blocking` fail validation in the first wave.
+
+The rule is:
+
+- if no blocking diagnostics are returned for the active pack set, validation is green;
+- if any blocking diagnostics are returned for the active pack set, validation is red and packing must not begin.
+
+Warnings and non-blocking diagnostics are not part of the first-wave validation gate contract.
+
+### 5. Validation Shape
+
+The primary validation payload is the per-asset diagnostics list.
+
+Aggregate validation data may still exist, but it is secondary.
+The Studio may derive aggregate visual summaries from the per-asset list if useful.
+
+Each per-asset validation entry must expose:
+
+- `assetId`
+- `assetName`
+- `assetPath`
+- `lastModified`
+- `diagnostics`
+
+In the first wave, `diagnostics` in this contract means blocking diagnostics only.
+
+Ordering is not a packer responsibility in the first-wave validation payload.
+The Studio may sort the returned list as needed for presentation.
+
+## Why This Direction Was Chosen
+
+- It keeps `summary` and `validation` aligned with the existing request/result API style instead of inventing a special build-session protocol too early.
+- It keeps ownership where it belongs: the packer remains the source of truth for pack-set semantics and validation outcomes.
+- It gives Studio enough structured data to render the preflight and validation phases without recreating packer meaning.
+- It keeps the first-wave contract intentionally narrow so the repository can close `summary` and `validation` without prematurely locking the heavier `pack execution` semantics.
+- It gives the Studio enough per-asset detail to show useful occupancy and blocker views while keeping ordering and higher-level UI grouping on the host side.
+
+## Explicit Non-Decisions
+
+This decision does not yet define:
+
+- the final `pack execution` request/result contract;
+- emitted artifact reporting rules beyond what is already upstream in packer artifact specs;
+- the final event vocabulary for pack progress;
+- whether future validation payloads should include non-blocking diagnostics;
+- the final source for real `lastModified` values in every asset case;
+- runtime-ingestion and cartridge-facing conformance gates for actual artifact emission.
+
+## Implications
+
+- the current public API work for pack summary must expand beyond aggregate-only shape;
+- the current public API work for validation must expand beyond generic aggregate-first DTOs;
+- Studio `Pack Wizard` binding should evolve toward the per-asset summary and per-asset validation payloads defined here;
+- `summary` and `validation` can now be implemented independently of the heavier pack execution discussion;
+- the next packer discussion wave should focus primarily on execution semantics, artifact emission guarantees, and runtime/cartridge ingestion conformance.
+
+## Propagation Targets
+
+Specs:
+
+- [`../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)
+
+Plans:
+
+- [`../pull-requests/PR-28-pack-wizard-public-contracts-summary-validation-and-execution.md`](../pull-requests/PR-28-pack-wizard-public-contracts-summary-validation-and-execution.md)
+
+Cross-domain references:
+
+- [`../../studio/decisions/Pack Wizard in Assets Workspace Decision.md`](../../studio/decisions/Pack%20Wizard%20in%20Assets%20Workspace%20Decision.md)
+- [`../../studio/pull-requests/PR-11-pack-wizard-shell-and-packer-contract-consumption.md`](../../studio/pull-requests/PR-11-pack-wizard-shell-and-packer-contract-consumption.md)
+
+Implementation surfaces:
+
+- `prometeu-packer-api` summary and validation request/result DTOs
+- snapshot-backed pack summary query logic
+- snapshot-backed pack validation logic
+- Studio pack wizard summary and validation bindings
+
+## Validation Notes
+
+This decision is correctly implemented only when all of the following are true:
+
+- `summary` returns quickly from packer-owned snapshot state;
+- Studio does not reconstruct pack summary from navigator rows or local UI state;
+- `summary` returns only active pack-set items, not excluded or unregistered items;
+- `validation` returns blocking-diagnostic information per asset for the same active pack set;
+- a returned validation payload with any blocking diagnostics stops the wizard before pack execution;
+- the Studio may reorder the returned lists without changing packer semantics.
diff --git a/docs/packer/pull-requests/PR-29-pack-wizard-contract-adjustments-for-summary-and-validation.md b/docs/packer/pull-requests/PR-29-pack-wizard-contract-adjustments-for-summary-and-validation.md
new file mode 100644
index 00000000..3a17e1b2
--- /dev/null
+++ b/docs/packer/pull-requests/PR-29-pack-wizard-contract-adjustments-for-summary-and-validation.md
@@ -0,0 +1,93 @@
+# PR-29 Pack Wizard Contract Adjustments for Summary and Validation
+
+Domain Owner: `docs/packer`
+Cross-Domain Impact: `docs/studio`
+
+## Briefing
+
+The first public contract wave for the `Pack Wizard` has already landed in `prometeu-packer-api`, but the newly accepted packer decision for `summary` and `validation` closes a more specific shape than the initial API slice.
