diff --git a/.gitignore b/.gitignore
index 543b12c..da63fd4 100644
--- a/.gitignore
+++ b/.gitignore
@@ -20,7 +20,6 @@ health.json
 
 # Go modules
 vendor/
-go.sum
 
 # Python
 __pycache__/
diff --git a/contracts/howl/SOURCE.md b/contracts/howl/SOURCE.md
new file mode 100644
index 0000000..c923494
--- /dev/null
+++ b/contracts/howl/SOURCE.md
@@ -0,0 +1,45 @@
+# Vendored `howl.*` contract schemas
+
+The five `.schema.json` files in this directory are vendored, byte-for-byte
+copies of the generated JSON Schema published by HowlDream. They are the
+authoritative shape of the `howl.*` ecosystem envelopes this repo consumes
+and produces (`howl.candidate/v1` in, `howl.assessment/v1` out).
+
+**Source repository:** https://github.com/howlcipher/howldream
+**Pinned commit:** `bd10b18b7182e5216b494d728d015dbbba9b32d0`
+**Source path:** `schemas/*.schema.json`
+**Vendored:** 2026-09-12
+
+## Why vendored, not fetched at build/runtime
+
+See `howldream`'s `schemas/README.md` for the full comparison of distribution
+models. Summary: all producing/consuming repositories are owned by the same
+org with full git access, so a pinned, vendored copy (re-vendored as a
+deliberate, visible diff) is the simplest architecture justified by current
+scale — no live network fetch, no new shared package/repo.
+
+## How to re-vendor
+
+```sh
+cp /path/to/howldream/schemas/howl.*.schema.json contracts/howl/
+```
+
+Then update the pinned commit above to the exact `howldream` commit the
+copied files came from. Re-vendoring is a deliberate act, not automatic —
+bumping the pin should be its own visible diff, so a schema change is never
+silently absorbed.
+
+## What this proves, and what it doesn't
+
+`contract_test.go` in this package validates real envelope fixtures against
+these vendored schemas using a pure-Go JSON Schema validator
+(`github.com/santhosh-tekuri/jsonschema/v5`) — **no Python, no `howldream`
+import, no network access at test time.** This is the cross-language contract
+test referenced in `howldream/issues.md` item 1: proof that the schema is
+useful to a consumer that has never seen HowlDream's Python implementation.
+
+As documented in `howldream`'s `AUTHORITY_INVARIANT.md`, schema validation
+proves an envelope is *shaped* correctly — it does not prove the envelope's
+claims are true. HowlFrame's own `apps/candidate_evaluator` is the runtime
+control that independently evaluates candidate claims; it does not trust a
+candidate's self-reported `trust`/`status`/`disposition` fields.
diff --git a/contracts/howl/contract_test.go b/contracts/howl/contract_test.go
new file mode 100644
index 0000000..7028674
--- /dev/null
+++ b/contracts/howl/contract_test.go
@@ -0,0 +1,151 @@
+// Cross-language contract test: proves the vendored howl.* JSON Schema is
+// genuinely useful to a consumer that has never seen HowlDream's Python
+// implementation. This test imports no Python, no `howldream` package, and
+// makes no network calls — only the local vendored schema files and this
+// pure-Go JSON Schema validator.
+package howl
+
+import (
+	"encoding/json"
+	"testing"
+
+	"github.com/santhosh-tekuri/jsonschema/v5"
+)
+
+// validExplorationResult is a representative, schema-conformant
+// howl.exploration_result/v1 envelope, including a nested candidate.
+const validExplorationResult = `{
+  "schema_version": "howl.exploration_result/v1",
+  "exploration_id": "exp-go-001",
+  "parent_request_id": "req-go-001",
+  "objective": "Explore alternative diagnostic strategies",
+  "originating_component": "howlplane",
+  "authority": {"type": "ADVISORY", "executable": false},
+  "candidates": [
+    {
+      "schema_version": "howl.candidate/v1",
+      "candidate_id": "cand-go-001",
+      "source_run_id": "run-go-001",
+      "parent_request_id": "req-go-001",
+      "objective": "Explore alternative diagnostic strategies",
+      "text": "IDEA: add a bounded retry with jitter",
+      "trust": "UNVERIFIED",
+      "status": "GENERATED",
+      "authority": {"type": "ADVISORY", "executable": false},
+      "provenance": {"run_id": "run-go-001", "producer_component": "howldream"}
+    }
+  ],
+  "verification_status": "UNVERIFIED",
+  "recommended_disposition": "DEFER",
+  "provenance": {"run_id": "run-go-001", "producer_component": "howldream"}
+}`
+
+func compileExplorationResult(t *testing.T) *jsonschema.Schema {
+	t.Helper()
+	schema, err := Compile(ExplorationResult)
+	if err != nil {
+		t.Fatalf("compile %s: %v", ExplorationResult, err)
+	}
+	return schema
+}
+
+// mutate returns a deep copy of validExplorationResult with the given
+// mutator applied to its decoded form, re-encoded to JSON.
