diff --git a/document-parser/domain/models.py b/document-parser/domain/models.py
index 66fc3fe..3faec9a 100644
--- a/document-parser/domain/models.py
+++ b/document-parser/domain/models.py
@@ -53,6 +53,7 @@ class AnalysisJob:
     document_filename: str | None = None
 
     def mark_running(self) -> None:
+        """Transition to RUNNING and record the start timestamp."""
         self.status = AnalysisStatus.RUNNING
         self.started_at = _utcnow()
 
@@ -64,6 +65,7 @@ class AnalysisJob:
         document_json: str | None = None,
         chunks_json: str | None = None,
     ) -> None:
+        """Transition to COMPLETED with conversion results."""
         self.status = AnalysisStatus.COMPLETED
         self.content_markdown = markdown
         self.content_html = html
@@ -73,6 +75,7 @@ class AnalysisJob:
         self.completed_at = _utcnow()
 
     def mark_failed(self, error: str) -> None:
+        """Transition to FAILED with an error message."""
         self.status = AnalysisStatus.FAILED
         self.error_message = error
         self.completed_at = _utcnow()
diff --git a/document-parser/domain/value_objects.py b/document-parser/domain/value_objects.py
index 26e19fc..7c91845 100644
--- a/document-parser/domain/value_objects.py
+++ b/document-parser/domain/value_objects.py
@@ -39,6 +39,7 @@ class ConversionOptions:
     images_scale: float = 1.0
 
     def is_default(self) -> bool:
+        """Return True if all options match their defaults."""
         return self == ConversionOptions()
 
 
@@ -60,6 +61,7 @@ class ChunkingOptions:
     repeat_table_header: bool = True
 
     def is_default(self) -> bool:
+        """Return True if all options match their defaults."""
         return self == ChunkingOptions()
 
 
diff --git a/document-parser/persistence/analysis_repo.py b/document-parser/persistence/analysis_repo.py
index 9d6a7a7..deb08b6 100644
--- a/document-parser/persistence/analysis_repo.py
+++ b/document-parser/persistence/analysis_repo.py
@@ -42,6 +42,7 @@ _SELECT_WITH_DOC = """
 
 
 async def insert(job: AnalysisJob) -> None:
+    """Persist a new analysis job record."""
     async with get_connection() as db:
         await db.execute(
             """INSERT INTO analysis_jobs (id, document_id, status, created_at)
@@ -52,6 +53,7 @@ async def insert(job: AnalysisJob) -> None:
 
 
 async def find_all(*, limit: int = 200, offset: int = 0) -> list[AnalysisJob]:
+    """Return analysis jobs with document info, newest first."""
     async with get_connection() as db:
         cursor = await db.execute(
             f"{_SELECT_WITH_DOC} ORDER BY aj.created_at DESC LIMIT ? OFFSET ?",
@@ -62,6 +64,7 @@ async def find_all(*, limit: int = 200, offset: int = 0) -> list[AnalysisJob]:
 
 
 async def find_by_id(job_id: str) -> AnalysisJob | None:
+    """Find an analysis job by ID (with document filename), or return None."""
     async with get_connection() as db:
         cursor = await db.execute(f"{_SELECT_WITH_DOC} WHERE aj.id = ?", (job_id,))
         row = await cursor.fetchone()
@@ -69,6 +72,7 @@ async def find_by_id(job_id: str) -> AnalysisJob | None:
 
 
 async def update_status(job: AnalysisJob) -> None:
+    """Persist all mutable fields of an analysis job (status, results, timestamps)."""
     async with get_connection() as db:
         await db.execute(
             """UPDATE analysis_jobs
@@ -104,6 +108,7 @@ async def update_chunks(job_id: str, chunks_json: str) -> bool:
 
 
 async def delete(job_id: str) -> bool:
+    """Delete an analysis job by ID. Returns True if a row was removed."""
     async with get_connection() as db:
         cursor = await db.execute("DELETE FROM analysis_jobs WHERE id = ?", (job_id,))
         await db.commit()
diff --git a/document-parser/persistence/document_repo.py b/document-parser/persistence/document_repo.py
index 04ac473..3c946de 100644
--- a/document-parser/persistence/document_repo.py
+++ b/document-parser/persistence/document_repo.py
@@ -26,6 +26,7 @@ def _row_to_document(row) -> Document:
 
 
 async def insert(doc: Document) -> None:
+    """Persist a new document record."""
     async with get_connection() as db:
         await db.execute(
             """INSERT INTO documents (id, filename, content_type, file_size, page_count, storage_path, created_at)
@@ -44,6 +45,7 @@ async def insert(doc: Document) -> None:
 
 
 async def find_all(*, limit: int = 200, offset: int = 0) -> list[Document]:
+    """Return documents ordered by creation date (newest first)."""
     async with get_connection() as db:
         cursor = await db.execute(
             "SELECT * FROM documents ORDER BY created_at DESC LIMIT ? OFFSET ?",
@@ -54,6 +56,7 @@ async def find_all(*, limit: int = 200, offset: int = 0) -> list[Document]:
 
 
 async def find_by_id(doc_id: str) -> Document | None:
+    """Find a document by its ID, or return None."""
     async with get_connection() as db:
         cursor = await db.execute("SELECT * FROM documents WHERE id = ?", (doc_id,))
         row = await cursor.fetchone()
@@ -61,6 +64,7 @@ async def find_by_id(doc_id: str) -> Document | None:
 
 
 async def update_page_count(doc_id: str, page_count: int) -> None:
+    """Update the page count after conversion has determined it."""
     async with get_connection() as db:
         await db.execute(
             "UPDATE documents SET page_count = ? WHERE id = ?",
@@ -70,6 +74,7 @@ async def update_page_count(doc_id: str, page_count: int) -> None:
 
 
 async def delete(doc_id: str) -> bool:
+    """Delete a document by ID. Returns True if a row was removed."""
     async with get_connection() as db:
         cursor = await db.execute("DELETE FROM documents WHERE id = ?", (doc_id,))
         await db.commit()
diff --git a/document-parser/services/analysis_service.py b/document-parser/services/analysis_service.py
index 74b8b28..93c556f 100644
--- a/document-parser/services/analysis_service.py
+++ b/document-parser/services/analysis_service.py
@@ -83,12 +83,15 @@ class AnalysisService:
         return job
 
     async def find_all(self) -> list[AnalysisJob]:
+        """Return all analysis jobs, newest first."""
         return await analysis_repo.find_all()
 
     async def find_by_id(self, job_id: str) -> AnalysisJob | None:
+        """Find an analysis job by ID, or return None."""
         return await analysis_repo.find_by_id(job_id)
 
     async def delete(self, job_id: str) -> bool:
+        """Delete an analysis job. Returns True if it existed."""
         return await analysis_repo.delete(job_id)
 
     async def rechunk(self, job_id: str, chunking_options: dict) -> list[ChunkResult]:
diff --git a/document-parser/services/document_service.py b/document-parser/services/document_service.py
index 3b564a8..d54ebfb 100644
--- a/document-parser/services/document_service.py
+++ b/document-parser/services/document_service.py
@@ -63,10 +63,12 @@ async def upload(filename: str, content_type: str, file_content: bytes) -> Docum
 
 
 async def find_all() -> list[Document]:
+    """Return all documents, newest first."""
     return await document_repo.find_all()
 
 
 async def find_by_id(doc_id: str) -> Document | None:
+    """Find a document by its ID, or return None."""
     return await document_repo.find_by_id(doc_id)