+
+In particular:
+
+- `summary` is no longer aggregate-only;
+- `summary` must expose a per-asset list for the active pack set;
+- `validation` is primarily a per-asset blocking-diagnostics list;
+- `validation` ordering is not a packer concern in the first wave;
+- aggregate validation data is secondary, not the center of the contract.
+
+This PR adjusts the public contracts so they match the accepted packer decision exactly.
+
+Reference decision:
+
+- [`../decisions/Pack Wizard Summary and Validation Contracts Decision.md`](../decisions/Pack%20Wizard%20Summary%20and%20Validation%20Contracts%20Decision.md)
+
+## Objective
+
+Align the public `prometeu-packer-api` contract for `summary` and `validation` with the accepted decision before deeper implementation work continues.
+
+## Dependencies
+
+- [`./PR-28-pack-wizard-public-contracts-summary-validation-and-execution.md`](./PR-28-pack-wizard-public-contracts-summary-validation-and-execution.md)
+- [`../decisions/Pack Wizard Summary and Validation Contracts Decision.md`](../decisions/Pack%20Wizard%20Summary%20and%20Validation%20Contracts%20Decision.md)
+- cross-domain reference:
+  [`../../studio/pull-requests/PR-11-pack-wizard-shell-and-packer-contract-consumption.md`](../../studio/pull-requests/PR-11-pack-wizard-shell-and-packer-contract-consumption.md)
+
+## Scope
+
+- adjust the public summary DTOs to include:
+  - aggregate included asset count
+  - per-asset summary list
+- adjust the public validation DTOs to make the per-asset blocking-diagnostics list the primary payload
+- add or rename DTOs as needed for:
+  - per-asset summary entry
+  - per-asset validation entry
+- keep `lastModified` present in both summary and validation item contracts
+- preserve the `read-only` and `non-mutating` nature of summary and validation
+- keep the Studio-facing API explicit and aligned with the accepted packer decision
+
+## Non-Goals
+
+- no runtime implementation of summary in `prometeu-packer-v1`
+- no runtime implementation of validation in `prometeu-packer-v1`
+- no `pack execution` contract changes unless strictly required by compile compatibility
+- no Studio implementation work in this PR
+
+## Execution Method
+
+1. Revisit the current `summary` and `validation` public DTOs in `prometeu-packer-api`.
+2. Expand the summary result shape so it carries:
+   - total included asset count
+   - per-asset summary entries
+3. Expand or reshape validation so the returned per-asset entries expose:
+   - asset id
+   - asset name
+   - asset path
+   - `lastModified`
+   - blocking diagnostics
+4. Keep validation aggregate data optional or secondary rather than the primary response focus.
+5. Preserve defensive-copy and validation patterns already used by public API records.
+6. Update Studio compile surfaces only as needed to keep the workspace consuming the revised contracts coherently.
+
+## Acceptance Criteria
+
+- the public summary contract matches the accepted decision shape
+- the public validation contract matches the accepted decision shape
+- `lastModified` exists in both per-asset summary and per-asset validation entries
+- validation payloads carry blocking diagnostics only in the first wave
+- compile succeeds across `prometeu-packer-api`, `prometeu-packer-v1`, and any directly affected Studio call sites
+
+## Validation
+
+- compile validation for `prometeu-packer-api`
+- compile validation for `prometeu-packer-v1`
+- compile validation for `prometeu-studio`
+- lightweight API tests if public message-shape tests already exist
+
+## Affected Artifacts
+
+- `docs/packer/decisions/**`
+- `docs/packer/pull-requests/**`
+- `prometeu-packer/prometeu-packer-api/src/main/java/p/packer/PackerWorkspaceService.java`
+- `prometeu-packer/prometeu-packer-api/src/main/java/p/packer/messages/**`
+- `prometeu-packer/prometeu-packer-api/src/main/java/p/packer/dtos/**`
+- `prometeu-studio/**` compile-level consumers of the summary/validation contracts
diff --git a/docs/packer/pull-requests/PR-30-pack-wizard-summary-snapshot-query.md b/docs/packer/pull-requests/PR-30-pack-wizard-summary-snapshot-query.md
new file mode 100644
index 00000000..f6403912
--- /dev/null
+++ b/docs/packer/pull-requests/PR-30-pack-wizard-summary-snapshot-query.md
@@ -0,0 +1,83 @@
+# PR-30 Pack Wizard Summary Snapshot Query
+
+Domain Owner: `docs/packer`
+Cross-Domain Impact: `docs/studio`
+
+## Briefing
+
+With the public contracts aligned, the next step is to actually produce the pack-wizard `summary` from the packer runtime snapshot.