+func mutate(t *testing.T, mutator func(env map[string]interface{})) []byte {
+	t.Helper()
+	var env map[string]interface{}
+	if err := json.Unmarshal([]byte(validExplorationResult), &env); err != nil {
+		t.Fatalf("unmarshal fixture: %v", err)
+	}
+	mutator(env)
+	out, err := json.Marshal(env)
+	if err != nil {
+		t.Fatalf("marshal mutated fixture: %v", err)
+	}
+	return out
+}
+
+func TestValidEnvelopeValidates(t *testing.T) {
+	schema := compileExplorationResult(t)
+	if err := ValidateJSON(schema, []byte(validExplorationResult)); err != nil {
+		t.Fatalf("expected valid envelope to validate, got: %v", err)
+	}
+}
+
+func TestMissingRequiredFieldFails(t *testing.T) {
+	schema := compileExplorationResult(t)
+	bad := mutate(t, func(env map[string]interface{}) {
+		delete(env, "objective")
+	})
+	if err := ValidateJSON(schema, bad); err == nil {
+		t.Fatal("expected missing required field 'objective' to fail validation")
+	}
+}
+
+func TestUnsupportedSchemaVersionFails(t *testing.T) {
+	schema := compileExplorationResult(t)
+	bad := mutate(t, func(env map[string]interface{}) {
+		env["schema_version"] = "howl.bogus/v99"
+	})
+	if err := ValidateJSON(schema, bad); err == nil {
+		t.Fatal("expected forged schema_version to fail validation")
+	}
+}
+
+func TestInvalidEnumFails(t *testing.T) {
+	schema := compileExplorationResult(t)
+	bad := mutate(t, func(env map[string]interface{}) {
+		env["verification_status"] = "VERIFIED"
+	})
+	if err := ValidateJSON(schema, bad); err == nil {
+		t.Fatal("expected out-of-enum verification_status to fail validation")
+	}
+}
+
+func TestForgedAuthorityExecutableFails(t *testing.T) {
+	schema := compileExplorationResult(t)
+	bad := mutate(t, func(env map[string]interface{}) {
+		env["authority"] = map[string]interface{}{"type": "ADVISORY", "executable": true}
+	})
+	if err := ValidateJSON(schema, bad); err == nil {
+		t.Fatal("expected authority.executable=true to fail validation")
+	}
+}
+
+func TestInjectedPrivilegedFieldFails(t *testing.T) {
+	schema := compileExplorationResult(t)
+	for _, field := range []string{"executor", "execution_capability", "approved", "bypass_review"} {
+		field := field
+		t.Run(field, func(t *testing.T) {
+			bad := mutate(t, func(env map[string]interface{}) {
+				env[field] = true
+			})
+			if err := ValidateJSON(schema, bad); err == nil {
+				t.Fatalf("expected injected privileged field %q to fail validation (additionalProperties: false)", field)
+			}
+		})
+	}
+}
+
+func TestNestedCandidateForgedTrustFails(t *testing.T) {
+	schema := compileExplorationResult(t)
+	bad := mutate(t, func(env map[string]interface{}) {
+		candidates := env["candidates"].([]interface{})
+		cand := candidates[0].(map[string]interface{})
+		cand["trust"] = "VERIFIED"
+	})
+	if err := ValidateJSON(schema, bad); err == nil {
+		t.Fatal("expected nested candidate with forged trust='VERIFIED' to fail validation")
+	}
+}
+
+func TestAllFiveVendoredSchemasCompile(t *testing.T) {
+	for _, name := range []string{Exploration, Candidate, Assessment, DevelopmentResult, ExplorationResult} {
+		name := name
+		t.Run(name, func(t *testing.T) {
+			if _, err := Compile(name); err != nil {
+				t.Fatalf("expected vendored schema %s to compile, got: %v", name, err)
+			}
+		})
+	}
+}
diff --git a/contracts/howl/howl.assessment.v1.schema.json b/contracts/howl/howl.assessment.v1.schema.json
new file mode 100644
index 0000000..9e1ecb3
--- /dev/null
+++ b/contracts/howl/howl.assessment.v1.schema.json
@@ -0,0 +1,196 @@
+{
+  "$defs": {
+    "ExplorationAuthority": {
+      "additionalProperties": false,
+      "description": "Explicit authority boundary. HowlDream artifacts cannot authorize execution.",
+      "properties": {
+        "executable": {
+          "const": false,
+          "default": false,
+          "title": "Executable",
+          "type": "boolean"
+        },
+        "type": {
+          "const": "ADVISORY",
+          "default": "ADVISORY",
+          "title": "Type",
+          "type": "string"
+        }
+      },
+      "title": "ExplorationAuthority",
+      "type": "object"
+    },
+    "Provenance": {
+      "additionalProperties": true,
+      "description": "Shared audit-trail metadata attached to every howl.* envelope.\n\nDeliberately open (extra=\"allow\"), unlike StrictModel: provenance is\ndescriptive audit metadata, not an authority or structural boundary, and\nproducers have historically attached ad hoc extra keys (e.g. request-\nspecific hashes). The named fields below are the canonical, cross-cutting\nconcepts every producer should populate; anything else stays as an\nunvalidated extra key rather than failing validation.\n\nConcepts deliberately NOT duplicated here because a dedicated top-level\nfield already covers them on the envelopes that need them: authority\nstate (`authority`), schema identity (`schema_version`), candidate/run\nlineage (`parent_request_id`, `source_run_id`, `candidate_id`,\n`descent_dag`), and per-envelope evaluation/verification state\n(`CandidateHandoff.status`, `CandidateAssessment.disposition`,\n`ExplorationResult.verification_status`).",
+      "properties": {
+        "created_at": {
+          "title": "Created At",
+          "type": "string"
+        },
+        "model_or_provider": {
+          "anyOf": [
+            {
+              "type": "string"
+            },
+            {
+              "type": "null"
+            }
+          ],
+          "default": null,
+          "title": "Model Or Provider"
+        },
+        "observation_kind": {
+          "anyOf": [
+            {
+              "enum": [
+                "SIMULATED",
+                "DETERMINISTIC",
+                "LIVE",
+                "EXTERNALLY_OBSERVED"
+              ],
+              "type": "string"
+            },
+            {
+              "type": "null"
+            }
+          ],
+          "default": null,
+          "title": "Observation Kind"
+        },
+        "producer_component": {
+          "anyOf": [
+            {
+              "type": "string"
+            },
+            {
+              "type": "null"
+            }
+          ],
+          "default": null,
+          "title": "Producer Component"
+        },
+        "producer_version": {
+          "anyOf": [
+            {
+              "type": "string"
+            },
+            {
+              "type": "null"
+            }
+          ],
+          "default": null,
+          "title": "Producer Version"
+        },
+        "run_id": {
+          "anyOf": [
+            {
