diff --git a/.opencode/agents/ca-implementer-codex.md b/.opencode/agents/ca-implementer-codex.md
index b877d93c8..73074af80 100644
--- a/.opencode/agents/ca-implementer-codex.md
+++ b/.opencode/agents/ca-implementer-codex.md
@@ -64,12 +64,25 @@ Follow these rules strictly:
 1. Read and understand the subtask requirements.
 2. Read any existing code in the relevant modules to understand the current
    state.
-3. Implement the required changes:
+3. **Verify domain model fields exist (CRITICAL).** Before writing code that
+   references any field, method, or attribute on a domain model class, you
+   MUST verify it exists by reading the actual class definition. **Never
+   assume a field exists based solely on the issue description.** Issue
+   descriptions often describe *desired* behavior — the field may not yet
+   exist in the codebase. Specifically:
+   - Before accessing `model.some_field`, read the model class to confirm
+     `some_field` is defined.
+   - Before calling `service.some_method()`, read the service class to
+     confirm `some_method` exists with the expected signature.
+   - If a required field or method does not exist, you must CREATE it as
+     part of your implementation (including database schema changes if
+     needed), not just reference it and hope it exists.
+4. Implement the required changes:
    - Write clean, well-typed Python code.
    - Follow the architectural patterns from the specification.
    - Add appropriate docstrings and inline comments for complex logic.
-4. Do NOT write tests (separate agents handle testing).
-5. Do NOT run nox or quality checks (separate agents handle this).
+5. Do NOT write tests (separate agents handle testing).
+6. Do NOT run nox or quality checks (separate agents handle this).
 
 ## Escalation Context
 
diff --git a/.opencode/agents/ca-implementer-opus.md b/.opencode/agents/ca-implementer-opus.md
index 597e71b36..02b516031 100644
--- a/.opencode/agents/ca-implementer-opus.md
+++ b/.opencode/agents/ca-implementer-opus.md
@@ -65,12 +65,25 @@ Follow these rules strictly:
 1. Read and understand the subtask requirements.
 2. Read any existing code in the relevant modules to understand the current
    state.
-3. Implement the required changes:
+3. **Verify domain model fields exist (CRITICAL).** Before writing code that
+   references any field, method, or attribute on a domain model class, you
+   MUST verify it exists by reading the actual class definition. **Never
+   assume a field exists based solely on the issue description.** Issue
+   descriptions often describe *desired* behavior — the field may not yet
+   exist in the codebase. Specifically:
+   - Before accessing `model.some_field`, read the model class to confirm
+     `some_field` is defined.
+   - Before calling `service.some_method()`, read the service class to
+     confirm `some_method` exists with the expected signature.
+   - If a required field or method does not exist, you must CREATE it as
+     part of your implementation (including database schema changes if
+     needed), not just reference it and hope it exists.
+4. Implement the required changes:
    - Write clean, well-typed Python code.
    - Follow the architectural patterns from the specification.
    - Add appropriate docstrings and inline comments for complex logic.
-4. Do NOT write tests (separate agents handle testing).
-5. Do NOT run nox or quality checks (separate agents handle this).
+5. Do NOT write tests (separate agents handle testing).
+6. Do NOT run nox or quality checks (separate agents handle this).
 
 ## Escalation Context
 
diff --git a/.opencode/agents/ca-implementer-sonnet.md b/.opencode/agents/ca-implementer-sonnet.md
index 9a7139d1a..055d6b19f 100644
--- a/.opencode/agents/ca-implementer-sonnet.md
+++ b/.opencode/agents/ca-implementer-sonnet.md
@@ -64,12 +64,25 @@ Follow these rules strictly:
 1. Read and understand the subtask requirements.
 2. Read any existing code in the relevant modules to understand the current
    state.
-3. Implement the required changes:
+3. **Verify domain model fields exist (CRITICAL).** Before writing code that
+   references any field, method, or attribute on a domain model class, you
+   MUST verify it exists by reading the actual class definition. **Never
+   assume a field exists based solely on the issue description.** Issue
+   descriptions often describe *desired* behavior — the field may not yet
+   exist in the codebase. Specifically:
+   - Before accessing `model.some_field`, read the model class to confirm
+     `some_field` is defined.
+   - Before calling `service.some_method()`, read the service class to
+     confirm `some_method` exists with the expected signature.
+   - If a required field or method does not exist, you must CREATE it as
+     part of your implementation (including database schema changes if
+     needed), not just reference it and hope it exists.
+4. Implement the required changes:
    - Write clean, well-typed Python code.
    - Follow the architectural patterns from the specification.
    - Add appropriate docstrings and inline comments for complex logic.
-4. Do NOT write tests (separate agents handle testing).
-5. Do NOT run nox or quality checks (separate agents handle this).
+5. Do NOT write tests (separate agents handle testing).
+6. Do NOT run nox or quality checks (separate agents handle this).
 
 ## Escalation Context