+
+This is intentionally narrower than full pack execution.
+The goal is to expose a fast preflight summary of the active pack set so the Studio wizard can open on packer-owned state instead of local UI heuristics.
+
+Reference decision:
+
+- [`../decisions/Pack Wizard Summary and Validation Contracts Decision.md`](../decisions/Pack%20Wizard%20Summary%20and%20Validation%20Contracts%20Decision.md)
+
+## Objective
+
+Implement snapshot-backed `summary` for the pack wizard over the current `registered + included in build` set.
+
+## Dependencies
+
+- [`./PR-29-pack-wizard-contract-adjustments-for-summary-and-validation.md`](./PR-29-pack-wizard-contract-adjustments-for-summary-and-validation.md)
+- [`./PR-15-snapshot-backed-asset-query-services.md`](./PR-15-snapshot-backed-asset-query-services.md)
+- [`./PR-21-point-in-memory-snapshot-updates-after-write-commit.md`](./PR-21-point-in-memory-snapshot-updates-after-write-commit.md)
+- cross-domain reference:
+  [`../../studio/pull-requests/PR-11-pack-wizard-shell-and-packer-contract-consumption.md`](../../studio/pull-requests/PR-11-pack-wizard-shell-and-packer-contract-consumption.md)
+
+## Scope
+
+- implement `getPackWorkspaceSummary(...)` in `prometeu-packer-v1`
+- resolve the active pack set from the runtime snapshot:
+  `registered + included in build`
+- produce the aggregate included asset count
+- produce the per-asset summary list with:
+  - asset id
+  - asset name
+  - asset family
+  - min artifact count
+  - max artifact count
+  - `lastModified`
+- allow `lastModified = 0` in the first wave where the real value is not yet available
+- keep the query fast and snapshot-backed
+
+## Non-Goals
+
+- no validation logic in this PR
+- no pack execution logic in this PR
+- no emitted-artifact preview in summary
+- no inclusion of unregistered or excluded assets as explicit summary items
+
+## Execution Method
+
+1. Resolve the active runtime snapshot for the requested project.
+2. Filter the snapshot to the active pack set:
+   registered assets included in build.
+3. Derive one aggregate count from that filtered set.
+4. Map each included asset into the public per-asset summary DTO.
+5. Populate `minArtifactCount` and `maxArtifactCount` from the best currently available packer-owned summary facts.
+6. Populate `lastModified` from packer-owned runtime or filesystem facts when available, otherwise `0`.
+7. Return the summary result without performing deep validation or artifact planning.
+
+## Acceptance Criteria
+
+- `getPackWorkspaceSummary(...)` returns successfully from snapshot-backed state
+- the returned set contains only `registered + included in build` assets
+- the aggregate count matches the per-asset list size
+- per-asset summary entries expose the fields required by the accepted decision
+- the operation behaves as a fast read query rather than a deep recomputation path
+
+## Validation
+
+- packer unit tests for pack-set filtering
+- packer unit tests for summary DTO mapping
+- regression tests proving excluded and unregistered assets do not appear as summary items
+- Studio smoke validation proving the wizard summary can render from packer-owned data
+
+## Affected Artifacts
+
+- `prometeu-packer/prometeu-packer-v1/src/main/java/p/packer/services/**`
+- `prometeu-packer/prometeu-packer-v1/src/main/java/p/packer/models/**`
+- `prometeu-packer/prometeu-packer-v1/src/test/java/p/packer/services/**`
+- `prometeu-studio/**` wizard summary consumer surfaces if compile adaptation is needed
diff --git a/docs/packer/pull-requests/PR-31-pack-wizard-validation-snapshot-gate.md b/docs/packer/pull-requests/PR-31-pack-wizard-validation-snapshot-gate.md
new file mode 100644
index 00000000..135e1771
--- /dev/null
+++ b/docs/packer/pull-requests/PR-31-pack-wizard-validation-snapshot-gate.md
@@ -0,0 +1,91 @@
+# PR-31 Pack Wizard Validation Snapshot Gate
+
+Domain Owner: `docs/packer`
+Cross-Domain Impact: `docs/studio`
+
+## Briefing
+
+The `Pack Wizard` validation phase is not a generic workspace scan.