+              "type": "string"
+            },
+            {
+              "type": "null"
+            }
+          ],
+          "default": null,
+          "title": "Run Id"
+        },
+        "transformations": {
+          "items": {
+            "type": "string"
+          },
+          "title": "Transformations",
+          "type": "array"
+        }
+      },
+      "title": "Provenance",
+      "type": "object"
+    }
+  },
+  "$id": "https://raw.githubusercontent.com/howlcipher/howldream/main/schemas/howl.assessment.v1.schema.json",
+  "$schema": "https://json-schema.org/draft/2020-12/schema",
+  "additionalProperties": false,
+  "description": "Downstream evaluation result from HowlFrame: howl.assessment/v1.",
+  "properties": {
+    "assessment_id": {
+      "maxLength": 100,
+      "minLength": 1,
+      "title": "Assessment Id",
+      "type": "string"
+    },
+    "authority": {
+      "$ref": "#/$defs/ExplorationAuthority"
+    },
+    "candidate_id": {
+      "maxLength": 200,
+      "minLength": 1,
+      "title": "Candidate Id",
+      "type": "string"
+    },
+    "confidence": {
+      "default": "LOW",
+      "enum": [
+        "LOW",
+        "MEDIUM",
+        "HIGH",
+        "UNKNOWN"
+      ],
+      "title": "Confidence",
+      "type": "string"
+    },
+    "contradictions": {
+      "items": {
+        "type": "string"
+      },
+      "title": "Contradictions",
+      "type": "array"
+    },
+    "disposition": {
+      "enum": [
+        "REJECT",
+        "UNRESOLVED",
+        "INVESTIGATE",
+        "ACCEPT_FOR_DEVELOPMENT"
+      ],
+      "title": "Disposition",
+      "type": "string"
+    },
+    "evidence": {
+      "items": {
+        "additionalProperties": true,
+        "type": "object"
+      },
+      "title": "Evidence",
+      "type": "array"
+    },
+    "limitations": {
+      "items": {
+        "type": "string"
+      },
+      "title": "Limitations",
+      "type": "array"
+    },
+    "provenance": {
+      "$ref": "#/$defs/Provenance"
+    },
+    "schema_version": {
+      "const": "howl.assessment/v1",
+      "default": "howl.assessment/v1",
+      "title": "Schema Version",
+      "type": "string"
+    },
+    "unresolved_claims": {
+      "items": {
+        "type": "string"
+      },
+      "title": "Unresolved Claims",
+      "type": "array"
+    }
+  },
+  "required": [
+    "assessment_id",
+    "candidate_id",
+    "disposition"
+  ],
+  "title": "HowlFrame Candidate Assessment (howl.assessment/v1)",
+  "type": "object"
+}
diff --git a/contracts/howl/howl.candidate.v1.schema.json b/contracts/howl/howl.candidate.v1.schema.json
new file mode 100644
index 0000000..449be7a
--- /dev/null
+++ b/contracts/howl/howl.candidate.v1.schema.json
@@ -0,0 +1,233 @@
+{
+  "$defs": {
+    "ExplorationAuthority": {
+      "additionalProperties": false,
+      "description": "Explicit authority boundary. HowlDream artifacts cannot authorize execution.",
+      "properties": {
+        "executable": {
+          "const": false,
+          "default": false,
+          "title": "Executable",
+          "type": "boolean"
+        },
+        "type": {
+          "const": "ADVISORY",
+          "default": "ADVISORY",
+          "title": "Type",
+          "type": "string"
+        }
+      },
+      "title": "ExplorationAuthority",
+      "type": "object"
+    },
+    "Provenance": {
+      "additionalProperties": true,
+      "description": "Shared audit-trail metadata attached to every howl.* envelope.\n\nDeliberately open (extra=\"allow\"), unlike StrictModel: provenance is\ndescriptive audit metadata, not an authority or structural boundary, and\nproducers have historically attached ad hoc extra keys (e.g. request-\nspecific hashes). The named fields below are the canonical, cross-cutting\nconcepts every producer should populate; anything else stays as an\nunvalidated extra key rather than failing validation.\n\nConcepts deliberately NOT duplicated here because a dedicated top-level\nfield already covers them on the envelopes that need them: authority\nstate (`authority`), schema identity (`schema_version`), candidate/run\nlineage (`parent_request_id`, `source_run_id`, `candidate_id`,\n`descent_dag`), and per-envelope evaluation/verification state\n(`CandidateHandoff.status`, `CandidateAssessment.disposition`,\n`ExplorationResult.verification_status`).",
+      "properties": {
+        "created_at": {
+          "title": "Created At",
+          "type": "string"
+        },
+        "model_or_provider": {
+          "anyOf": [
+            {
+              "type": "string"
+            },
+            {
+              "type": "null"
+            }
+          ],
+          "default": null,
+          "title": "Model Or Provider"
+        },
+        "observation_kind": {
+          "anyOf": [
+            {
+              "enum": [
+                "SIMULATED",
+                "DETERMINISTIC",
+                "LIVE",
+                "EXTERNALLY_OBSERVED"
+              ],
+              "type": "string"
+            },
+            {
+              "type": "null"
+            }
+          ],
+          "default": null,
+          "title": "Observation Kind"
+        },
+        "producer_component": {
+          "anyOf": [
+            {
+              "type": "string"
+            },
+            {
+              "type": "null"
+            }
+          ],
+          "default": null,
+          "title": "Producer Component"
+        },
+        "producer_version": {
+          "anyOf": [
+            {
+              "type": "string"
+            },
+            {
+              "type": "null"
+            }
+          ],
+          "default": null,
+          "title": "Producer Version"
+        },
+        "run_id": {
+          "anyOf": [
+            {
+              "type": "string"
+            },
+            {
+              "type": "null"
+            }
+          ],
+          "default": null,
+          "title": "Run Id"
+        },
+        "transformations": {
+          "items": {
+            "type": "string"
+          },
+          "title": "Transformations",
+          "type": "array"
+        }
+      },
+      "title": "Provenance",
+      "type": "object"
+    }
+  },
+  "$id": "https://raw.githubusercontent.com/howlcipher/howldream/main/schemas/howl.candidate.v1.schema.json",
+  "$schema": "https://json-schema.org/draft/2020-12/schema",
+  "additionalProperties": false,
+  "description": "Speculative candidate for cross-component evaluation: howl.candidate/v1.",
+  "properties": {
+    "assumptions": {
+      "items": {
+        "type": "string"
+      },
+      "title": "Assumptions",
+      "type": "array"
+    },
+    "authority": {
+      "$ref": "#/$defs/ExplorationAuthority"
+    },
+    "candidate_id": {
+      "maxLength": 200,
+      "minLength": 1,
+      "title": "Candidate Id",
+      "type": "string"
+    },
+    "claims": {
+      "items": {
+        "additionalProperties": true,
+        "type": "object"
+      },
+      "title": "Claims",
+      "type": "array"
+    },
+    "condition": {
+      "default": "dream",
+      "title": "Condition",
+      "type": "string"
+    },
+    "contradictions": {
+      "items": {
+        "type": "string"
+      },
+      "title": "Contradictions",
+      "type": "array"
+    },
+    "evidence_refs": {
+      "items": {
+        "type": "string"
+      },
+      "title": "Evidence Refs",
+      "type": "array"
+    },
+    "objective": {
+      "maxLength": 10000,
+      "minLength": 1,
+      "title": "Objective",
+      "type": "string"
+    },
+    "parent_request_id": {
+      "maxLength": 100,
+      "minLength": 1,
+      "title": "Parent Request Id",
+      "type": "string"
+    },
+    "provenance": {
+      "$ref": "#/$defs/Provenance"
+    },
+    "schema_version": {
+      "const": "howl.candidate/v1",
+      "default": "howl.candidate/v1",
+      "title": "Schema Version",
+      "type": "string"
+    },
+    "source_run_id": {
+      "maxLength": 100,
+      "minLength": 1,
+      "title": "Source Run Id",
+      "type": "string"
+    },
+    "status": {
+      "default": "GENERATED",
+      "enum": [
+        "GENERATED",
+        "CHALLENGED",
+        "LOCALLY_VERIFIED",
+        "FRAME_REVIEWED",
+        "UNRESOLVED",
+        "REJECTED"
+      ],
+      "title": "Status",
+      "type": "string"
+    },
+    "text": {
+      "maxLength": 50000,
+      "minLength": 1,
+      "title": "Text",
+      "type": "string"
+    },
+    "trust": {
+      "const": "UNVERIFIED",
+      "default": "UNVERIFIED",
+      "title": "Trust",
+      "type": "string"
+    },
+    "unresolved_issues": {
+      "items": {
+        "type": "string"
+      },
+      "title": "Unresolved Issues",
+      "type": "array"
+    },
+    "verified_constraints": {
+      "items": {
+        "type": "string"
+      },
+      "title": "Verified Constraints",
+      "type": "array"
+    }
+  },
+  "required": [
+    "candidate_id",
+    "source_run_id",
+    "parent_request_id",
+    "objective",
+    "text"
+  ],
+  "title": "HowlDream Candidate Handoff (howl.candidate/v1)",
+  "type": "object"
+}
diff --git a/contracts/howl/howl.development_result.v1.schema.json b/contracts/howl/howl.development_result.v1.schema.json
new file mode 100644
index 0000000..71f135f
--- /dev/null
+++ b/contracts/howl/howl.development_result.v1.schema.json
@@ -0,0 +1,201 @@
+{
+  "$defs": {
+    "ExplorationAuthority": {
+      "additionalProperties": false,
+      "description": "Explicit authority boundary. HowlDream artifacts cannot authorize execution.",
+      "properties": {
+        "executable": {
+          "const": false,
+          "default": false,
+          "title": "Executable",
+          "type": "boolean"
+        },
+        "type": {
+          "const": "ADVISORY",
+          "default": "ADVISORY",
+          "title": "Type",
+          "type": "string"
+        }
+      },
+      "title": "ExplorationAuthority",
+      "type": "object"
+    },
+    "Provenance": {
+      "additionalProperties": true,
+      "description": "Shared audit-trail metadata attached to every howl.* envelope.\n\nDeliberately open (extra=\"allow\"), unlike StrictModel: provenance is\ndescriptive audit metadata, not an authority or structural boundary, and\nproducers have historically attached ad hoc extra keys (e.g. request-\nspecific hashes). The named fields below are the canonical, cross-cutting\nconcepts every producer should populate; anything else stays as an\nunvalidated extra key rather than failing validation.\n\nConcepts deliberately NOT duplicated here because a dedicated top-level\nfield already covers them on the envelopes that need them: authority\nstate (`authority`), schema identity (`schema_version`), candidate/run\nlineage (`parent_request_id`, `source_run_id`, `candidate_id`,\n`descent_dag`), and per-envelope evaluation/verification state\n(`CandidateHandoff.status`, `CandidateAssessment.disposition`,\n`ExplorationResult.verification_status`).",
+      "properties": {
+        "created_at": {
+          "title": "Created At",
+          "type": "string"
+        },
+        "model_or_provider": {
+          "anyOf": [
+            {
+              "type": "string"
+            },
+            {
+              "type": "null"
+            }
+          ],
+          "default": null,
+          "title": "Model Or Provider"
+        },
+        "observation_kind": {
+          "anyOf": [
+            {
+              "enum": [
+                "SIMULATED",
+                "DETERMINISTIC",
+                "LIVE",
+                "EXTERNALLY_OBSERVED"
+              ],
+              "type": "string"
+            },
+            {
+              "type": "null"
+            }
+          ],
+          "default": null,
+          "title": "Observation Kind"
+        },
+        "producer_component": {
+          "anyOf": [
+            {
+              "type": "string"
+            },
+            {
+              "type": "null"
+            }
+          ],
+          "default": null,
+          "title": "Producer Component"
+        },
+        "producer_version": {
+          "anyOf": [
+            {
+              "type": "string"
+            },
+            {
+              "type": "null"
+            }
+          ],
+          "default": null,
+          "title": "Producer Version"
+        },
+        "run_id": {
+          "anyOf": [
+            {
+              "type": "string"
+            },
+            {
+              "type": "null"
+            }
+          ],
+          "default": null,
+          "title": "Run Id"
+        },
+        "transformations": {
+          "items": {
+            "type": "string"
+          },
+          "title": "Transformations",
+          "type": "array"
+        }
+      },
+      "title": "Provenance",
+      "type": "object"
+    }
+  },
+  "$id": "https://raw.githubusercontent.com/howlcipher/howldream/main/schemas/howl.development_result.v1.schema.json",
+  "$schema": "https://json-schema.org/draft/2020-12/schema",
+  "additionalProperties": false,