+It is a pack-set-specific gate over the current `registered + included in build` snapshot state.
+
+The accepted decision closes the first-wave semantics:
+
+- validation is read-only and snapshot-backed;
+- validation looks only at the active pack set;
+- only `blocking` diagnostics fail validation;
+- the primary payload is the per-asset blocking-diagnostics list.
+
+This PR implements that gate in `prometeu-packer-v1`.
+
+Reference decision:
+
+- [`../decisions/Pack Wizard Summary and Validation Contracts Decision.md`](../decisions/Pack%20Wizard%20Summary%20and%20Validation%20Contracts%20Decision.md)
+
+## Objective
+
+Implement snapshot-backed pack validation that returns per-asset blocking diagnostics for the active pack set and decides whether packing may proceed.
+
+## Dependencies
+
+- [`./PR-29-pack-wizard-contract-adjustments-for-summary-and-validation.md`](./PR-29-pack-wizard-contract-adjustments-for-summary-and-validation.md)
+- [`./PR-30-pack-wizard-summary-snapshot-query.md`](./PR-30-pack-wizard-summary-snapshot-query.md)
+- [`./PR-15-snapshot-backed-asset-query-services.md`](./PR-15-snapshot-backed-asset-query-services.md)
+- cross-domain reference:
+  [`../../studio/pull-requests/PR-11-pack-wizard-shell-and-packer-contract-consumption.md`](../../studio/pull-requests/PR-11-pack-wizard-shell-and-packer-contract-consumption.md)
+
+## Scope
+
+- implement `validatePackWorkspace(...)` in `prometeu-packer-v1`
+- evaluate only the current `registered + included in build` set from the runtime snapshot
+- collect only `blocking` diagnostics for the first-wave validation payload
+- return per-asset validation entries with:
+  - asset id
+  - asset name
+  - asset path
+  - `lastModified`
+  - blocking diagnostics
+- make validation green when no blocking diagnostics are returned
+- make validation red when any blocking diagnostics are returned
+- keep aggregate validation data secondary to the per-asset list
+
+## Non-Goals
+
+- no pack execution in this PR
+- no non-blocking diagnostics in the first-wave validation payload
+- no packer-owned ordering contract for the returned validation list
+- no deep-sync orchestration in this PR beyond using the current snapshot boundary
+
+## Execution Method
+
+1. Resolve the current runtime snapshot for the requested project.
+2. Filter it to the active pack set:
+   `registered + included in build`.
+3. Gather diagnostics relevant to each asset in that set.
+4. Keep only diagnostics marked `blocking` for the first-wave validation response.
+5. Map each asset with blockers into the public per-asset validation DTO.
+6. Allow `lastModified = 0` temporarily where the real value is not yet available.
+7. Return validation as green when the per-asset blocker list is empty and red otherwise.
+
+## Acceptance Criteria
+
+- `validatePackWorkspace(...)` evaluates only the active pack set
+- only blocking diagnostics appear in the first-wave validation payload
+- validation succeeds when no blocking diagnostics are present
+- validation fails when any blocking diagnostics are present
+- per-asset validation entries expose the fields required by the accepted decision
+- Studio can stop before `Packing` using packer-owned validation alone
+
+## Validation
+
+- packer unit tests for pack-set filtering during validation
+- packer unit tests proving non-blocking diagnostics do not fail the first-wave validation
+- packer unit tests proving blocking diagnostics do fail validation
+- DTO-mapping tests for per-asset validation entries
+- Studio smoke validation proving the wizard blocks on returned blockers
+
+## Affected Artifacts
+
+- `prometeu-packer/prometeu-packer-v1/src/main/java/p/packer/services/**`
+- `prometeu-packer/prometeu-packer-v1/src/main/java/p/packer/models/**`
+- `prometeu-packer/prometeu-packer-v1/src/test/java/p/packer/services/**`
+- `prometeu-studio/**` validation consumer surfaces if compile adaptation is needed