+  "description": "Deliberate sandbox prototype specification from HowlCreate: howl.development_result/v1.",
+  "properties": {
+    "architecture_proposal": {
+      "default": "",
+      "maxLength": 100000,
+      "title": "Architecture Proposal",
+      "type": "string"
+    },
+    "authority": {
+      "$ref": "#/$defs/ExplorationAuthority"
+    },
+    "development_id": {
+      "maxLength": 200,
+      "minLength": 1,
+      "title": "Development Id",
+      "type": "string"
+    },
+    "epistemic_status": {
+      "maxLength": 100,
+      "minLength": 1,
+      "title": "Epistemic Status",
+      "type": "string"
+    },
+    "execution_authority": {
+      "const": "NONE",
+      "default": "NONE",
+      "title": "Execution Authority",
+      "type": "string"
+    },
+    "idea": {
+      "additionalProperties": true,
+      "title": "Idea",
+      "type": "object"
+    },
+    "lineage": {
+      "additionalProperties": true,
+      "title": "Lineage",
+      "type": "object"
+    },
+    "origin": {
+      "default": "howldream",
+      "maxLength": 100,
+      "minLength": 1,
+      "title": "Origin",
+      "type": "string"
+    },
+    "parent_request_id": {
+      "maxLength": 100,
+      "minLength": 1,
+      "title": "Parent Request Id",
+      "type": "string"
+    },
+    "provenance": {
+      "$ref": "#/$defs/Provenance"
+    },
+    "sandbox_prototype_design": {
+      "additionalProperties": true,
+      "title": "Sandbox Prototype Design",
+      "type": "object"
+    },
+    "schema_version": {
+      "const": "howl.development_result/v1",
+      "default": "howl.development_result/v1",
+      "title": "Schema Version",
+      "type": "string"
+    },
+    "source_candidate_id": {
+      "maxLength": 200,
+      "minLength": 1,
+      "title": "Source Candidate Id",
+      "type": "string"
+    },
+    "test_specification": {
+      "items": {
+        "additionalProperties": true,
+        "type": "object"
+      },
+      "title": "Test Specification",
+      "type": "array"
+    }
+  },
+  "required": [
+    "development_id",
+    "source_candidate_id",
+    "parent_request_id",
+    "epistemic_status"
+  ],
+  "title": "HowlCreate Development Result (howl.development_result/v1)",
+  "type": "object"
+}
diff --git a/contracts/howl/howl.exploration.v1.schema.json b/contracts/howl/howl.exploration.v1.schema.json
new file mode 100644
index 0000000..387924b
--- /dev/null
+++ b/contracts/howl/howl.exploration.v1.schema.json
@@ -0,0 +1,283 @@
+{
+  "$defs": {
+    "EvidenceRef": {
+      "additionalProperties": false,
+      "description": "Evidence supplied to or extracted during exploration.",
+      "properties": {
+        "facts": {
+          "additionalProperties": {
+            "type": "string"
+          },
+          "title": "Facts",
+          "type": "object"
+        },
+        "id": {
+          "pattern": "^[a-zA-Z0-9_./-]{1,100}$",
+          "title": "Id",
+          "type": "string"
+        },
+        "text": {
+          "default": "",
+          "maxLength": 50000,
+          "title": "Text",
+          "type": "string"
+        }
+      },
+      "required": [
+        "id"
+      ],
+      "title": "EvidenceRef",
+      "type": "object"
+    },
+    "ExplorationAuthority": {
+      "additionalProperties": false,
+      "description": "Explicit authority boundary. HowlDream artifacts cannot authorize execution.",
+      "properties": {
+        "executable": {
+          "const": false,
+          "default": false,
+          "title": "Executable",
+          "type": "boolean"
+        },
+        "type": {
+          "const": "ADVISORY",
+          "default": "ADVISORY",
+          "title": "Type",
+          "type": "string"
+        }
+      },
+      "title": "ExplorationAuthority",
+      "type": "object"
+    },
+    "ExplorationBudget": {
+      "additionalProperties": false,
+      "description": "Finite bounded resource budget for speculative exploration.",
+      "properties": {
+        "local_only": {
+          "default": true,
+          "title": "Local Only",
+          "type": "boolean"
+        },
+        "max_candidates": {
+          "default": 6,
+          "maximum": 50,
+          "minimum": 1,
+          "title": "Max Candidates",
+          "type": "integer"
+        },
+        "max_duration_seconds": {
+          "default": 120,
+          "maximum": 600,
+          "minimum": 1,
+          "title": "Max Duration Seconds",
+          "type": "integer"
+        },
+        "max_tokens": {
+          "default": 512,
+          "maximum": 4096,
+          "minimum": 32,
+          "title": "Max Tokens",
+          "type": "integer"
+        },
+        "max_trials": {
+          "default": 1,
+          "maximum": 10,
+          "minimum": 1,
+          "title": "Max Trials",
+          "type": "integer"
+        },
+        "provider_allowlist": {
+          "items": {
+            "type": "string"
+          },
+          "title": "Provider Allowlist",
+          "type": "array"
+        }
+      },
+      "title": "ExplorationBudget",
+      "type": "object"
+    },
+    "Provenance": {
+      "additionalProperties": true,
+      "description": "Shared audit-trail metadata attached to every howl.* envelope.\n\nDeliberately open (extra=\"allow\"), unlike StrictModel: provenance is\ndescriptive audit metadata, not an authority or structural boundary, and\nproducers have historically attached ad hoc extra keys (e.g. request-\nspecific hashes). The named fields below are the canonical, cross-cutting\nconcepts every producer should populate; anything else stays as an\nunvalidated extra key rather than failing validation.\n\nConcepts deliberately NOT duplicated here because a dedicated top-level\nfield already covers them on the envelopes that need them: authority\nstate (`authority`), schema identity (`schema_version`), candidate/run\nlineage (`parent_request_id`, `source_run_id`, `candidate_id`,\n`descent_dag`), and per-envelope evaluation/verification state\n(`CandidateHandoff.status`, `CandidateAssessment.disposition`,\n`ExplorationResult.verification_status`).",
+      "properties": {
+        "created_at": {
+          "title": "Created At",
+          "type": "string"
+        },
+        "model_or_provider": {
+          "anyOf": [
+            {
+              "type": "string"
+            },
+            {
+              "type": "null"
+            }
+          ],
+          "default": null,
+          "title": "Model Or Provider"
+        },
+        "observation_kind": {
+          "anyOf": [
+            {
+              "enum": [
+                "SIMULATED",
+                "DETERMINISTIC",
+                "LIVE",
+                "EXTERNALLY_OBSERVED"
+              ],
+              "type": "string"
+            },
+            {
+              "type": "null"
+            }
+          ],
+          "default": null,
+          "title": "Observation Kind"
+        },
+        "producer_component": {
+          "anyOf": [
+            {
+              "type": "string"
+            },
+            {
+              "type": "null"
+            }
+          ],
+          "default": null,
+          "title": "Producer Component"
+        },
+        "producer_version": {
+          "anyOf": [
+            {
+              "type": "string"
+            },
+            {
+              "type": "null"
+            }
+          ],
+          "default": null,
+          "title": "Producer Version"
+        },
+        "run_id": {
+          "anyOf": [
+            {
+              "type": "string"
+            },
+            {
+              "type": "null"
+            }
+          ],
+          "default": null,
+          "title": "Run Id"
+        },
+        "transformations": {
+          "items": {
+            "type": "string"
+          },
+          "title": "Transformations",
+          "type": "array"
+        }
+      },
+      "title": "Provenance",
+      "type": "object"
+    }
+  },
+  "$id": "https://raw.githubusercontent.com/howlcipher/howldream/main/schemas/howl.exploration.v1.schema.json",
+  "$schema": "https://json-schema.org/draft/2020-12/schema",
+  "additionalProperties": false,
+  "description": "Standardized machine-readable exploration envelope: howl.exploration/v1.",
+  "properties": {
+    "authority": {
+      "$ref": "#/$defs/ExplorationAuthority"
+    },
+    "budget": {
+      "$ref": "#/$defs/ExplorationBudget"
+    },
+    "constraints": {
+      "items": {
+        "type": "string"
+      },
+      "maxItems": 50,
+      "title": "Constraints",
+      "type": "array"
+    },
+    "context_refs": {
+      "items": {
+        "type": "string"
+      },
+      "maxItems": 20,
+      "title": "Context Refs",
+      "type": "array"
+    },
+    "evidence_refs": {
+      "items": {
+        "$ref": "#/$defs/EvidenceRef"
+      },
+      "maxItems": 100,
+      "title": "Evidence Refs",
+      "type": "array"
+    },
+    "objective": {
+      "maxLength": 10000,
+      "minLength": 1,
+      "title": "Objective",
+      "type": "string"
+    },
+    "originating_component": {
+      "default": "howlplane",
+      "maxLength": 100,
+      "minLength": 1,
+      "title": "Originating Component",
+      "type": "string"
+    },
+    "parent_run_id": {
+      "anyOf": [
+        {
+          "type": "string"
+        },
+        {
+          "type": "null"
+        }
+      ],
+      "default": null,
+      "title": "Parent Run Id"
+    },
+    "provenance": {
+      "$ref": "#/$defs/Provenance"
+    },
+    "request_id": {
+      "pattern": "^[a-zA-Z0-9_-]{1,100}$",
+      "title": "Request Id",
+      "type": "string"
+    },
+    "requested_mode": {
+      "default": "dream",
+      "enum": [
+        "dream",
+        "nightmare",
+        "paired"
+      ],
+      "title": "Requested Mode",
+      "type": "string"
+    },
+    "risk_class": {
+      "default": "EXPLORATORY",
+      "maxLength": 50,
+      "title": "Risk Class",
+      "type": "string"
+    },
+    "schema_version": {
+      "const": "howl.exploration/v1",
+      "default": "howl.exploration/v1",
+      "title": "Schema Version",
+      "type": "string"
+    }
+  },
+  "required": [
+    "request_id",
+    "objective"
+  ],
+  "title": "HowlDream Exploration Request (howl.exploration/v1)",
+  "type": "object"
+}
diff --git a/contracts/howl/howl.exploration_result.v1.schema.json b/contracts/howl/howl.exploration_result.v1.schema.json
new file mode 100644
index 0000000..94ca697
--- /dev/null
+++ b/contracts/howl/howl.exploration_result.v1.schema.json
@@ -0,0 +1,467 @@
+{
+  "$defs": {
+    "CandidateHandoff": {
+      "additionalProperties": false,
+      "description": "Speculative candidate for cross-component evaluation: howl.candidate/v1.",
+      "properties": {
+        "assumptions": {
+          "items": {
+            "type": "string"
+          },
+          "title": "Assumptions",
+          "type": "array"
+        },
+        "authority": {
+          "$ref": "#/$defs/ExplorationAuthority"
+        },
+        "candidate_id": {
+          "maxLength": 200,
+          "minLength": 1,
+          "title": "Candidate Id",
+          "type": "string"
+        },
+        "claims": {
+          "items": {
+            "additionalProperties": true,
+            "type": "object"
+          },
+          "title": "Claims",
+          "type": "array"
+        },
+        "condition": {
+          "default": "dream",
+          "title": "Condition",
+          "type": "string"
+        },
+        "contradictions": {
+          "items": {
+            "type": "string"
+          },
+          "title": "Contradictions",
+          "type": "array"
+        },
+        "evidence_refs": {
+          "items": {
+            "type": "string"
+          },
+          "title": "Evidence Refs",
+          "type": "array"
+        },
+        "objective": {
+          "maxLength": 10000,
+          "minLength": 1,
+          "title": "Objective",
+          "type": "string"
+        },
+        "parent_request_id": {
+          "maxLength": 100,
+          "minLength": 1,
+          "title": "Parent Request Id",
+          "type": "string"
+        },
+        "provenance": {
+          "$ref": "#/$defs/Provenance"
+        },
+        "schema_version": {
+          "const": "howl.candidate/v1",
+          "default": "howl.candidate/v1",
+          "title": "Schema Version",
+          "type": "string"
+        },
+        "source_run_id": {
+          "maxLength": 100,
+          "minLength": 1,
+          "title": "Source Run Id",
+          "type": "string"
+        },
+        "status": {
+          "default": "GENERATED",
+          "enum": [
+            "GENERATED",
+            "CHALLENGED",
+            "LOCALLY_VERIFIED",
+            "FRAME_REVIEWED",
+            "UNRESOLVED",
+            "REJECTED"
+          ],
+          "title": "Status",
+          "type": "string"
+        },
+        "text": {
+          "maxLength": 50000,
+          "minLength": 1,
+          "title": "Text",
+          "type": "string"
+        },
+        "trust": {
+          "const": "UNVERIFIED",
+          "default": "UNVERIFIED",
+          "title": "Trust",
+          "type": "string"
+        },
+        "unresolved_issues": {
+          "items": {
+            "type": "string"
+          },
+          "title": "Unresolved Issues",
+          "type": "array"
+        },
+        "verified_constraints": {
+          "items": {
+            "type": "string"
+          },
+          "title": "Verified Constraints",
+          "type": "array"
+        }
+      },
+      "required": [
+        "candidate_id",
+        "source_run_id",
+        "parent_request_id",
+        "objective",
+        "text"
+      ],
+      "title": "CandidateHandoff",
+      "type": "object"
+    },
+    "DescentDAG": {
+      "additionalProperties": false,
+      "description": "Durable lineage DAG recording exploration descent and surviving handoffs.",
+      "properties": {
+        "edges": {
+          "items": {
+            "$ref": "#/$defs/DescentEdge"
+          },
+          "title": "Edges",
+          "type": "array"
+        },
+        "max_branching_factor": {
+          "default": 50,
+          "maximum": 200,
+          "minimum": 1,
+          "title": "Max Branching Factor",
+          "type": "integer"
+        },
+        "max_depth": {
+          "default": 20,
+          "maximum": 100,
+          "minimum": 1,
+          "title": "Max Depth",
+          "type": "integer"
+        },
+        "nodes": {
+          "additionalProperties": {
+            "$ref": "#/$defs/DescentNode"
+          },
+          "title": "Nodes",
+          "type": "object"
+        }
+      },
+      "title": "DescentDAG",
+      "type": "object"
+    },
+    "DescentEdge": {
+      "additionalProperties": false,
+      "description": "Directed derivation edge in the descent DAG.",
+      "properties": {
+        "relation": {
+          "maxLength": 100,
+          "minLength": 1,
+          "title": "Relation",
+          "type": "string"
+        },
+        "source": {
+          "maxLength": 200,
+          "minLength": 1,
+          "title": "Source",
+          "type": "string"
+        },
+        "target": {
+          "maxLength": 200,
+          "minLength": 1,
+          "title": "Target",
+          "type": "string"
+        }
+      },
+      "required": [
+        "source",
+        "target",
+        "relation"
+      ],
+      "title": "DescentEdge",
+      "type": "object"
+    },
+    "DescentNode": {
+      "additionalProperties": false,
+      "description": "Single node in the durable descent DAG.",
+      "properties": {
+        "created_at": {
+          "title": "Created At",
+          "type": "string"
+        },
+        "details": {
+          "additionalProperties": true,
+          "title": "Details",
+          "type": "object"
+        },
+        "label": {
+          "maxLength": 500,
+          "minLength": 1,
+          "title": "Label",
+          "type": "string"
+        },
+        "node_id": {
+          "maxLength": 200,
+          "minLength": 1,
+          "title": "Node Id",
+          "type": "string"
+        },
+        "node_type": {
+          "enum": [
+            "OBJECTIVE",
+            "BASELINE",
+            "DREAM_RUN",
+            "CANDIDATE",
+            "NIGHTMARE_CHALLENGE",
+            "WAKE_VERIFICATION",
+            "FRAME_ASSESSMENT",
+            "CREATE_PROJECT"
+          ],
+          "title": "Node Type",
+          "type": "string"
+        }
+      },
+      "required": [
+        "node_id",
+        "node_type",
+        "label"
+      ],
+      "title": "DescentNode",
+      "type": "object"
+    },
+    "ExplorationAuthority": {
+      "additionalProperties": false,
+      "description": "Explicit authority boundary. HowlDream artifacts cannot authorize execution.",
+      "properties": {
+        "executable": {
+          "const": false,
+          "default": false,
+          "title": "Executable",
+          "type": "boolean"
+        },
+        "type": {
+          "const": "ADVISORY",
+          "default": "ADVISORY",
+          "title": "Type",
+          "type": "string"
+        }
+      },
+      "title": "ExplorationAuthority",
+      "type": "object"
+    },
+    "Provenance": {
+      "additionalProperties": true,
+      "description": "Shared audit-trail metadata attached to every howl.* envelope.\n\nDeliberately open (extra=\"allow\"), unlike StrictModel: provenance is\ndescriptive audit metadata, not an authority or structural boundary, and\nproducers have historically attached ad hoc extra keys (e.g. request-\nspecific hashes). The named fields below are the canonical, cross-cutting\nconcepts every producer should populate; anything else stays as an\nunvalidated extra key rather than failing validation.\n\nConcepts deliberately NOT duplicated here because a dedicated top-level\nfield already covers them on the envelopes that need them: authority\nstate (`authority`), schema identity (`schema_version`), candidate/run\nlineage (`parent_request_id`, `source_run_id`, `candidate_id`,\n`descent_dag`), and per-envelope evaluation/verification state\n(`CandidateHandoff.status`, `CandidateAssessment.disposition`,\n`ExplorationResult.verification_status`).",
+      "properties": {
+        "created_at": {
+          "title": "Created At",
+          "type": "string"
+        },
+        "model_or_provider": {
+          "anyOf": [
+            {
+              "type": "string"
+            },
+            {
+              "type": "null"
+            }
+          ],
+          "default": null,
+          "title": "Model Or Provider"
+        },
+        "observation_kind": {
+          "anyOf": [
+            {
+              "enum": [
+                "SIMULATED",
+                "DETERMINISTIC",
+                "LIVE",
+                "EXTERNALLY_OBSERVED"
+              ],
+              "type": "string"
+            },
+            {
+              "type": "null"
+            }
+          ],
+          "default": null,
+          "title": "Observation Kind"
+        },
+        "producer_component": {
+          "anyOf": [
+            {
+              "type": "string"
+            },
+            {
+              "type": "null"
+            }
+          ],
+          "default": null,
+          "title": "Producer Component"
+        },
+        "producer_version": {
+          "anyOf": [
+            {
+              "type": "string"
+            },
+            {
+              "type": "null"
+            }
+          ],
+          "default": null,
+          "title": "Producer Version"
+        },
+        "run_id": {
+          "anyOf": [
+            {
+              "type": "string"
+            },
+            {
+              "type": "null"
+            }
+          ],
+          "default": null,
+          "title": "Run Id"
+        },
+        "transformations": {
+          "items": {
+            "type": "string"
+          },
+          "title": "Transformations",
+          "type": "array"
+        }
+      },
+      "title": "Provenance",
+      "type": "object"
+    }
+  },
+  "$id": "https://raw.githubusercontent.com/howlcipher/howldream/main/schemas/howl.exploration_result.v1.schema.json",
+  "$schema": "https://json-schema.org/draft/2020-12/schema",
+  "additionalProperties": false,
+  "description": "Complete machine-readable outcome returned by HowlDream: howl.exploration_result/v1.",
+  "properties": {
+    "authority": {
+      "$ref": "#/$defs/ExplorationAuthority"
+    },
+    "candidates": {
+      "items": {
+        "$ref": "#/$defs/CandidateHandoff"
+      },
+      "title": "Candidates",
+      "type": "array"
+    },
+    "claims": {
+      "items": {
+        "additionalProperties": true,
+        "type": "object"
+      },
+      "title": "Claims",
+      "type": "array"
+    },
+    "contradictions": {
+      "items": {
+        "type": "string"
+      },
+      "title": "Contradictions",
+      "type": "array"
+    },
+    "descent_dag": {
+      "$ref": "#/$defs/DescentDAG"
+    },
+    "evidence": {
+      "items": {
+        "additionalProperties": true,
+        "type": "object"
+      },
+      "title": "Evidence",
+      "type": "array"
+    },
+    "exploration_id": {
+      "maxLength": 100,
+      "minLength": 1,
+      "title": "Exploration Id",
+      "type": "string"
+    },
+    "objective": {
+      "maxLength": 10000,
+      "minLength": 1,
+      "title": "Objective",
+      "type": "string"
+    },
+    "originating_component": {
+      "maxLength": 100,
+      "minLength": 1,
+      "title": "Originating Component",
+      "type": "string"
+    },
+    "parent_request_id": {
+      "maxLength": 100,
+      "minLength": 1,
+      "title": "Parent Request Id",
+      "type": "string"
+    },
+    "provenance": {
+      "$ref": "#/$defs/Provenance"
+    },
+    "recommended_disposition": {
+      "default": "DEFER",
+      "enum": [
+        "INVESTIGATE",
+        "REJECT",
+        "DEFER",
+        "ACCEPT_FOR_DEVELOPMENT"
+      ],
+      "title": "Recommended Disposition",
+      "type": "string"
+    },
+    "schema_version": {
+      "const": "howl.exploration_result/v1",
+      "default": "howl.exploration_result/v1",
+      "title": "Schema Version",
+      "type": "string"
+    },
+    "scores": {
+      "items": {
+        "additionalProperties": true,
+        "type": "object"
+      },
+      "title": "Scores",
+      "type": "array"
+    },
+    "unresolved_assumptions": {
+      "items": {
+        "type": "string"
+      },
+      "title": "Unresolved Assumptions",
+      "type": "array"
+    },
+    "verification_status": {
+      "default": "UNVERIFIED",
+      "enum": [
+        "UNVERIFIED",
+        "REQUIRES_DOWNSTREAM_REVIEW",
+        "LOCALLY_VERIFIED"
+      ],
+      "title": "Verification Status",
+      "type": "string"
+    }
+  },
+  "required": [
+    "exploration_id",
+    "parent_request_id",
+    "objective",
+    "originating_component"
+  ],
+  "title": "HowlDream Exploration Result (howl.exploration_result/v1)",
+  "type": "object"
+}
diff --git a/contracts/howl/howl.go b/contracts/howl/howl.go
new file mode 100644
index 0000000..3ebb147
--- /dev/null
+++ b/contracts/howl/howl.go
@@ -0,0 +1,68 @@
+// Package howl loads the vendored howl.* ecosystem contract schemas and
+// compiles them for validation. The schema files in this directory are
+// vendored, generated copies from HowlDream — see SOURCE.md. This package
+// never imports or shells out to howldream; it only reads the local JSON
+// Schema files.
+package howl
+
+import (
+	"bytes"
+	"embed"
+	"encoding/json"
+	"fmt"
+
+	"github.com/santhosh-tekuri/jsonschema/v5"
+)
+
+//go:embed *.schema.json
+var schemaFS embed.FS
+
+// Names of the vendored schema files, keyed by their howl.* family slug.
+const (
+	Exploration       = "howl.exploration.v1.schema.json"
+	Candidate         = "howl.candidate.v1.schema.json"
+	Assessment        = "howl.assessment.v1.schema.json"
+	DevelopmentResult = "howl.development_result.v1.schema.json"
+	ExplorationResult = "howl.exploration_result.v1.schema.json"
+)
+
+// Compile loads and compiles the named vendored schema file (one of the
+// constants above). It registers the schema under its own declared $id so
+// internal $ref resolution works with no network access.
+func Compile(fileName string) (*jsonschema.Schema, error) {
+	raw, err := schemaFS.ReadFile(fileName)
+	if err != nil {
+		return nil, fmt.Errorf("read vendored schema %s: %w", fileName, err)
+	}
+
+	var doc struct {
+		ID string `json:"$id"`
+	}
+	if err := json.Unmarshal(raw, &doc); err != nil {
+		return nil, fmt.Errorf("parse $id from %s: %w", fileName, err)
+	}
+	if doc.ID == "" {
+		return nil, fmt.Errorf("schema %s has no $id", fileName)
+	}
+
+	compiler := jsonschema.NewCompiler()
+	if err := compiler.AddResource(doc.ID, bytes.NewReader(raw)); err != nil {
+		return nil, fmt.Errorf("register schema resource %s: %w", doc.ID, err)
+	}
+	schema, err := compiler.Compile(doc.ID)
+	if err != nil {
+		return nil, fmt.Errorf("compile schema %s: %w", doc.ID, err)
+	}
+	return schema, nil
+}
+
+// ValidateJSON decodes raw JSON and validates it against the compiled schema.
+func ValidateJSON(schema *jsonschema.Schema, raw []byte) error {
+	decoder := json.NewDecoder(bytes.NewReader(raw))
+	decoder.UseNumber()
+	var v interface{}
+	if err := decoder.Decode(&v); err != nil {
+		return fmt.Errorf("decode envelope JSON: %w", err)
+	}
+	return schema.Validate(v)
+}
diff --git a/go.mod b/go.mod
index 8cbbe6d..c5fbee4 100644
--- a/go.mod
+++ b/go.mod
@@ -1,3 +1,5 @@
 module github.com/howlcipher/howlframe
 
 go 1.21
+
+require github.com/santhosh-tekuri/jsonschema/v5 v5.3.1
diff --git a/go.sum b/go.sum
new file mode 100644
index 0000000..0daed30
--- /dev/null
+++ b/go.sum
@@ -0,0 +1,2 @@
+github.com/santhosh-tekuri/jsonschema/v5 v5.3.1 h1:lZUw3E0/J3roVtGQ+SCrUrg3ON6NgVqpn3+iol9aGu4=
+github.com/santhosh-tekuri/jsonschema/v5 v5.3.1/go.mod h1:uToXkOrWAZ6/Oc07xWQrPOhJotwFIyu2bBVN41fcDUY=